Astrophysics
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New submissions for Tue, 21 Apr 20
- [1] arXiv:2004.08392 [pdf, other]
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Title: Origin of Spin-Orbit Misalignments: The Microblazar V4641 SgrComments: Accepted to MNRAS; 36 pages, 18 figuresSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
Of the known microquasars, V4641 Sgr boasts the most severe lower limit (> 52{\deg}) on the misalignment angle between the relativistic jet axis and the binary orbital angular momentum. Assuming the jet and black hole spin axes coincide, we attempt to explain the origin of this extreme spin-orbit misalignment with a natal kick model, whereby an aligned binary system becomes misaligned by a supernova kick imparted to the newborn black hole. The model inputs are the kick velocity distribution, which we measure customized to V4641 Sgr, and the immediate pre/post-supernova binary system parameters. Using a grid of binary stellar evolution models, we determine post-supernova configurations that evolve to become consistent with V4641 Sgr today and obtain the corresponding pre-supernova configurations by using standard prescriptions for common envelope evolution. Using each of these potential progenitor system parameter sets as inputs, we find that a natal kick struggles to explain the origin of the V4641 Sgr spin-orbit misalignment. Consequently, we conclude that evolutionary pathways involving a standard common envelope phase followed by a supernova kick are highly unlikely for V4641 Sgr. An alternative interpretation is that the jet axis does not reliably trace the black hole spin axis. Our results raise concerns about compact object merger statistics gleaned from binary population synthesis models, which rely on unverified prescriptions for common envelope evolution and natal kicks. We also challenge the spin-orbit alignment assumption routinely invoked to measure black hole spin magnitudes.
- [2] arXiv:2004.08393 [pdf, other]
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Title: Cosmology-insensitive estimate of IGM baryon mass fraction from five localized fast radio burstsComments: 6 pages, 3 figures, accepted for publication in MNRAS LettersSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc)
Five fast radio bursts (FRBs), including three apparently non-repeating ones FRB 180924, FRB 181112, and FRB 190523, and two repeaters, FRB 121102 and FRB 180916.J0158+65, have already been localized so far. We apply a method developed recently by us (Li et al. 2019) to these five localized FRBs to give a cosmology-insensitive estimate of the fraction of baryon mass in the IGM, $f_{\rm IGM}$. Using the measured dispersion measure (DM) and luminosity distance $d_{\rm L}$ data (inferred from the FRB redshifts and $d_{\rm L}$ of type Ia supernovae at the same redshifts) of the five FRBs, we constrain the local $f_{\rm IGM} = 0.84^{+0.16}_{-0.22}$ with no evidence of redshift dependence. This cosmology-insensitive estimate of $f_{\rm IGM}$ from FRB observations is in excellent agreement with previous constraints using other probes. Moreover, using the three apparently non-repeating FRBs only we get a little looser but consistent result $f_{\rm IGM} = 0.74^{+0.24}_{-0.18}$. In these two cases, reasonable estimations for the host galaxy DM contribution (${\rm DM_{host}}$) can be achieved by modelling it as a function of star formation rate. The constraints on both $f_{\rm IGM}$ and ${\rm DM_{host}}$ are expected to be significantly improved with the rapid progress in localizing FRBs.
- [3] arXiv:2004.08395 [pdf, other]
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Title: The Dekel+ profile: a mass-dependent dark-matter density profile with flexible inner slope and analytic potential, velocity dispersion, and lensing propertiesAuthors: Jonathan Freundlich, Fangzhou Jiang, Avishai Dekel, Nicolas Cornuault, Omry Ginzburg, Rémy Koskas, Sharon Lapiner, Aaron A. Dutton, Andrea V. MacciòComments: Submitted to MNRAS, 20 pages (main) + 18 pages (appendices)Subjects: Astrophysics of Galaxies (astro-ph.GA)
Using the NIHAO suite of cosmological zoom-in simulations, we explore a parametric function for the dark-matter halo density profile subject to baryonic effects. This profile has variable inner slope and concentration parameter, and it allows analytic expressions for the gravitational potential, velocity dispersion, and lensing properties. We show that this profile provides better fits to simulated profiles than the Einasto profile and the generalized NFW profile with variable inner slope, in particular towards the halo centers, and that its parameters are correlated with the stellar-to-halo mass ratio $M_{\rm star}/M_{\rm vir}$. This defines a mass-dependent density profile describing the dark matter profiles in all galaxies, which can be directly applied to observed rotation curves of galaxies, gravitational lenses, and semi-analytic models of galaxy formation and satellite-galaxy evolution. The effect of baryons manifests itself in the profile parameters by a sharp drop of the inner density slope and a 20% decrease of the concentration parameter for $\log(M_{\rm star}/M_{\rm vir})$ between -3.5 and -2, which corresponds to $M_{\rm star}$ between $10^7$ and $10^{10}~\rm M_\odot$. The accuracy by which this profile fits simulated galaxies is similar to certain multi-parameter, mass-dependent profiles, but its fewer parameters and analytic nature make it most desirable for many purposes.
- [4] arXiv:2004.08397 [pdf, other]
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Title: The Origin and Evolution of Lyman-alpha Blobs in Cosmological Galaxy Formation SimulationsAuthors: Benjamin Kimock, Desika Narayanan, Aaron Smith, Xiangcheng Ma, Robert Feldmann, Daniel Anglés-Alcázar, Romeel Dave, James E. Geach, Philip Hopkins, Dušan KerešComments: Submitted to ApJ; comments welcome. 23 pages, 21 figuresSubjects: Astrophysics of Galaxies (astro-ph.GA)
High-redshift Lyman-alpha blobs (LABs) are an enigmatic class of objects that have been the subject of numerous observational and theoretical investigations. It is of particular interest to determine the dominant power sources for the copious luminosity, as direct emission from HII regions, cooling gas, and fluorescence due to the presence of active galactic nuclei (AGN) can all contribute significantly. In this paper, we present the first theoretical model to consider all of these physical processes in an attempt to develop an evolutionary model for the origin of high-z LABs. This is achieved by combining a series of high-resolution cosmological zoom-in simulations with ionization and Lyman-alpha (Lya) radiative transfer models. We find that massive galaxies display a range of Lya luminosities and spatial extents (which strongly depend on the limiting surface brightness used) over the course of their lives, though regularly exhibit luminosities and sizes consistent with observed LABs. The model LABs are typically powered from a combination of recombination in star-forming galaxies, as well as cooling emission from gas associated with accretion. When AGN are included in the model, the fluorescence caused by AGN-driven ionization can be a significant contributor to the total Lya luminosity as well. We propose that the presence of an AGN may be predicted from the Gini coefficient of the blob's surface brightness. Within our modeled mass range, there are no obvious threshold physical properties that predict appearance of LABs, and only weak correlations of the luminosity with the physical properties of the host galaxy. This is because the emergent Lya luminosity from a system is a complex function of the gas temperature, ionization state, and Lya escape fraction.
- [5] arXiv:2004.08400 [pdf, other]
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Title: A transient optical laser at cosmological distance probes the circum-stellar material 2.8 Gyr after the Big BangAuthors: E. Vanzella, M. Meneghetti, A. Pastorello, F. Calura, E. Sani, G. Cupani, G.B. Caminha, M. Castellano, P. Rosati, V. D'Odorico, S. Cristiani, C. Grillo, A. Mercurio, M. Nonino, G.B. BrammerComments: 5 pages, 4 figures. Submitted to MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA)
We discovered Bowen emission arising from a strongly lensed ($\mu>20$) transient stellar object hosted in the Sunburst arc at z=2.37. Unique ultraviolet lines emerge at the location of the transient. In particular, narrow ($\sigma_v$ ~ 40 km/s) ionisation lines of several chemical species (Fe, C, Si) fluoresce after being exposed to Lyman series (e.g., Ly$\alpha$, Ly$\beta$) of H, HeI and HeII that pump selectively their atomic levels. Similarities with the Resonance-Enhanced Two Photon-Ionisation (RETPI) spectral features observed in the circum-stellar Weigelt blobs of Eta~Carinae are observed. Data from VLT/MUSE, X-Shooter and ESPRESSO observations (the latter placed at the focus of the four UTs) at increasing spectral resolution of R=2500, 11400 and R=70000, respectively, confirm the lasing action since at least 3.3 years (~ 1 year rest-frame), and probe the circum-stellar dense gas condensations in radiation-rich conditions. We discuss the physical origin of the transient event, which remains unclear. We expect such transient events (including also supernova or impostors) will be easily recognised with ELTs thanks to high angular resolution provided by adaptive optics and large collecting area, especially in modest ($\mu < 3$) magnification regime.
- [6] arXiv:2004.08401 [pdf, other]
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Title: Astraeus I: The interplay between galaxy formation and reionizationAuthors: Anne Hutter, Pratika Dayal, Gustavo Yepes, Stefan Gottlöber, Laurent Legrand, Graziano UcciComments: 26 pages, 13 figures, submitted to MNRAS, comments welcomeSubjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
We introduce a new self-consistent model of galaxy evolution and reionization, ASTRAEUS (semi-numerical rAdiative tranSfer coupling of galaxy formaTion and Reionization in N-body dArk mattEr simUlationS), which couples a state-of-the-art N-body simulation with the semi-analytical galaxy evolution DELPHI and the semi-numerical reionization scheme CIFOG. ASTRAEUS includes all the key processes of galaxy formation and evolution (including accretion, mergers, supernova and radiative feedback) and follows the time and spatial evolution of the ionized regions in the intergalactic medium (IGM). Importantly, it explores different radiative feedback models that cover the physically plausible parameter space, ranging from a weak and delayed to a strong and immediate reduction of gas mass available for star formation. From our simulation suite that covers the different radiative feedback prescriptions and ionization topologies, we find that radiative feedback continuously reduces star formation in galaxies with $M_h<10^{9.5}M_{\odot}$ upon local reionization; larger mass halos are unaffected even for the strongest and immediate radiative feedback cases during reionization. For this reason, the ionization topologies of different radiative feedback scenarios differ only on scales smaller than $1-2$Mpc, and significant deviations are only found when physical parameters (e.g. the escape fraction of ionizing photons) are altered based on galactic properties. Finally, we find observables (the ultra-violet luminosity function, stellar mass function, reionization histories and ionization topologies) are hardly affected by the choice of the used stellar population synthesis models that either model single stars or binaries.
- [7] arXiv:2004.08405 [pdf, other]
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Title: A new tool to derive chemical abundances in Type-2 Active Galactic NucleiComments: Proceedings paper of the IAU symposium "Nuclear Activity in Galaxies Across Cosmic Time" (Ethiopia) accepted to be published under the Cambridge University Press, eds. M. Povi\'c, P. Marziani, J. Masegosa, H. Netzer, S. H. Negu, and S. B. TessemaSubjects: Astrophysics of Galaxies (astro-ph.GA)
We present a new tool for the analysis of the optical emission lines of the gas in the Narrow Line Region (NLR) around Active Galactic Nuclei (AGNs). This new tool can be used in large samples of objects in a consistent way using different sets of optical emission-lines taking into the account possible variations from the O/H - N/O relation. The code compares certain observed emission-line ratios with the predictions from a large grid of photoionization models calculated under the most usual conditions in the NLR of AGNs to calculate the total oxygen abundance, nitrogen-to-oxygen ratio and ionization parameter. We applied our method to a sample of Seyfert 2 galaxies with optical emission-line fluxes from the literature. Our results confirm the high metallicity of the objects of the sample and provide consistent values with the direct method. The usage of models to calculate precise ICFs is mandatory when only optical emission lines are available to derive chemical abundances using the direct method in NLRs of AGN.
- [8] arXiv:2004.08406 [pdf, other]
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Title: Testing dark matter halo properties using self-similarityComments: 8 pages, 8 figures, submitted, comments welcomeSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA)
We use self-similarity in N-body simulations of scale-free models to test for resolution dependence in the mass function and two-point correlation functions of dark matter halos. We use 1024$^3$ particle simulations performed with the ABACUS N-body code and define halos with two different algorithms, "friends of friends" (FOF) and ROCKSTAR. The FOF mass functions show a systematic deviation from self-similarity which is explained by a resolution dependence of the FOF mass assignment previously reported in the literature. Evidence for convergence is observed only starting from halos of several thousand particles, and mass functions are overestimated by as much as 20-25 percent for halos of 50 particles. The mass function of ROCKSTAR halos, on the other hand, shows good convergence from of order 50 to 100 particles per halo, with no detectable evidence at the one percent level of any systematic dependence for larger particle number. Tests show that the mass unbinding procedure in ROCKSTAR is the key factor in obtaining this much improved resolution. Applying the same analysis to the halo-halo two point correlation function, we find again strong evidence for convergence only for ROCKSTAR halos, at separations sufficiently large so that halos do not overlap. At these separations we can exclude dependence on resolution at the few percent level once halos have of order 50 to 100 particles. At smaller separations results are not converged even at significantly larger particle number, and bigger simulations would be required to establish the resolution required for convergence.
- [9] arXiv:2004.08408 [pdf, other]
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Title: Mapping and characterisation of cosmic filaments in galaxy cluster outskirts: strategies and forecasts for observations from simulationsAuthors: Ulrike Kuchner, Alfonso Aragón-Salamanca, Frazer R. Pearce, Meghan E. Gray, Agustín Rost, Chunliang Mu, Charlotte Welker, Weiguang Cui, Roan Haggar, Clotilde Laigle, Alexander Knebe, Katarina Kraljic, Florian Sarron, Gustavo YepesComments: 22 pages, 17 figures, accepted for publication in MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA)
Upcoming wide-field surveys are well-suited to studying the growth of galaxy clusters by tracing galaxy and gas accretion along cosmic filaments. We use hydrodynamic simulations of volumes surrounding 324 clusters from \textsc{The ThreeHundred} project to develop a framework for identifying and characterising these filamentary structures, and associating galaxies with them. We define 3-dimensional reference filament networks reaching $5R_{200}$ based on the underlying gas distribution and quantify their recovery using mock galaxy samples mimicking observations such as those of the WEAVE Wide-Field Cluster Survey. Since massive galaxies trace filaments, they are best recovered by mass-weighting galaxies or imposing a bright limit (e.g. $>L^*$) on their selection. We measure the transverse gas density profile of filaments, derive a characteristic filament radius of $\simeq0.7$--$1~h^{-1}\rm{Mpc}$, and use this to assign galaxies to filaments. For different filament extraction methods we find that at $R>R_{200}$, $\sim15$--$20%$ of galaxies with $M_*>3 \times 10^9 M_{\odot}$ are in filaments, increasing to $\sim60%$ for galaxies more massive than the Milky-Way. The fraction of galaxies in filaments is independent of cluster mass and dynamical state, and is a function of cluster-centric distance, increasing from $\sim13$% at $5R_{200}$ to $\sim21$% at $1.5R_{200}$. As a bridge to the design of observational studies, we measure the purity and completeness of different filament galaxy selection strategies. Encouragingly, the overall 3-dimensional filament networks and $\sim67$% of the galaxies associated with them are recovered from 2-dimensional galaxy positions.
- [10] arXiv:2004.08414 [pdf, other]
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Title: The dependence of global super-rotation on planetary rotation rateComments: Submitted to Journal of the Atmospheric Sciences. Comments welcome. This manuscript has not yet been peer reviewedSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Atmospheric and Oceanic Physics (physics.ao-ph)
An atmosphere may be described as globally super-rotating if its total zonal angular momentum exceeds that associated with solid-body co-rotation with the underlying planet. In this paper, we discuss the dependence of global super-rotation in terrestrial atmospheres on planetary rotation rate. This dependence is revealed through analysis of global super-rotation in idealised General Circulation Model experiments with time-independent axisymmetric forcing, compared with estimates for global super-rotation in Solar System atmospheres. Axisymmetric and three-dimensional experiments are conducted. We find that the degree of global super-rotation in the three-dimensional experiments is closely related to that of the axisymmetric experiments, with some differences in detail. A scaling theory for global super-rotation in an axisymmetric atmosphere is derived from the Held-Hou model. At high rotation rate, our numerical experiments inhabit a regime where global super-rotation scales geostrophically, and we suggest that the Earth and Mars occupy this regime. At low rotation rate, our experiments occupy a regime determined by angular momentum conservation, where global super-rotation is independent of rotation rate. Global super-rotation in our experiments saturates at a value significantly lower than that achieved in the atmospheres of Venus and Titan, which instead occupy a regime where global super-rotation scales cyclostrophically. This regime can only be accessed when eddy induced up-gradient angular momentum transport is sufficiently large, which is not the case in our idealised numerical experiments. We suggest that the 'default' regime for a slowly rotating planet is the angular momentum conserving regime, characterised by mild global (and local) superrotation.
- [11] arXiv:2004.08415 [pdf, other]
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Title: High-resolution Transmission Spectroscopy of MASCARA-2 b with EXPRESAuthors: H. Jens Hoeijmakers, Samuel H. C. Cabot, Lily Zhao, Lars A. Buchhave, René Tronsgaard, Daniel Kitzmann, Simon L. Grimm, Heather M. Cegla, Vincent Bourrier, David Ehrenreich, Kevin Heng, Christophe Lovis, Debra A. FischerComments: Accepted for publication in A&A, 20 pages, 22 figuresSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM)
We report detections of atomic species in the atmosphere of MASCARA-2 b, using the first transit observations obtained with the newly commissioned EXPRES spectrograph. EXPRES is a highly stabilised optical echelle spectrograph, designed to detect stellar reflex motions with amplitudes down to 30 cm/s, and was recently deployed at the Lowell Discovery Telescope. By analysing the transmission spectrum of the ultra-hot Jupiter MASCARA-2 b using the cross-correlation method, we confirm previous detections of Fe I, Fe II and Na I, which likely originate in the upper regions of the inflated atmosphere. In addition, we report significant detections of Mg I and Cr II. The absorption strengths change slightly with time, possibly indicating different temperatures and chemistry in the day-side and night-side terminators. Using the effective stellar line-shape variation induced by the transiting planet, we constrain the projected spin-orbit misalignment of the system to $1.6\pm3.1$ degrees, consistent with an aligned orbit. We demonstrate that EXPRES joins a suite of instruments capable of phase-resolved spectroscopy of exoplanet atmospheres.
- [12] arXiv:2004.08455 [pdf, other]
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Title: Multi wavelength cross-correlation analysis of the simulated cosmic webComments: 16 pages, 15 figures, accepted for publication by MNRASSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
We used magneto-hydrodynamical cosmological simulations to investigate the cross-correlation between different observables (i.e. X-ray emission, Sunyaev-Zeldovich signal at 21 cm, HI temperature decrement, diffuse synchrotron emission and Faraday Rotation) as a probe of the diffuse matter distribution in the cosmic web. We adopt an uniform and simplistic approach to produce synthetic observations at various wavelengths, and we compare the detection chances of different combinations of observables correlated with each other and with the underlying galaxy distribution in the volume. With presently available surveys of galaxies and existing instruments, the best chances to detect the diffuse gas in the cosmic web outside of halos is by cross-correlating the distribution of galaxies with Sunyaev-Zeldovich observations. We also find that the cross-correlation between the galaxy network and the radio emission or the Faraday Rotation can already be used to limit the amplitude of extragalactic magnetic fields, well outside of the cluster volume usually explored by existing radio observations, and to probe the origin of cosmic magnetism with the future generation of radio surveys.
- [13] arXiv:2004.08463 [pdf, other]
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Title: A Unified Calibration Framework for 21 cm CosmologySubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)
Calibration precision is currently a limiting systematic in 21 cm cosmology experiments. While there are innumerable calibration approaches, most can be categorized as either `sky-based,' relying on an extremely accurate model of astronomical foreground emission, or `redundant,' requiring a precisely regular array with near-identical antenna response patterns. Both of these classes of calibration are inflexible to the realities of interferometric measurement. In practice, errors in the foreground model, antenna position offsets, and beam response inhomogeneities degrade calibration performance and contaminate the cosmological signal. Here we show that sky-based and redundant calibration can be unified into a highly general and physically motivated calibration framework based on a Bayesian statistical formalism. Our new framework includes sky and redundant calibration as special cases but can additionally support relaxing the rigid assumptions implicit in those approaches. Furthermore, we present novel calibration techniques such as redundant calibration for arrays with no redundant baselines, representing an alternative calibration method for imaging arrays such as the MWA Phase I. These new calibration approaches could mitigate systematics and reduce calibration error, thereby improving the precision of cosmological measurements.
- [14] arXiv:2004.08477 [pdf, other]
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Title: Self-Interacting Dark Matter and the Delay of Super-Massive Black Hole GrowthAuthors: Akaxia Cruz, Andrew Pontzen, Marta Volonteri, Thomas R. Quinn, Michael Tremmel, Alyson M. Brooks, Nicole N. Sanchez, Ferah Munshi, Arianna Di CintioSubjects: Astrophysics of Galaxies (astro-ph.GA)
Using cosmological hydrodynamic simulations with physically motivated models of super-massive black hole (SMBH) formation and growth, we compare the assembly of Milky Way-mass ( $M_{\mathrm{vir}} \approx 7 \times 10^{11}$ $M_{\odot}$ at $z = 0$) galaxies in cold dark matter (CDM) and self-interacting dark matter (SIDM) models. Our SIDM model adopts a constant cross-section of 1 cm$^2$/g. We find that SMBH formation is suppressed in the early universe due to SIDM coring. SMBH-SMBH mergers are also suppressed in SIDM as a consequence of the lower number of SMBHs formed. Lack of initial merger-driven SMBH growth in turn delays SMBH growth by billions of years in SIDM compared to CDM. Further, we find that this delayed growth suppresses SMBH accretion in the largest progenitors of the main SIDM galaxies during the first 5 Gyrs of their evolution. Nonetheless, by $z = 0.8$ the CDM and SIDM SMBH masses differ only by around 0.2 dex, so that both remain compatible with the $M_{BH}-M_{*}$ relation. We show that the reduced accretion causes the SIDM SMBHs to less aggressively regulate star formation in their host galaxies than their CDM counterparts, resulting in a factor of 3 or more stars being produced over the lifetime of the SIDM galaxies compared to the CDM galaxies. Our results highlight a new way in which SIDM can affect the growth and merger history of SMBHs and ultimately give rise to very different galaxy evolution compared to the classic CDM model.
- [15] arXiv:2004.08479 [pdf, other]
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Title: Lessons on early structure formation from a mature galaxy cluster observed at cosmic noonComments: 7 pages, 5 figures, submitted to MNRASSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA)
We demonstrate a new approach of indirectly constraining both early star and structure formation via mature galaxy clusters at cosmic noon (z~2), using the cluster XLSSC 122 as an example. With the standard Press Schechter formalism, we infer a rapid evolution of the star formation efficiency (the ratio of stellar to halo mass) from 10^-4 to 0.01 during z~20-13, based on the age distribution of stars in post-starburst galaxies of XLSSC 122, measured by HST photometry assuming no dust extinction. Here, we consider all low-mass haloes, including minihaloes, that host the first stars and galaxies (5*10^5 Msun < M_halo < 10^10 Msun). We also place new constraints on fuzzy dark matter models of m_a < 5*10^-21 eV/c^2 for the ultra-light boson mass, from the abundance of galaxies with star formation at z > 13 in XLSSC 122. Our exploratory results are consistent with existing constraints. More comprehensive results will be obtained if our approach is extended to a large sample of clusters or field post-starburst galaxies at cosmic noon, with improved modelling of halo and stellar populations.
- [16] arXiv:2004.08482 [pdf, other]
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Title: Evolving Ultralight Scalars into Non-Linearity with Lagrangian Perturbation TheoryComments: Submitted to MNRAS, comments welcomeSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
Many models of high energy physics suggest that the cosmological dark sector consists of not just one, but a spectrum of ultralight scalar particles with logarithmically distributed masses. To study the potential signatures of low concentrations of ultralight axion (also known as fuzzy) dark matter, we modify Lagrangian perturbation theory (LPT) by distinguishing between trajectories of different dark matter species. We further adapt LPT to include the effects of a quantum pressure, which is necessary to generate correct initial conditions for ultralight axion simulations. Based on LPT, our modified scheme is extremely efficient on large scales and it can be extended to an arbitrary number of particle species at very little computational cost. This allows for computation of self-consistent initial conditions in mixed dark matter models. Additionally, we find that shell-crossing is delayed for ultralight particles and that the deformation tensor extracted from LPT can be used to identify the range of redshifts and scales for which the Madelung formalism of fuzzy dark matter is a reliable approximation.
- [17] arXiv:2004.08484 [pdf, other]
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Title: Probing variation of the fine-structure constant using the strong gravitational lensingComments: 8 pages, 3 figures, 1 tableSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA)
In order to probe a possible time variation of the fine-structure constant ($\alpha$), we propose a new method based on Strong Gravitational Lensing and Type Ia Supernovae observations. By considering a class of dilaton runaway models, where $\frac{\Delta \alpha}{\alpha}= - g \ln{(1+z)}$ ($g$ captures the physical properties of the model), we obtain constraints on $\frac{\Delta \alpha}{\alpha}$ at the level of $g \approx 10^{-2}$. Since the data set covers the redshift range $0.075 \leq z \leq 2.2649$, the constraints derived here provide independent bounds on a possible time variation of $\alpha$ at low, intermediate and high redshifts.
- [18] arXiv:2004.08502 [pdf, ps, other]
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Title: On aging star clusters using red supergiants independent of the fraction of interacting binary starsComments: Accepted for publication in MNRAS, 7 pages, 3 pages, 2 tablesSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)
We use the Binary Population and Spectral Synthesis (BPASS) models to test the recent suggestion that red supergiants can provide an accurate age estimate of a co-eval stellar population that is unaffected by interacting binary stars. Ages are estimated by using both the minimum luminosity red supergiant and the mean luminosity of red supergiants in a cluster. We test these methods on a number of observed star clusters and find our results in agreement with previous estimates. Importantly we find the difference between the ages derived from stellar population models with and without a realistic population of interacting binary stars is only a few 100,000 years at most. We find that the mean luminosity of red supergiants in a cluster is the best method to determine the age of a cluster because it is based o the entire red supergiant population rather than using only the least luminous red supergiant.
- [19] arXiv:2004.08521 [pdf, other]
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Title: A Foreground Model Independent Estimation of Joint Posterior of CMB E mode Polarization over Large Angular ScalesComments: 11 figures and 14 pagesSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Theory (hep-th)
Ever since Cosmic Microwave Background (CMB) signal is being measured by various satellites based observations with increasing experimental accuracies there has been a parallel increase in the demand for a CMB reconstruction technique which can provide accurate estimates of CMB signal and the theoretical angular power spectrum along with reliable statistical error estimates associated with them. In this work, we estimate the joint posterior of CMB E mode signal (S) and corresponding theoretical angular power spectrum (C^E_l) over large angular scales given the simulated polarization observations of future generation COrE satellite mission. To generate samples from the joint distribution we employ the ILC technique with prior information of CMB E mode covariance matrix augmented by a Gibbs sampling technique. We estimate the marginalized densities of S and C^E_l using the samples from full-posterior. The best fit cleaned E mode map and the corresponding angular power spectrum agree well with the input E mode map and the sky power spectrum implying accurate reconstruction using COrE like observations. Using the samples C^E_l of all Gibbs chains we estimate the likelihood function P(C^E_l|D) of any arbitrary C^E_l given simulated observed maps (D) of COrE mission following Blackwell-Rao estimator. The likelihood function can be seamlessly integrated to the cosmological parameter estimation method. Apart from producing an accurate estimate of E mode signal over large angular scales our method also builds a connection between the component reconstruction and reliable cosmological parameter estimation using CMB E mode observations over large angular scales. The entire method does not assume any explicit models for E mode foreground components in order to remove them, which is an attractive property since foreground modelling uncertainty does not pose as a challenge in this case.
- [20] arXiv:2004.08536 [pdf, other]
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Title: The fantastic four: V404 Cyg, Cyg X-3, V4641 Sgr and GRS 1915+105 -- Obscured X-ray binariesComments: 24 pages, 14 figures, 8 tables. Accepted for publication in A&A. Abstract slightly abridged to meet ArXiv size limitSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
V404 Cyg, Cyg X-3, V4641 Sgr, and GRS 1915+105 are among the brightest X-ray binaries and display complex behavior in their multiwavelength emission. Apart from Cyg X-3, the other three sources have large accretion disks, and there is evidence of a high orbital inclination. Therefore, any large scale geometrical change in the accretion disk can cause local obscuration events. On the other hand, Cyg X-3 orbits its Wolf-Rayet companion star inside the heavy stellar wind obscuring the X-ray source. We study here whether the peculiar X-ray spectra observed from all four sources can be explained by local obscuration events. We fit the source spectra with two physically motivated models describing either a scenario where all the intrinsic emission is reprocessed in the surrounding matter or where the emitter is surrounded by a thick torus with variable opening angle. We show that the X-ray spectra during specific times are similar in all four sources likely arising from the high-density environments where they are embedded. The fitted models suggest that a low-luminosity phase preceding an intense flaring episode in the 2015 outburst of V404 Cyg is heavily obscured, but intrinsically very bright (super-Eddington) accretion state. Similar spectral evolution to that of V404 Cyg is observed from the recent, unusually low-luminosity state of GRS 1915+105. The modeling results point to a geometry change in the (outflowing) obscuring matter in V404 Cyg and GRS 1915+105, which is also linked to the radio (jet) evolution. All sources display obscured X-ray emission but with different intrinsic luminosities which points towards different factors causing the obscuration. This work highlights the importance of taking into account the reprocessing of the X-ray emission in the surrounding medium in the modeling of the X-ray spectra that may well take place in other sources as well.
- [21] arXiv:2004.08537 [pdf, other]
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Title: Torsional oscillations and magnetic cycles in dynamo models with fluctuationsComments: 12 pages, 9 figuresSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
Using a nonlinear mean-field dynamo model, we study relationships between amplitude of the "extended" mode of migrating zonal flows ("torsional oscillations") and magnetic cycles, and investigate whether the torsional oscillations can be used for solar cycle prediction. We consider two types of dynamo models: models with regular variations of the alpha-effect, and models with stochastic variations. The regular dynamo models show the two different relationships for the growing and decaying stages of the magnetic cycle variations on centennial time scales. For the dynamo models with fluctuations, these relations are merged. We find that for both types of models the amplitude of solar cycles correlates well with the integral amplitude of the zonal harmonic $\ell=9$ of the torsional acceleration waves of the preceding cycles in subsurface layers and with the $\ell=3$ harmonic at the bottom of the convection zone. While these relationships are weaker than the previously known relationship of the cycle magnitude with the poloidal field in the preceding minima, the prediction horizon of the torsional oscillations is greater and may reach the full 11-year activity cycle. In addition, we find that the amplitude of the asymmetric about the equator components of the torsional oscillations can be used as a precursor in forecasts of the hemispheric asymmetry of magnetic activity.
- [22] arXiv:2004.08542 [pdf, other]
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Title: The Polarization Convention of the uGMRT in Band 4Authors: Barnali Das, Sanjay Kudale, Poonam Chandra, Bhaswati Bhattacharya, Jayanta Roy, Yashwant GuptaComments: NCRA internal technical reportSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)
We present an experiment performed to understand the polarization convention adopted for band 4 (550--900 MHz) of the upgraded Giant Metrewave Radio Telescope (uGMRT). For that we observed the pulsar B1702--19 in this band, both in interferometry and pulsar modes, and compare the results with its already known Stokes $I$, $Q$, $U$, $V$ profiles obtained with the Lovell telescope. We find that the results obtained from interferometry and pulsar modes of the uGMRT agree with each other. However, although the Stokes $U$ profile obtained with the uGMRT match with that obtained by the Lovell telescope, Stokes $Q$ and $V$ do not. This can be explained if the $X$ and $Y$ dipoles in this band, from which $R$ and $L$ are derived, are swapped w.r.t. the IAU convention. The swapping makes $RR^*$ and $LL^*$ of the uGMRT band 4 to be $LL^*$ and $RR^*$ respectively according to the IEEE convention. This implies that if we need to compare polarization measurements obtained in band 4 of the uGMRT with telescopes like Lovell, Parkes, Very Large Array etc. (all follow IEEE convention for defining right and left hand circular polarization), we must interchange $RR^*$ and $LL^*$, and change the sign of Stokes $Q$ for the uGMRT data. Note that this is the current convention for uGMRT band 4, and is likely to change in future once the swapping of the dipoles is taken care of. Once it is done, it will be notified in another technical report.
- [23] arXiv:2004.08560 [pdf, ps, other]
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Title: SCUBA-2 overdensities associated with candidate protoclusters selected from Planck dataAuthors: T. Cheng, D. L. Clements, J. Greenslade, J. Cairns, P. Andreani, M. Bremer, L. Conversi, A. Cooray, H. Dannerbauer, G. De Zotti, S. Eales, J. González-Nuevo, E. Ibar, L. Leeuw, J. Ma, M. J. Michałowski, H. Nayyeri, D. A. Riechers, D. Scott, P. Temi, M. Vaccari, I. Valtchanov, E. van Kampen, L. WangComments: 8 pages, 1 figure, 1 table, accepted for publication in MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA)
We measure the 850-$\mu$m source densities of 46 candidate protoclusters selected from the Planck High-z catalogue (PHz) and the Planck Catalogue of Compact Sources (PCCS) that were followed up with Herschel-SPIRE and SCUBA-2. This paper aims to search for overdensities of 850-$\mu$m sources in order to select the fields that are most likely to be genuine protoclusters. Of the 46 candidate protoclusters, 25 have significant overdensities ($>$5 times the field counts), 11 have intermediate overdensities (3--5 times the field counts) and 10 have no overdensity ($<$3 times the field counts) of 850-$\mu$m sources. We find that the enhanced number densities are unlikely to be the result of sample variance. Compared with the number counts of another sample selected from Planck's compact source catalogues, this [PHz+PCCS]-selected sample has a higher fraction of candidate protoclusters with significant overdensities, though both samples show overdensities of 850-$\mu$m sources above intermediate level. Based on the estimated star-formation rate densities (SFRDs), we suggest that both samples can efficiently select protoclusters with starbursting galaxies near the redshift at which the global field SFRD peaks ($2 < z < 3$). Based on the confirmation of overdensities found here, future follow-up observations on other PHz targets may greatly increase the number of genuine DSFG-rich clusters/protoclusters.
- [24] arXiv:2004.08577 [pdf, ps, other]
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Title: The Bright Reverse Shock Emission in the Optical Afterglows of Gamma-ray Bursts in a Stratified MediumComments: Accepted for publication in The Astronomical Journal; 10 pages, 4 figures and 2 tablesSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
The reverse shock (RS) model is generally introduced to interpret the optical afterglows with the rapid rising and decaying, such as the early optical afterglow of GRB 990123 (which is also called optical flash). In this paper, we collected 11 gamma-ray bursts (GRBs) early optical afterglows, which have such signatures of dominant RS emission. Since the temporal slopes of the optical flashes are determined by both the medium density distribution index $k$ and the electron spectral index $p$, we apply the RS model of the thin shell case to the optical flashes and determine the ambient medium of the progenitors. We find that the $k$ value is in the range of 0 - 1.5. The $k$ value in this paper is consistent with the result in Yi et al. (2013), where the forward shock (FS) model was applied to some onset bumps. However, the method adopted in this paper is only applicable to GRB afterglows with significant sharp rising and decaying RS emission. Our results indicate that the RS model can also be applied to confirm the circumburst medium, further implying that GRBs may have diverse circumburst media.
- [25] arXiv:2004.08590 [pdf, other]
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Title: Relative Magnetic Helicity Based on a Periodic Potential FieldComments: 33 pages, 7 figures, accepted by ApJSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
Magnetic helicity is conserved under ideal magnetohydrodynamics (MHD) and quasi-conserved even under a resistive process. The standard definition for magnetic helicity cannot be applied directly to an open magnetic field in a volume, because it is gauge-dependent. Instead, the relative magnetic helicity is widely used. We find that the energy of a potential magnetic field in a rectangular domain with periodic lateral boundary conditions is less than that of the field with a fixed normal component on all six boundaries. To make use of this lower energy potential field in the analysis of relative magnetic helicity, we introducing a new definition for magnetic helicity for the magnetic field, which involves the periodic potential field. We apply this definition to a sequence of analytic solutions and a numerical simulation. The results show that our new gauge-invariant helicity is very close to the current-carrying part of the relative magnetic helicity of the original magnetic field. We find also that the ratio between the current-carrying helicity and the relative magnetic helicity for the original and our defined relative helicity show different behavior. It seems that the new helicity is more sensitive to the component of the field due to the electric current in the volume, which is the source for instabilities and solar eruptive phenomena.
- [26] arXiv:2004.08598 [pdf, other]
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Title: Kinematic analysis of EAGLE simulations: Evolution of $λ_{Re}$ and its connection with mergers and gas accretionAuthors: Daniel Walo-Martín, Jesús Falcón-Barroso, Claudio Dalla Vecchia, Isabel Pérez, Andrea NegriComments: 16 aojes, 9 Figures, accepted MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
We have developed a new tool to analyse galaxies in the EAGLE simulations as close as possible to observations.We investigated the evolution of their kinematic properties by means of the angular momentum proxy parameter,$ \lambda_{Re} $for galaxies with $M_{*} \ge 5 \times 10^{9} M_{\odot}$ in the RefL0100N1504 simulation up to redshift two (z = 2). Galaxies in the simulation show a wide variety of kinematic features, similiar to those found in integral-field spectroscopic studies. At z=0 the distribution of galaxies in the ${\lambda}_{Re}-{\epsilon}$ plane is also in good agreement with results from observations. Scaling relations at z = 0 indicate that there is critical mass, $M_{crit} = 10^{10.3} M_{\odot}$, that divides two different regimes when we include the ${\lambda}_{Re}$ parameter. The simulation shows that the distribution of galaxies in the ${\lambda}_{Re}-{\epsilon}$ plane evolves with time until z = 2 when galaxies are equally distributed both in ${\lambda}_{Re}$ and ${\epsilon}$. We studied the evolution of ${\lambda}_{Re}$ with time and found that there is no connection between the angular momentum at z = 2 and z = 0. All systems reach their maximum ${\lambda}_{Re}$ at z = 1 and then steadily lose angular momentum regardless of their merger history, except for the high star-forming systems that sustain that maximum value over time. The evolution of the Re in galaxies that have not experienced any merger in the last 10 Gyr can be explained by their level of gas accretion.
- [27] arXiv:2004.08632 [pdf]
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Title: Solar physics in the 2020s: DKIST, parker solar probe, and solar orbiter as a multi-messenger constellationAuthors: V. Martinez Pillet, A. Tritschler, L. Harra, V. Andretta, A. Vourlidas, N. Raouafi, B.L. Alterman, L. Bellot Rubio, G. Cauzzi, S.R. Cranmer, S. Gibson, S. Habbal, Y.K. Ko, S.T. Lepri, J. Linker, D.M. Malaspina, S. Matthews, S. Parenti, G. Petrie, D. Spadaro, I. Ugarte-Urra, H. Warren, R. WinslowSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
The National Science Foundation (NSF) Daniel K. Inouye Solar Telescope (DKIST) is about to start operations at the summit of Haleakala (Hawaii). DKIST will join the early science phases of the NASA and ESA Parker Solar Probe and Solar Orbiter encounter missions. By combining in-situ measurements of the near-sun plasma environment and detail remote observations of multiple layers of the Sun, the three observatories form an unprecedented multi-messenger constellation to study the magnetic connectivity inside the solar system. This white paper outlines the synergistic science that this multi-messenger suite enables.
- [28] arXiv:2004.08722 [pdf, other]
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Title: Axion Gamma-Ray Signatures from Quark Matter in Neutron StarsAuthors: Bijan BerenjiSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Phenomenology (hep-ph)
We present a theoretical model for detecting axions from neutron stars in a QCD phase of quark matter, in which the gamma-rays are produced from decaying axions. The axions would be produced from a quark-antiquark pair $u\bar{u}$ or $d\bar{d}$. The axion quark-antiquark coupling can be computed via the Goldberger-Treiman relation, relying on the form factors. A Monte Carlo simulation is used to compute the emissivity for axions, from which the predicted gamma-ray signal from the Fermi Large Area Telescope (Fermi LAT) can be computed. We predict an photon flux which may be detectable by Fermi-LAT. A signal from LIGO could be produced from the neutron star merger as well, which is compared to the expected signal from the Fermi LAT. Very stringent limits on the axion mass of order $10^{-10}$eV could be placed using this model.
- [29] arXiv:2004.08736 [pdf, other]
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Title: New HST data and modeling reveal a massive planetesimal collision around FomalhautComments: 12 pages, 9 figures, accepted to PNASSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
The apparent detection of an exoplanet orbiting Fomalhaut was announced in 2008. However, subsequent observations of Fomalhaut b raised questions about its status: Unlike other exoplanets, it is bright in the optical and nondetected in the infrared, and its orbit appears to cross the debris ring around the star without the expected gravitational perturbations. We revisit previously published data and analyze additional Hubble Space Telescope (HST) data, finding that the source is likely on a radial trajectory and has faded and become extended. Dynamical and collisional modeling of a recently produced dust cloud yields results consistent with the observations. Fomalhaut b appears to be a directly imaged catastrophic collision between two large planetesimals in an extrasolar planetary system. Similar events should be very rare in quiescent planetary systems of the age of Fomalhaut, suggesting that we are possibly witnessing the effects of gravitational stirring due to the orbital evolution of hypothetical planet(s) around the star.
- [30] arXiv:2004.08785 [pdf, other]
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Title: Constraints on Axions from Spatially-Extended Gamma-Ray Emission from Neutron StarsAuthors: Bijan BerenjiComments: Fermi LAT collaborationSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Phenomenology (hep-ph)
Axions are hypothetical particles proposed to solve the strong CP problem in QCD and may constitute a significant fraction of the dark matter in the Universe. Axions are expected to be produced in neutron stars and subsequently decay, producing gamma-rays detectable by the Fermi Large Area Telescope (Fermi-LAT). Considering that light QCD axions, as opposed to axions with mass above 1 eV, may travel a long range before they decay into gamma rays, neutron stars may appear as a spatially-extended source of gamma rays. We extend our previous search for gamma rays from axions, based on a point source model, to consider the neutron star as an extended source of gamma rays. The extended consideration of neutron stars' leads to higher sensitivity to searches for axions.
- [31] arXiv:2004.08804 [pdf, other]
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Title: Constraining MHD disk winds with ALMA. Apparent rotation signatures and application to HH212Authors: B. Tabone, S. Cabrit, G. Pineau des Forêts, J. Ferreira, A. Gusdorf, L. Podio, E. Bianchi, E. Chapillon, C. Codella, F. GuethComments: Accepted for publication in A&ASubjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE)
Large millimeter interferometers are revealing a growing number of rotating outflows, which are suggested to trace magneto-centrifugal disk winds (MHD DWs). However, their impact on disk accretion is not yet well quantified. Here we identify systematic biases in retrieving the true launch zone, magnetic lever arm, and angular momentum flux of an MHD DW from apparent rotation signatures. Synthetic position-velocity cuts are constructed from self-similar MHD DWs over a broad range of parameters, and three different methods are applied for estimating the specific angular momentum. We find that the launch radius inferred using the well-known relation from Anderson et al. (2006) can markedly differ from the true outermost launch radius $r_{out}$ of the DW. The "double-peak separation" and "flow width" methods provide only a strict lower limit to $r_{out}$. This bias is independent of angular resolution and can reach a factor ten. In contrast, the "rotation curve" method gives a good estimate of $r_{out}$ when the flow is well resolved, and an upper limit otherwise. The magnetic lever arm is always underestimated. Only comparison with synthetic predictions can take into account properly all observational effects. As an application, we present a comparison with ALMA observations of HH212 at resolutions from 250 au to 16 au, which represents the most stringent observational test of MHD DW to date. This comparison confirms our predicted biases for the double-peak separation method, and the large $r_{out}\sim40~$au and small magnetic lever arm first suggested by Tabone et al. (2017). We also derive the first accurate analytical expression for the fraction of disk angular momentum extracted by an MHD disk wind of given radial extent, magnetic lever arm, and mass flux. Application to HH212 confirms that MHD DWs are serious candidates for the steady angular momentum extraction process in young disks.
- [32] arXiv:2004.08835 [pdf, other]
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Title: Properties of AGN Multiband Optical Variability in the HSC SSP Transient SurveyAuthors: Yuki Kimura, Toru Yamada, Mitsuru Kokubo, Naoki Yasuda, Tomoki Morokuma, Tohru Nagao, Yoshiki MatsuokaComments: 27 pages, 22 figures. Accepted for publication in ApJSubjects: Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE)
We study variability of active galactic nuclei (AGNs) by using the deep optical multiband photometry data obtained from the Hyper Suprime-Cam Subaru Strategic Program (HSC SSP) survey in the COSMOS field. The images analyzed here were taken with 8, 10, 13, and 15 epochs over three years in the $g$, $r$, $i$, and $z$ bands, respectively. We identified 491 robust variable AGN candidates, down to $i=25$ mag and with redshift up to $4.26$. Ninety percent of the variability-selected AGNs are individually identified with the X-ray sources detected in the Chandra COSMOS Legacy survey. We investigate their properties in variability by using structure function analysis and find that the structure function for low-luminosity AGNs ($L_{\mathrm{bol}}\lesssim10^{45}$ erg s$^{-1}$) shows a positive correlation with luminosity, which is the opposite trend for the luminous quasars. This trend is likely to be caused by larger contribution of the host galaxy light for lower-luminosity AGNs. Using the model templates of galaxy spectra, we evaluate the amount of host galaxy contribution to the structure function analysis and find that dominance of the young stellar population is needed to explain the observed luminosity dependence. This suggests that low-luminosity AGNs at $0.8\lesssim z\lesssim1.8$ are predominantly hosted in star-forming galaxies. The X-ray stacking analysis reveals the significant emission from the individually X-ray undetected AGNs in our variability-selected sample. The stacked samples show very large hardness ratios in their stacked X-ray spectrum, which suggests that these optically variable sources have large soft X-ray absorption by dust-free gas.
- [33] arXiv:2004.08839 [pdf, other]
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Title: New growth mechanism of dust grains in protoplanetary disks with magnetically driven disk windsComments: 21 pages, 9 figures, 1 table, submitted to AAS journalsSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
We discovered a new growth mode of dust grains to km-sized bodies in protoplanetary disks that evolve by viscous accretion and magnetically driven disk winds (MDWs). We solved an approximate coagulation equation of dust grains with time-evolving disks that consist of both gas and solid components by a one dimensional model. With the collisional growth of dust grains, all solid particles initially drift inward toward the central star by the gas drag force. However, the radial profile of gas pressure, $P$, is modified by the MDW that disperses the gas in an inside-out manner. As a result, a local concentration of solid particles is created by the converging radial flux of drifting dust grains at the location with the convex upward profile of $P$. When the dimensionless stopping time, or the Stokes number, St, there exceeds unity, the solid particles spontaneously reach the growth dominated state because of the positive feedback between the suppressed radial drift and the enhanced accumulation of dust particles that drift from the outer part. These consecutive processes proceed even for spherical dust grains under the Epstein gas drag. Once the solid particles are in the drift limited state, the above mentioned condition of St $\gtrsim 1$ for the dust growth is equivalent with \begin{equation}
\Sigma_{\rm d}/\Sigma_{\rm g} \gtrsim \eta, \nonumber \end{equation} where $\Sigma_{\rm d}/\Sigma_{\rm g}$ is the dust-to-gas surface-density ratio and $\eta$ is dimensionless radial pressure-gradient force. As a consequence of the successful growth of dust grains, a ring-like structure containing planetesimal-sized bodies is formed at the inner part of the protoplanetary disks. Such a ring-shaped concentration of planetesimals is expected to play a vital role in the subsequent planet formation. - [34] arXiv:2004.08880 [pdf, ps, other]
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Title: Detection of weak magnetic fields in two HgMn starsAuthors: S. Hubrig, S.P. Jarvinen, H. Korhonen, I. Ilyin, M. Schöller, E. Niemczura, S.D. ChojnowskiComments: 5 pages, 1 table, 3 figures, accepted for publication as MNRAS LetterSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
The main-sequence mercury-manganese (HgMn) stars are known to exhibit large overabundances of exotic elements and, similar to magnetic Ap/Bp stars, are spectrum variables, implying the presence of an inhomogeneous element distribution over the stellar surface. A number of magnetic field studies have been attempted in the last decades, indicating that magnetic fields in HgMn stars, if they exist, should be rather weak. The presence of tangled magnetic fields was suggested by several authors who detected quadratic magnetic fields using the moment technique. We employ the least-squares deconvolution technique to carry out a sensitive search for weak magnetic fields in spectropolarimetric observations of three HgMn stars, HD221507, HD65949, and HD101189, which have different fundamental parameters and spectral characteristics. A definite weak longitudinal field is discovered in HD221507 and HD65949 on single epochs, while only marginal field detections were achieved for HD101189. The new measurements indicate that the structure of the magnetic fields is probably rather complex: our analysis reveals the presence of reversed Stokes V profiles at the same observational epoch if individual elements are used in the measurements. This is the first observational evidence that individual elements sample distinct local magnetic fields of different polarity across the stellar surface.
- [35] arXiv:2004.08923 [pdf, other]
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Title: Short-cadence K2 observations of an accretion-state transition in the polar Tau 4Authors: Colin Littlefield, Peter Garnavich, Paula Szkody, Gavin Ramsay, Steve Howell, Isabel Lima, Mark Kennedy, Lewis CookComments: Submitted to AAS journals. Comments welcomeSubjects: Solar and Stellar Astrophysics (astro-ph.SR); High Energy Astrophysical Phenomena (astro-ph.HE)
The Kepler spacecraft observed a total of only four AM Herculis cataclysmic variable stars during its lifetime. We analyze the short-cadence K2 light curve of one of those systems, Tau 4 (RX J0502.8+1624), which underwent a serendipitous jump from a low-accretion state into a high state during the final days of the observation. Apart from one brief flare, there was no evidence of accretion during the 70 d of observations of the low state. As Tau 4 transitioned into a high state, the resumption of accretion was very gradual, taking approximately six days (~90 binary orbits). We supplement Tau 4's K2 light curve with time-resolved spectroscopy obtained in both high and low states of accretion. High-excitation lines, such as He II 468.6 nm, were extraordinarily weak, even when the system was actively accreting. This strongly suggests the absence of an accretion shock, placing Tau 4 in the bombardment regime predicted for AM Herculis systems with low accretion rates. In both the high-state and low-state spectra, Zeeman absorption features from the white dwarf's photosphere are present and reveal a surface-averaged field strength of $15\pm2$ MG. Remarkably, the high-state spectra also show Zeeman-split emission lines produced in a region with a field strength of $12\pm1$ MG. Zeeman emission has not been previously reported in an AM Herculis system, and we propose that the phenomenon is caused by a temperature inversion in the WD's atmosphere near the accretion region.
- [36] arXiv:2004.08928 [pdf, other]
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Title: Quasi-Hilda Comet 231P/LINEAR-NEAT: Observation at aphelion using Himalayan Chandra Telescope (HCT)Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Comet 231P/LINEAR-NEAT observed around aphelion at 4.88 AU, using 2.0 m Himalayan Chandra Telescope at Mt. Saraswati, Hanle , India. CCD aperture photometry performed and $R_{C}$-band magnitude $21.37\pm 0.08 $ mag obtained. Comet 231P surface brightness profiles compared with field star and found similar, within low level noise in the data; its implicate no cometary activity. We measured dust production levels in term of the quantity $Af\rho$, which was estimated 5.0 cm. Most of the comet observed at perihelion but not aphelion, if we need to calculate total comet dust contribution in the solar system, this type of study may play important role.
- [37] arXiv:2004.08929 [pdf, other]
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Title: Can axion clumps be formed in a pre-inflationary scenario?Comments: 24 pages, 14 figuresSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Theory (hep-th)
The QCD axion and an axion-like particle (ALP) are compelling candidates of dark matter. For the QCD axion, it is known that when the Peccei-Quinn (PQ) symmetry is spontaneously broken after inflation, the large initial fluctuation can lead to axion clump formation. On the other hand, when the symmetry is already broken during inflation, it has been believed that the axion clump formation does not occur due to the small amplitude of the initial axion fluctuation. We revisit this prevailing understanding, considering both the QCD axion and an ALP. We find that for the QCD axion, the clump formation does not occur even if we consider an extremely fine-tuned initial condition. Meanwhile, it turns out that for an ALP which allows a more general potential form, the clump formation can take place through the tachyonic instability or/and the resonance instability, considering a multiple cosine potential.
- [38] arXiv:2004.08970 [pdf, other]
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Title: Coronal Magnetic Field Topology From Total Solar Eclipse ObservationsComments: 18 pages, 11 figures, accepted for publication in ApJSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
Measuring the global magnetic field of the solar corona remains exceptionally challenging. The fine-scale density structures observed in white light images taken during Total Solar Eclipses (TSEs) are currently the best proxy for inferring the magnetic field direction in the corona from the solar limb out to several solar radii (Rs). We present, for the first time, the topology of the coronal magnetic field continuously between 1 and 6 Rs, as quantitatively inferred with the Rolling Hough Transform (RHT) for 14 unique eclipse coronae that span almost two complete solar cycles. We find that the direction of the coronal magnetic field does not become radial until at least 3 Rs, with a high variance between 1.5 and 3 Rs at different latitudes and phases of the solar cycle. We find that the most non-radial coronal field topologies occur above regions with weaker magnetic field strengths in the photosphere, while stronger photospheric fields are associated with highly radial field lines in the corona. In addition, we find an abundance of field lines which extend continuously from the solar surface out to several solar radii at all latitudes, regardless of the presence of coronal holes. These results have implications for testing and constraining coronal magnetic field models, and for linking in situ solar wind measurements to their sources at the Sun.
- [39] arXiv:2004.08972 [pdf]
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Title: The carbon monoxide-rich interstellar comet 2I/BorisovAuthors: D. Bodewits, J. W. Noonan, P. D. Feldman, M. T. Bannister, D. Farnocchia, W. M. Harris, J.-Y. Li, K. E. Mandt, J. Wm. Parker, Z. XingJournal-ref: Nature Astronomy, 2020Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Interstellar comets offer direct samples of volatiles from distant protoplanetary disks. 2I/Borisov is the first notably active interstellar comet discovered in our solar system[1]. Comets are condensed samples of the gas, ice, and dust that were in a star's protoplanetary disk during the formation of its planets and inform our understanding on how chemical compositions and abundances vary with distance from the central star. Their orbital migration moves volatiles[2], organic material, and prebiotic chemicals in their host system[3]. In our solar system, hundreds of comets have been observed remotely, and a few have been studied up close by space missions[4]. However, knowledge of extrasolar comets has been limited to what could be gleaned from distant, unresolved observations of cometary regions around other stars, with only one detection of carbon monoxide[5]. Here we report that the coma of 2I/Borisov contains significantly more CO than H2O gas, with abundances of at least 173%, more than three times higher than previously measured for any comet in the inner (<2.5 au) solar system[4]. Our ultraviolet observations of 2I/Borisov provide the first glimpse into the ice content and chemical composition of the protoplanetary disk of another star that is substantially different from our own.
- [40] arXiv:2004.08979 [pdf, other]
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Title: The duty cycle of radio galaxies revealed by LOFAR: remnant and restarted radio source populations in the Lockman HoleAuthors: Stanislav Shabala, Nika Jurlin, Raffaella Morganti, Marisa Brienza, Martin Hardcastle, Leith Godfrey, Martin Krause, Ross TurnerComments: 14 pages, 7 figures, accepted for publication in MNRAS. Companion paper to Jurlin et al., also in today's arXiv postingSubjects: Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE)
Feedback from radio jets associated with Active Galactic Nuclei (AGN) plays a profound role in the evolution of galaxies. Kinetic power of these radio jets appears to show temporal variation, but the mechanism(s) responsible for this process are not yet clear. Recently, the LOw Frequency ARray (LOFAR) has uncovered large populations of active, remnant and restarted radio jet populations. By focusing on LOFAR data in the Lockman Hole, in this work we use the Radio AGN in Semi-Analytic Environments (RAiSE) dynamical model to present the first self-consistent modelling analysis of active, remnant and restarted radio source populations. Consistent with other recent work, our models predict that remnant radio lobes fade quickly. Any high (>10 percent) observed fraction of remnant and restarted sources therefore requires a dominant population of short-lived jets. We speculate that this could plausibly be provided by feedback-regulated accretion.
- [41] arXiv:2004.09023 [pdf, ps, other]
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Title: The Most Metal-poor Stars in Omega Centauri (NGC 5139)Authors: Christian I. Johnson, Andrea K. Dupree, Mario Mateo, John I. Bailey III, Edward W. Olszewski, Matthew G. WalkerComments: AJ In press; 29 pages, 5 FiguresSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)
The most massive and complex globular clusters in the Galaxy are thought to have originated as the nuclear cores of now tidally disrupted dwarf galaxies, but the connection between globular clusters and dwarf galaxies is tenuous with the M54/Sagittarius system representing the only unambiguous link. The globular cluster Omega Centauri (w Cen) is more massive and chemically diverse than M 54, and is thought to have been the nuclear star cluster of either the Sequoia or Gaia-Enceladus galaxy. Local Group dwarf galaxies with masses equivalent to these systems often host significant populations of very metal-poor stars ([Fe/H] < -2.5), and one might expect to find such objects in w Cen. Using high resolution spectra from Magellan-M2FS, we detected 11 stars in a targeted sample of 395 that have [Fe/H] ranging from -2.30 to -2.52. These are the most metal-poor stars discovered in the cluster, and are 5x more metal-poor than w Cen's dominant population. However, these stars are not so metal-poor as to be unambiguously linked to a dwarf galaxy origin. The cluster's metal-poor tail appears to contain two populations near [Fe/H] ~ -2.1 and -2.4, which are very centrally concentrated but do not exhibit any peculiar kinematic signatures. Several possible origins for these stars are discussed.
- [42] arXiv:2004.09029 [pdf, other]
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Title: The Zwicky Transient Facility Census of the Local Universe I: Systematic search for Calcium rich gap transients reveal three related spectroscopic sub-classesAuthors: Kishalay De, Mansi M. Kasliwal, Anastasios Tzanidakis, U. Christoffer Fremling, Scott Adams, Igor Andreoni, Ashot Bagdasaryan, Eric C. Bellm, Lars Bildsten, Christopher Cannella, David O. Cook, Alexandre Delacroix, Andrew Drake, Dmitry Duev, Alison Dugas, Sara Frederick, Avishay Gal-Yam, Daniel Goldstein, V. Zach Golkhou, Matthew J. Graham, David Hale, Matthew Hankins, George Helou, Anna Y. Q. Ho, Ido Irani, Jacob E. Jencson, Stephen Kaye, S. R. Kulkarni, Thomas Kupfer, Russ R. Laher, Robin Leadbeater, Ragnhild Lunnan, Frank J. Masci, Adam A. Miller, James D. Neill, Eran O. Ofek, Daniel A. Perley, Abigail Polin, Thomas A. Prince, Eliot Quataert, Dan Reiley, Reed L. Riddle, Ben Rusholme, Yashvi Sharma, David L. Shupe, Jesper Sollerman, Leonardo Tartaglia, Richard Walters, Lin Yan, Yuhan YaoComments: 30 figures, 6 tables. Submitted to ApJSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)
(Abridged) Using the Zwicky Transient Facility alert stream, we are conducting a large campaign to spectroscopically classify all transients occurring in galaxies in the Census of the Local Universe (CLU) catalog. The aim of the experiment is to construct a spectroscopically complete, volume-limited sample of transients coincident within 100" of CLU galaxies out to 200 Mpc, and to a depth of 20 mag. We describe the survey design and spectroscopic completeness from the first 16 months of operations. We present results from a systematic search for Calcium rich gap transients in the sample of 22 low luminosity (peak absolute magnitude $M > -17$), hydrogen poor events found in the experiment (out of 754 spectroscopically classified SNe). We report the detection of eight Calcium rich gap transients, and constrain their volumetric rate to be at least $\approx 15\pm5$% of the SN Ia rate. Combining this sample with ten events from the literature, we find a likely continuum of spectroscopic properties ranging from events with SN Ia-like features (Ca-Ia objects) to SN Ib/c-like features (Ca-Ib/c objects) at peak light. Within the Ca-Ib/c events, we find two populations of events distinguished by their red ($g - r \approx 1.5$ mag) or green ($g - r \approx 0.5$ mag) spectral colors at $r$-band peak, wherein redder events show strong line blanketing signatures, slower light curves, weaker He lines and lower [Ca II]/[O I] in the nebular phase. Together, we find that the spectroscopic continuum, volumetric rates and striking old environments are consistent with the explosive burning of He shells on low mass white dwarfs. We posit that Ca-Ia and red Ca-Ib/c objects are consistent with the double detonation of He shells with high He burning efficiency, while green Ca-Ib/c objects could arise from less efficient He burning scenarios such as detonations in low density He shells or He shell deflagrations.
- [43] arXiv:2004.09030 [pdf, ps, other]
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Title: Unbiased Spectroscopic Study of the Cygnus Loop with LAMOST. I. Optical Properties of Emission Lines and the Global SpectrumComments: 22 pages, 11 figures, published in ApJ, figure set available online-onlyJournal-ref: ApJ 893 79 (2020)Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Astrophysics of Galaxies (astro-ph.GA)
We present an unbiased spectroscopic study of the Galactic supernova remnant (SNR) Cygnus Loop using the Large Sky Area Multi-object Fiber Spectroscopic Telescope (LAMOST) DR5. LAMOST features both a large field of view and a large aperture, which allow us to simultaneously obtain 4000 spectra at $\sim$3700-9000 \AA with R$\approx$1800. The Cygnus Loop is a prototype of middle-aged SNRs, which has the advantages of being bright, large in angular size, and relatively unobscured by dust. Along the line of sight to the Cygnus Loop, 2747 LAMOST DR5 spectra are found in total, which are spatially distributed over the entire remnant. This spectral sample is free of the selection bias of most previous studies, which often focus on bright filaments or regions bright in [O III]. Visual inspection verifies that 368 spectra (13$\%$ of the total) show clear spectral features to confirm their association with the remnant. In addition, 176 spectra with line emission show ambiguity of their origin but have a possible association to the SNR. In particular, the 154 spectra dominated by the SNR emission are further analyzed by identifying emission lines and measuring their intensities. We examine distributions of physical properties such as electron density and temperature, which vary significantly inside the remnant, using theoretical models. By combining a large number of the LAMOST spectra, a global spectrum representing the Cygnus Loop is constructed, which presents characteristics of radiative shocks. Finally, we discuss the effect of the unbiased spectral sample on the global spectrum and its implication to understand a spatially unresolved SNR in a distant galaxy.
- [44] arXiv:2004.09067 [pdf, other]
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Title: OGLE-2017-BLG-0406: ${\it Spitzer}$ Microlens Parallax Reveals Saturn-mass Planet orbiting M-dwarf Host in the Inner Galactic DiskAuthors: Yuki Hirao, David P. Bennett, Yoon-Hyun Ryu, Naoki Koshimoto, Andrzej Udalski, Jennifer C. Yee, Takahiro Sumi, Ian A. Bond, Yossi Shvartzvald, Fumio Abe, Richard K. Barry, Aparna Bhattacharya, Martin Donachie, Akihiko Fukui, Yoshitaka Itow, Iona Kondo, Man Cheung Alex Li, Yutaka Matsubara, Taro Matsuo, Shota Miyazaki, Yasushi Muraki, Masayuki Nagakane, Kohji Onishi, Clement Ranc, Nicholas J. Rattenbury, Haruno Suematsu, Hiroshi Shibai, Denis J. Sullivan, Daisuke Suzuki, Paul J. Tristram, Atsunori Yonehara, J. Skowron, R. Poleski, P. Mroz, M.K. Szymanski, I. Soszynski, S. Kozlowski, P. Pietrukowicz, K. Ulaczyk, K. Rybicki, P. Iwanek, Michael D.Albrow, Sun-Ju Chung, Andrew Gould, Cheongho Han, Kyu-Ha Hwang, Youn Kil Jung, In-Gu Shin, Weicheng Zang, Sang-Mok Cha, Dong-Jin Kim, Hyoun-Woo Kim, et al. (46 additional authors not shown)Comments: 40 pages, 12 figures, 10 tables, submitted to AAS journalSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)
We report the discovery and analysis of the planetary microlensing event OGLE-2017-BLG-0406, which was observed both from the ground and by the ${\it Spitzer}$ satellite in a solar orbit. At high magnification, the anomaly in the light curve was densely observed by ground-based-survey and follow-up groups, and it was found to be explained by a planetary lens with a planet/host mass ratio of $q=7.0 \times 10^{-4}$ from the light-curve modeling. The ground-only and ${\it Spitzer}$-"only" data each provide very strong one-dimensional (1-D) constraints on the 2-D microlens parallax vector $\bf{\pi_{\rm E}}$. When combined, these yield a precise measurement of $\bf{\pi_{\rm E}}$, and so of the masses of the host $M_{\rm host}=0.56\pm0.07\,M_\odot$ and planet $M_{\rm planet} = 0.41 \pm 0.05\,M_{\rm Jup}$. The system lies at a distance $D_{\rm L}=5.2 \pm 0.5 \ {\rm kpc}$ from the Sun toward the Galactic bulge, and the host is more likely to be a dusk population star according to the kinematics of the lens. The projected separation of the planet from the host is $a_{\perp} = 3.5 \pm 0.3 \ {\rm au}$, i.e., just over twice the snow line. The Galactic-disk kinematics are established in part from a precise measurement of the source proper motion based on OGLE-IV data. By contrast, the ${\it Gaia}$ proper-motion measurement of the source suffers from a catastrophic $10\,\sigma$ error.
- [45] arXiv:2004.09076 [pdf, other]
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Title: Warming Early Mars with Climate Cycling: The Effect of CO2-H2 Collision-induced AbsorptionAuthors: Benjamin P.C. Hayworth, Ravi Kumar Kopparapu, Jacob Haqq-Misra, Natasha E. Batalha, Rebecca C. Payne, Bradford J. Foley, Mma Ikwut-Ukwa, James F. KastingComments: Publication date July 15 2020Journal-ref: Icarus 345 (2020) 113770Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Explaining the evidence for surface liquid water on early Mars has been a challenge for climate modelers, as the sun was ~30% less luminous during the late-Noachian. We propose that the additional greenhouse forcing of CO2-H2 collision-induced absorption is capable of bringing the surface temperature above freezing and can put early Mars into a limit-cycling regime. Limit cycles occur when insolation is low and CO2 outgassing rates are unable to balance with the rapid drawdown of CO2 during warm weathering periods. Planets in this regime will alternate between global glaciation and transient warm climate phases. This mechanism is capable of explaining the geomorphological evidence for transient warm periods in the martian record. Previous work has shown that collision-induced absorption of CO2-H2 was capable of deglaciating early Mars, but only with high H2 outgassing rates (greater than ~600 Tmol/yr) and at high surface pressures (between 3 to 4 bars). We used new theoretically derived collision-induced absorption coefficients for CO2-H2 to reevaluate the climate limit cycling hypothesis for early Mars. Using the new and stronger absorption coefficients in our 1-dimensional radiative convective model as well as our energy balance model, we find that limit cycling can occur with an H2 outgassing rate as low as ~300 Tmol/yr at surface pressures below 3 bars. Our results agree more closely with paleoparameters for early martian surface pressure and hydrogen abundance.
- [46] arXiv:2004.09077 [pdf, other]
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Title: On the role of reduced wind mass-loss rate in enabling exoplanets to shape planetary nebulaeComments: Will be submitted in two days to allow comments by readersSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Earth and Planetary Astrophysics (astro-ph.EP); Astrophysics of Galaxies (astro-ph.GA)
We use the stellar evolution code MESA-binary and follow the evolution of six exoplanets to determine their potential role in the future evolution of their parent star on the red giant branch (RGB) and on the asymptotic giant branch (AGB). We limit this study to planets with orbits that have semi-major axis of 1AU<a<20AU, a high eccentricity, e>0.25, and having a parent star of mass M>1Mo. We find that the star HIP 75458 will engulf its planet HIP75458 b during its RGB phase. The planet will remove the envelope and terminate the RGB evolution, leaving a bare helium core of mass 0.4Mo that will evolve to form a helium white dwarf. Only in one system out of six, the planet beta Pic c will enter the envelope of its parent star during the AGB phase. For that to occur, we have to reduce the wind mass-loss rate by a factor of about four from its commonly used value. This strengthens an early conclusion, which was based on exoplanets with circular orbits, that states that to have a non-negligible fraction of AGB stars that engulf planets we should consider lower wind mass-loss rates of isolated AGB stars (before they are spun-up by a companion). Such an engulfed planet might lead to the shaping of the AGB mass-loss geometry to form an elliptical planetary nebula.
- [47] arXiv:2004.09109 [pdf, other]
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Title: WASP-4 transit timing variation from a comprehensive set of 129 transitsAuthors: R.V. Baluev, E.N. Sokov, S. Hoyer, C. Huitson, José A.R.S. da Silva, P. Evans, I.A. Sokova, C.R. Knight, V.Sh. ShaidulinComments: Accepted to MNRAS Letters. 5 pages, 1 figure. TTV data files and an online-only PDF supplement are in the download archiveSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM)
We homogeneously reanalyse $124$ transit light curves for the WASP-4 b hot Jupiter. This set involved new observations secured in 2019 and nearly all observations mentioned in the literature, including high-accuracy GEMINI/GMOS transmission spectroscopy of 2011-2014 and TESS observations of 2018. The analysis confirmed a nonlinear TTV trend with $P/|\dot P|\sim (17-30)$ Myr (1-sigma range), implying only half of the initial decay rate estimation. The trend significance is at least $3.4$-sigma in the agressively conservative treatment. Possible radial acceleration due to unseen companions is not revealed in Doppler data covering seven years 2007-2014, and radial acceleration of $-15$ m s$^{-1}$yr$^{-1}$ reported in a recent preprint by another team is not confirmed. If present, it is a very nonlinear RV variation. Assuming that the entire TTV is tidal in nature, the tidal quality factor $Q_\star'\sim (4.5-8.5)\cdot 10^4$ does not reveal a convincing disagreement with available theory predictions.
- [48] arXiv:2004.09113 [pdf, ps, other]
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Title: Position and attitude determination by integrated GPS/SINS/TS for feed support system of FASTComments: 14 pages, 12 figuresJournal-ref: Research in Astronomy and Astrophysics 2020Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)
In this paper, a new measurement system based on integration method is presented,which can provide all-weather dependability and higher precision for the measurement of FAST's feed support system. The measurement system consists of three types of measuring equipments, and a processing software with the core data fusion algorithm. The Strapdown Inertial Navigation System(SINS) can autonomously measure the position, speed and attitude of the carrier. Its own shortcoming is the measurement data diverges rapidly over time. SINS must combine the Global Positioning System(GPS) and the Total Station(TS) to obtain high-precision measurement data. Kalman filtering algorithm is adopted for the integration measurement system, which is an optimal algorithm to estimate the measurement errors. To evaluate the performance, series of tests are carried out. For the feed cabin, the maximum RMS of the position is 14.56mm, the maximum RMS of the attitude is 0.095{\deg}, these value are less than 15mm and 0.1{\deg} as the precision for measuring the feed cabin. For the Stewart manipulator, the maximum RMS of the position is 2.99mm, the maximum RMS of the at titude is 0.093{\deg}, these value are less than 3mm and 0.1{\deg} as the precision for measuring the Stewart manipulator. As a result, the new measurement meets the requirement of measurement precision for FAST's feed support system.
- [49] arXiv:2004.09118 [pdf, other]
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Title: The life cycle of radio galaxies in the LOFAR Lockman Hole fieldAuthors: N. Jurlin, R. Morganti, M. Brienza, S. Mandal, N. Maddox, K. J. Duncan, S. S. Shabala, M. J. Hardcastle, I. Prandoni, H. J. A. Röttgering, V. Mahatma, P. N. Best, B. Mingo, J. Sabater, T. W. Shimwell, C. TasseComments: 16 pages, 9 figures, 4 tables, A&A accepted, companion paper to Shabala et al., also in today arXiv postingSubjects: Astrophysics of Galaxies (astro-ph.GA)
Radio galaxies are known to go through cycles of activity, where phases of apparent quiescence can be followed by repeated activity of the central supermassive black hole. A better understanding of this cycle is crucial for ascertaining the energetic impact that the jets have on the host galaxy, but little is known about it. We used deep LOFAR images at 150 MHz of the Lockman Hole extragalactic field to select a sample of 158 radio sources with sizes $> 60^{\prime\prime}$ in different phases of their jet life cycle. Using a variety of criteria (e.g. core prominence combined with low-surface brightness of the extended emission and steep spectrum of the central region) we selected a subsample of candidate restarted radio galaxies representing between 13% and 15% of the 158 sources of the main sample. We compare their properties to the rest of the sample, which consists of remnant candidates and active radio galaxies. Optical identifications and characterisations of the host galaxies indicate similar properties for candidate restarted, remnant, and active radio galaxies, suggesting that they all come from the same parent population. The fraction of restarted radio galaxies is slightly higher with respect to remnants, suggesting that the restarted phase can often follow after a relatively short remnant phase (the duration of the remnant phase being a few times 10$^{7}$ years). This confirms that the remnant and restarted phases are integral parts of the life cycle of massive elliptical galaxies. A preliminary investigation does not suggest a strong dependence of this cycle on the environment surrounding any given galaxy.
- [50] arXiv:2004.09128 [pdf, ps, other]
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Title: Projection of the gravitational dynamics on a subspace of probability distributions: curl-free Gaussian ansatzAuthors: Patrick ValageasComments: 25 pagesSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
We present a new approach to model the gravitational dynamics of large-scale structures. Instead of solving the equations of motion up to a finite perturbative order or building phenomenological models, we follow the evolution of the probability distribution of the displacement and velocity fields within an approximation subspace. Keeping the exact equations of motion with their full nonlinearity, this provides a nonperturbative scheme that goes beyond shell crossing. Focusing on the simplest case of a curl-free Gaussian ansatz for the displacement and velocity fields, we find that truncations of the power spectra on nonlinear scales directly arise from the equations of motion. This leads to a truncated Zeldovich approximation for the density power spectrum, but with a truncation that is not set a priori and with different power spectra for the displacement and velocity fields. The positivity of their auto power spectra also follows from the equations of motion. Although the density power spectrum is only recovered up to a smooth drift on BAO scales, the predicted density correlation function agrees with numerical simulations within $2\%$ from BAO scales down to $7 h^{-1} {\rm Mpc}$ at $z \geq 0.35$, without any free parameter.
- [51] arXiv:2004.09142 [pdf, ps, other]
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Title: The Lyman Alpha Reference Sample XI: Efficient Turbulence Driven Lyα Escape and the Analysis of IR, CO and [C II]158 μmAuthors: J. Puschnig, M. Hayes, G. Östlin, J. Cannon, I. Smirnova-Pinchukova, B. Husemann, D. Kunth, J. Bridge, E. C. Herenz, M. Messa, I. OteoSubjects: Astrophysics of Galaxies (astro-ph.GA)
We study the global dust and (molecular) gas content in the Lyman Alpha Reference Sample (LARS), i.e. 14 local star-forming galaxies. We characterize their interstellar medium and relate newly derived properties to quantities relevant for Ly$\alpha$ escape. We observed LARS galaxies with Herschel/PACS, SOFIA/FIFI-LS, the IRAM 30m telescope and APEX, targeting far-infrared (FIR) continuum and emission lines of [C II]158$\mu$m, [O I]63$\mu$m, [O III]88$\mu$m and low-J CO lines. Using Bayesian methods we derive dust model parameters and estimate total gas masses for all LARS galaxies, taking into account a metallicity-dependent gas-to-dust ratio. Star formation rates were estimated from FIR, [C II]158$\mu$m and [O I]63$\mu$m luminosities. LARS covers a wide dynamic range in the derived properties, with FIR-based star formation rates from $\sim$0.5-100 $M_{\odot}\ yr^{-1}$, gas fractions between $\sim$15-80% and gas depletion times ranging from a few hundred Myr up to more than 10 Gyr. The distribution of LARS galaxies in the $\Sigma_{gas}$ vs. $\Sigma_{SFR}$ (Kennicutt-Schmidt plane) is thus quite heterogeneous. However, we find that LARS galaxies with the longest gas depletion times, i.e. relatively high gas surface densities ($\Sigma_{gas}$) and low star formation rate densities ($\Sigma_{SFR}$), have by far the highest Ly$\alpha$ escape fraction. A strong $\sim$linear relation is found between Ly$\alpha$ escape fraction and the total gas (HI+H$_2$) depletion time. We argue that the Ly$\alpha$ escape in those galaxies is driven by turbulence in the star-forming gas that shifts the Ly$\alpha$ photons out of resonance close to the places where they originate. We further report on an extreme [C II]158$\mu$m excess in LARS 5, corresponding to $\sim$14$\pm$3% of the FIR luminosity, i.e. the most extreme [C II]-to-FIR ratio observed in a non-AGN galaxy to date.
- [52] arXiv:2004.09149 [pdf, other]
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Title: On the distribution of fluxes of gamma-ray blazars: hints for a stochastic process?Comments: 7 pages, 4 figures, submitted to MNRASSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
We examine a model for the observed temporal variability of powerful blazars in the $\gamma$-ray band in which the dynamics is described in terms of a stochastic differential equation, including the contribution of a deterministic drift and a stochastic term. The form of the equation is motivated by the current astrophysical framework, accepting that jets are powered through the extraction of the rotational energy of the central supermassive black hole mediated by magnetic fields supported by a so-called \emph{magnetically arrested} accretion disk. We apply the model to the $\gamma$-ray light curves of several bright blazars and we infer the parameters suitable to describe them. In particular, we examine the differential distribution of fluxes ($dN/dF_{\gamma}$) and we show that the predicted probability density function for the assumed stochastic equation naturally reproduces the observed power law shape at large fluxes $dN/dF_{\gamma} \propto F_{\gamma}^{-\alpha}$ with $\alpha>2$.
- [53] arXiv:2004.09150 [pdf, other]
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Title: Candidate fossil groups in the CFHTLS: a probabilistic approachComments: 9 pages, 4 figures, A&A acceptedSubjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
Fossil groups (FGs) have been discovered twenty-five years ago, and are now defined as galaxy groups with an X-ray luminosity higher than $10^{42}\ h_{50}^{-2}$ erg s$^{-1}$ and a brightest group galaxy brighter than the other group members by at least 2 magnitudes. However, the scenario of their formation remains controversial. We propose here a probabilistic analysis of FGs, extracted from the large catalogue of candidate groups and clusters detected by Sarron et al. (2018) in the CFHTLS survey, based on photometric redshifts, to investigate their position in the cosmic web and probe their environment. Based on spectroscopic and photometric redshifts, we estimate the probability of galaxies to belong to a galaxy structure, and by imposing the condition that the brightest group galaxy is at least brighter than the others by 2 magnitudes, we compute the probability for a given galaxy structure to be a FG. We analyse the mass distribution of these candidate FGs, and estimate their distance to the filaments and nodes of the cosmic web in which they are embedded. We find that the structures with masses lower than $2.4\times 10^{14}$ M$_\odot$ have the highest probabilities of being fossil groups (PFG). Overall, structures with PFG$\geq$50% are located close to the cosmic web filaments (87% are located at less than 1 Mpc from their nearest filament). They are preferentially four times more distant from their nearest node than from their nearest filament. We confirm that FGs have small masses and are rare. They seem to reside closeby cosmic filaments and do not survive in nodes. Being in a poor environment could therefore be the driver of FG formation, the number of nearby galaxies not being sufficient to compensate for the cannibalism of the central group galaxy.
- [54] arXiv:2004.09176 [pdf, other]
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Title: The magnetic sensitivity of the resonance and subordinate lines of Mg II in the solar chromosphereJournal-ref: 2020, The Astrophysical Journal, Volume 891, Issue 1, id.91Subjects: Solar and Stellar Astrophysics (astro-ph.SR)
We carry out a theoretical study of the polarization of the solar Mg II h-k doublet (including its extended wings) and the subordinate UV triplet around 280 nm. These lines are of great diagnostic interest, as they encode information on the physical properties of the solar atmosphere from the upper photosphere to the chromosphere-corona transition region. We base our study on radiative transfer calculations of spectral line polarization in one-dimensional models of quiet and plage regions of the solar atmosphere. Our calculations take into account the combined action of atomic polarization, quantum level interference, frequency redistribution, and magnetic fields of arbitrary strength. In particular, we study the sensitivity of the emergent Stokes profiles to changes in the magnetic field through the Zeeman and Hanle effects. We also study the impact of the chromospheric plasma dynamics on the emergent Stokes profiles, taking into account the angle-dependent frequency redistribution in the h-k resonance transitions. The results presented here are of interest for the interpretation of spectropolarimetric observations in this important region of the solar ultraviolet spectrum.
- [55] arXiv:2004.09206 [pdf, other]
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Title: Predicting 21cm-line map from Lyman $α$ emitter distribution with Generative Adversarial NetworksComments: 15 pages, 11 figures, 3 tables, submitted to MNRASSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
The radio observation of 21cm-line signal from the Epoch of Reionization (EoR) enables us to explore the evolution of galaxies and intergalactic medium in the early universe. However, the detection and imaging of 21cm-line signal are tough due to the foreground and instrumental systematics. In order to overcome these obstacles, as a new approach, we propose to take a cross correlation between observed 21cm-line data and 21cm-line images generated from the distribution of the Lyman-$\alpha$ emitters (LAEs) through machine learning. In order to create 21cm-line maps from LAE distribution, we apply conditional Generative Adversarial Network (cGAN) trained with the results of our numerical simulations. We find that 21cm-line brightness temperature maps and the neutral fraction maps can be well reproduced at large scales. Furthermore, we show that the cross correlation is detectable at $k < 0.2~{\rm Mpc}^{-1}$ by combing 400 hours of MWA Phase II observation and LAE deep survey of the Subaru Hyper Suprime Camera. Our new approach of cross correlation with image construction using the cGAN can not only boost the detectability of EoR 21cm-line signal but also allow us to estimate the 21cm-line auto-power spectrum.
- [56] arXiv:2004.09213 [pdf, other]
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Title: The Cherenkov Telescope ArrayAuthors: Jürgen Knödlseder (for the CTA Consortium)Comments: 8 pages, 5 figures, Proceedings of Theory meeting experiments (TMEX 2020), 16th Rencontres du VietnamSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); High Energy Astrophysical Phenomena (astro-ph.HE)
The Cherenkov Telescope Array (CTA) is the observatory for ground-based gamma-ray astronomy that will shape the domain of TeV astronomy for the next decades. CTA will comprise more than 100 imaging air Cherenkov telescopes deployed on two sites, one in the northern hemisphere on La Palma and one in the southern hemisphere in Chile. A large fraction of CTA's observing time will be apportioned through a competitive proposal-driven time allocation scheme that is open to the scientific community. Hence CTA will become an astronomical tool that complements other large ground- and space-based observatories that do and will exist at other wavelengths and for other messengers. In this contribution I will present the CTA Observatory, its main characteristics, and the current status of the construction project. First light was already obtained by prototype CTA telescopes and cameras, and deployment of the CTA arrays will start soon. The science analysis software is already in good shape, and available to the wider community for preparing CTA science and data analysis.
- [57] arXiv:2004.09288 [pdf, other]
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Title: An alternative interpretation of GW190412 as a binary black hole merger with a rapidly spinning secondarySubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); General Relativity and Quantum Cosmology (gr-qc)
The LIGO-Virgo collaboration recently reported the properties of GW190412, a binary black hole merger with unequal component masses (mass ratio $0.25^{+0.06}_{-0.04}$ when using the EOBNR PHM approximant) and a non-vanishing effective spin aligned with the orbital angular momentum. They used ad hoc priors to infer that the more massive black hole had a dimensionless spin magnitude between 0.17 and 0.59 at 90% confidence. We argue that, within the context of isolated binary evolution, it is more natural to assume a priori that the first-born, more massive black hole has a negligible spin, while the spin of the less massive black hole is preferentially aligned with the orbital angular momentum if it is spun up by tides. Under this astrophysically motivated prior, we conclude that the lower mass black hole had a dimensionless spin component between 0.67 and 0.99 along the orbital angular momentum.
- [58] arXiv:2004.09291 [pdf, other]
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Title: Investigating the relationship between cosmic curvature and dark energy models with the latest supernova sampleComments: 9 pages, 2 figures, 1 table, submitted to RAASubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
We investigate the relationship between the cosmic curvature and the model of dark energy (hereafter DE) with the recent Type Ia supernovae (hereafter SNe Ia) data, i.e., the Pantheon sample including 1048 SNe Ia with $0.01 < z < 2.3$. We obtain the measurements of the dimensionless spatial curvature density today, i.e., $\Omega_{k0} = -0.062^{+0.189}_{-0.169}, -0.004^{+0.228}_{-0.134}, 0.127^{+0.280}_{-0.276}$ and $0.422^{+0.213}_{-0.338}$ at 68\% confidence level (CL), respectively, in the scenarios of $\Lambda$CDM, $\phi$CDM (i.e., scalar field dark energy), $\omega$CDM and $\omega_0\omega_a$CDM models. In the scenario of $\Lambda$CDM model, a closed universe is preferred by the Pantheon sample, which is consistent with that from the Planck CMB spectra. However, the uncertainty of $\Omega_{k0}$ from the Pantheon SNe sample is about 8 times larger than that from the Planck data, so the former one supports a closed universe at a much lower CL than that from the latter one. An open unverse is supported by the Pantheon sample at $\sim$32\% and $\sim$78\% CLs, respectively, in the $\omega$CDM and $\omega_0\omega_a$CDM models. Among these models, the $\phi$CDM model is the one which supports the flat universe most strongly. It shows that $\Omega_{k0}$ is significantly dependent on the adopted model of dark energy, and there is a negative correlation between $\Omega_{k0}$ and the equation of state of DE.
- [59] arXiv:2004.09328 [pdf, other]
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Title: Gaussian Decomposition of λ21-cm Interstellar HI profilesComments: 15 pages, 10 figuresSubjects: Astrophysics of Galaxies (astro-ph.GA)
Following an established protocol of science, that results must be reproducible, we examine the Gaussian fits to Galactic 21-cm emission profiles obtained by two seemingly complementary methods: the semi-automated approach based on the method used by Verschuur (2004) and the automated technique of Nidever et al. (2008). Both methods use data from the Leiden/Argentine/Bonn all-sky survey. The appeal of an automated routine is great, if for no other reason than the time saved over semi-automated fits. The pitfalls, however, are often unanticipated, and the most important aspect of any algorithm is the reproducibility of the results. The comparisons led to the identification of four problems with the Nidever et al. (2008) analysis: (1) different methods of calculating the reduced chi-squared measuring the goodness of fit; (2) an ultra-broad component found bridging the gap between low and intermediate velocity gas; (3) the lack of an imposed spatial coherence allowing different components to appear and disappear in profiles separated by a fraction of a beam width; and (4) multiple, fundamentally different solutions for the profiles at both the North and South Galactic Poles. A two-step method would improve the algorithm, where an automated fit is followed by a quality-assurance, visual inspection. Confirming evidence emerges from this study of a pervasive component with a line width of order 34 km/s, which may be explained by the Critical Ionization Velocity (CIV) of helium. Since the Nidever et al. (2008) paper contains the only result in the refereed literature that contradicts the CIV model, it is important to understand the flaws in the analysis that let to this contradiction.
- [60] arXiv:2004.09356 [pdf, other]
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Title: Searching for obscured AGN in z $\sim$ 2 submillimetre galaxiesAuthors: H. Chen, M. A. Garrett, S. Chi, A. P. Thomson, P. D. Barthel, D. M. Alexander, T. W. B. Muxlow, R. J. Beswick, J. F. Radcliffe, N. H. Wrigley, D. Guidetti, M. Bondi, I. Prandoni, I. Smail, I. McHardy, M. K. ArgoComments: 11 pages, 5 figuresSubjects: Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE)
Submillimetre-selected galaxies (SMGs) at high redshift ($z$ $\sim$ 2) are potential host galaxies of active galactic nuclei (AGN). If the local Universe is a good guide, $\sim$ 50$\%$ of the obscured AGN amongst the SMG population could be missed even in the deepest X-ray surveys. Radio observations are insensitive to obscuration; therefore, very long baseline interferometry (VLBI) can be used as a tool to identify AGN in obscured systems. A well-established upper limit to the brightness temperature of 10$^5$ K exists in star-forming systems, thus VLBI observations can distinguish AGN from star-forming systems via brightness temperature measurements. We present 1.6 GHz European VLBI Network (EVN) observations of four SMGs (with measured redshifts) to search for evidence of compact radio components associated with AGN cores. For two of the sources, e-MERLIN images are also presented. Out of the four SMGs observed, we detect one source, J123555.14, that has an integrated EVN flux density of 201 $\pm$ 15.2 $\mu$Jy, corresponding to a brightness temperature of 5.2 $\pm$ 0.7 $\times$ 10$^5$ K. We therefore identify that the radio emission from J123555.14 is associated with an AGN. We do not detect compact radio emission from a possible AGN in the remaining sources (J123600.10, J131225.73, and J163650.43). In the case of J131225.73, this is particularly surprising, and the data suggest that this may be an extended, jet-dominated AGN that is resolved by VLBI. Since the morphology of the faint radio source population is still largely unknown at these scales, it is possible that with a $\sim$ 10 mas resolution, VLBI misses (or resolves) many radio AGN extended on kiloparsec scales.
- [61] arXiv:2004.09359 [pdf, other]
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Title: A 4-6 GHz Radio Recombination Line Survey in the Milky WayComments: 24 pages, 19 figuresSubjects: Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)
We performed a radio recombination line (RRL) survey to construct a high-mass star-forming region (HMSFR) sample in the Milky Way based on the all-sky Wide-Field Infrared Survey Explorer ($\textit{All-WISE}$) point source catalog. The survey was observed with the Shanghai 65m Tianma radio telescope (TMRT) covering 10 hydrogen RRL transitions ranging from H98$\alpha$ to H113$\alpha$ (corresponding to the rest frequencies of 4.5$-$6.9 GHz) simultaneously. Out of 3348 selected targets, we identified an HMSFR sample consisting of 517 sources traced by RRLs, a large fraction of this sample (486) locate near the Galactic plane ($|$$\textit{b}$$|$ $<$ 2 deg). In addition to the hydrogen RRLs, we also detected helium and carbon RRLs towards 49 and 23 sources respectively. We cross-match the RRL detections with the 6.7 methanol maser sources built up in previous works for the same target sample, as a result, 103 HMSFR sources were found to harbor both emissions. In this paper, we present the HMSFR catalog accompanied by the measured RRL line properties and a correlation with our methanol maser sample, which is believed to tracer massive stars at earlier stages. The construction of an HMSFR sample consisting of sources in various evolutionary stages indicated by different tracers is fundamental for future studies of high-mass star formation in such regions.
- [62] arXiv:2004.09361 [pdf, other]
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Title: Stress mirror polishing for future large lightweight mirrors: design using shape optimizationAuthors: Sabri Lemared, Marc Ferrari, Christian Du Jeu, Thibault Dufour, Nathalie Soulier, Emmanuel HugotComments: 18 pages, 17 figuresSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)
This study proposes a new way to manufacture large lightweight aspherics for space telescopes using Stress Mirror Polishing (SMP). This technique is well known to allow reaching high quality optical surfaces in a minimum time period, thanks to a spherical full-size polishing tool. To obtain the correct surface' aspheric shape, it is necessary to define precisely the thickness distribution of the mirror to be deformed, according to the manufacturing parameters. We first introduce active optics and Stress Mirror Polishing techniques, and then, we describe the process to obtain the appropriate thickness mirror distribution allowing to generate the required aspheric shape during polishing phase. Shape optimization procedure using PYTHON programing and NASTRAN optimization solver using Finite Element Model (FEM) is developed and discussed in order to assist this process. The main result of this paper is the ability of the shape optimization process to support SMP technique to generate a peculiar aspherical shape from a spherical optical surface thanks to a thickness distribution reshaping. This paper is primarily focused on a theoretical framework with numerical simulations as the first step before the manufacturing of a demonstrator. This two-steps approach was successfully used for previous projects.
- [63] arXiv:2004.09369 [pdf, other]
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Title: A Massive Molecular Torus inside a Gas-Poor Cirnumnuclear Disk in the Radio Galaxy NGC 1052 Discovered with ALMAAuthors: Seiji Kameno, Satoko Sawada-Satoh, C. M. Violette Impellizzeri, Daniel Espada, Naomasa Nakai, Hajime Sugai, Yuichi Terashima, Kotaro Kohno, Minju Lee, Sergio MartínComments: Accepted for publication in ApJ, 27 pages, 13 figures, 7 tablesSubjects: Astrophysics of Galaxies (astro-ph.GA)
We report ALMA observations of NGC 1052 to quest mass accretion in a gas-poor active galactic nucleus (AGN). We detected CO emission representing a rotating ring-like circumnuclear disk (CND) seen edge-on with the gas mass of $5.3 \times 10^{5}$ M$_{\odot}$. The CND has smaller gas mass than that in typical Seyfert galaxies with circumnuclear star formation and is too gas-poor to drive mass accretion onto the central engine. The continuum emission casts molecular absorption features of CO, HCN, HCO$^+$, SO, SO$_2$, CS, CN, and H$_2$O, with H$^{13}$CN and HC$^{15}$N and vibrationally-excited (v$_2 = 1$) HCN and HCO$^+$. Broader absorption line widths than CND emission line widths imply presence of a geometrically thick molecular torus with a radius of $2.4 \pm 1.3$ pc and a thickness ratio of $0.7 \pm 0.3$. We estimate the H$_2$ column density of $(3.3 \pm 0.7) \times 10^{25}$ cm$^{-2}$ using H$^{12}$CN, H$^{13}$CN, and HCO$^{+}$ absorption features and adopting abundance ratio of $^{12}$C-to-$^{13}$C and a HCO$^{+}$-to-H$_2$, and derived the torus gas mass of $(1.3 \pm 0.3) \times 10^7$ M$_{\odot}$, which is $\sim 9$\% of the central black-hole mass. The molecular gas in the torus is clumpy with the estimated covering factor of $0.17^{+0.06}_{-0.03}$. The gas density of clumps inside the torus is inferred to be $(6.4 \pm 1.3) \times 10^7$ cm$^{-3}$, which meets the excitation conditions of H$_2$O maser. Specific angular momentum in the torus exceeds a flat-rotation curve extrapolated from that of the CND, indicating a Keplerian rotation inside a 14.4-pc sphere of influence.
- [64] arXiv:2004.09371 [pdf, ps, other]
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Title: Complex phase masks for fabricating OH-suppression filters for astronomyComments: 4 Pages, 4 figures, to be submitted to IEEE Photonics Technology LettersSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)
The design of a complex phase mask (CPM) for inscribing aperiodic filters in fibers is presented. The complex structure of the mask surface relief consists of discrete aperiodic phase-steps at periodic intervals. We show that the diffraction of the inscribing laser beam from the phase-step locations of the CPM produces periodically located half phase-steps along the fiber. The accumulated phase, along with controlled index modulation, generates the desired aperiodic reflection spectrum. Compared to a complex 'running-light' interferometry based inscription method, CPM offers the well known convenience and reproducibility of the standard phase mask inscription technique. The complexity of an aperiodic grating is encoded into the structure of the CPM. Complex filters fabricated with CPM can be used for suppressing the near infrared (NIR) OH- emission lines generated in the upper atmosphere, improving the performance of ground based telescopes.
- [65] arXiv:2004.09378 [pdf, other]
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Title: Feasibility of superwinds-generated ultrahigh-energy cosmic rays upon the light of large-scale modeling of starburstsComments: 7 pages revote, 2 .pdf figuresSubjects: Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE)
The Pierre Auger Collaboration has provided a compelling indication for a possible correlation between the arrival directions of ultrahigh-energy cosmic rays and nearby starburst galaxies. Herein we show how the latest large-scale modeling of starburst galaxies is compatible with the cosmic rays producing the anisotropy signal being accelerated at the terminal shock of superwinds.
- [66] arXiv:2004.09382 [pdf, ps, other]
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Title: Open Clusters as Tracers on Radial Migration of the Galactic DiskComments: 10 pages, 12 figures,accepted by MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)
Radial migration is an important process in the Galactic disk. A few open clusters show some evidence on this mechanism but there is no systematic study. In this work, we investigate the role of radial migration on the Galactic disk based on a large sample of 146 open clusters with homogeneous metallicity and age from Netopil et al. and kinematics calculated from Gaia DR2. The birth site Rb, guiding radius Rg and other orbital parameters are calculated, and the migration distance |Rg-Rb| is obtained, which is a combination of metallicity, kinematics and age information. It is found that 44% open clusters have |Rg-Rb|< 1 kpc, for which radial migration (churning) is not significant. Among the remaining 56% open clusters with |Rg-Rb|> 1 kpc, young ones with t<1.0 Gyr tend to migrate inward, while older clusters usually migrate outward. Different mechanisms of radial migration between young and old clusters are suggested based on their different migration rates, Galactic locations and orbital parameters. For the old group, we propose a plausible way to estimate migration rate and obtain a reasonable value of 1.5(+-0.5) kpc/Gyr based on ten intermediate-age clusters at the outer disk, where the existence of several special clusters implies its complicate formation history.
- [67] arXiv:2004.09391 [pdf, other]
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Title: Mapping the working of environmental effects in A963Authors: Boris Deshev, Christopher Haines, Ho Seong Hwang, Alexis Finoguenov, Rhys Taylor, Ivana Orlitova, Maret Einasto, Bodo ZieglerComments: A&A accepted. 14 pages, 15 figuresSubjects: Astrophysics of Galaxies (astro-ph.GA)
We qualitatively assess and map the relative contribution of pre-processing and cluster related processes to the build-up of A963, a massive cluster at z=0.2 showing an unusually high fraction of star forming galaxies in its interior. We use Voronoi binning of positions of cluster members on the plane of the sky in order to map the 2D variations of galaxy properties in the centre and infall region of A963. We map four galaxy parameters (fraction of star forming galaxies, specific star formation rate, HI deficiency and age of the stellar population) based on full SED fitting, 21cm imaging and optical spectroscopy. We find an extended region dominated by passive galaxies along a north-south axis crossing the cluster centre, possibly associated with known filaments of the large-scale structure. There are signs that the passive galaxies in this region were quenched long before their arrival in the vicinity of the cluster. Contrary to that, to the east and west of the cluster centre lie regions of recent accretion dominated by gas rich, actively star forming galaxies not associated with any substructure or filament. The few passive galaxies in this region appear to be recently quenched, and some gas rich galaxies show signs of ongoing ram-pressure stripping. We report the first tentative observations at 21cm of ongoing ram-pressure stripping at z=0.2, as well as observed inflow of low-entropy gas into the cluster along filaments of the large-scale structure. The observed galaxy content of A963 is a result of strongly anisotropic accretion of galaxies with different properties. Gas rich, star forming galaxies are being accreted from the east and west of the cluster and these galaxies are being quenched at r<R200, while the bulk of the accretion, containing multiple groups, happens along the north-south axis and brings mostly passive galaxies.
- [68] arXiv:2004.09394 [pdf, ps, other]
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Title: AGN X-ray irradiation of CO gas in NGC 2110 revealed by $Chandra$ and ALMAAuthors: Taiki Kawamuro, Takuma Izumi, Kyoko Onishi, Masatoshi Imanishi, Dieu D. Nguyen, Shunsuke BabaComments: 15 pages, 11 figures, 3 tables. Accepted for publication in ApJSubjects: Astrophysics of Galaxies (astro-ph.GA)
We report spatial distributions of the Fe-K$\alpha$ line at 6.4 keV and the CO($J$ = 2--1) line at 230.538 GHz in NGC 2110, which are respectively revealed by $Chandra$ and ALMA at $\approx$ 0.5 arcsec. A $Chandra$ 6.2--6.5 keV-to-3.0--6.0 keV image suggests that the Fe-K$\alpha$ emission extends preferentially in a northwest-to-southeast direction out to $\sim$ 3 arcsec, or 500 pc, on each side. Spatially-resolved spectral analyses support this by finding significant Fe-K$\alpha$ emission lines only in northwest and southeast regions. Moreover, their equivalent widths are found $\sim$ 1.5 keV, indicative for the fluorescence by nuclear X-ray irradiation as the physical origin. By contrast, CO($J$ = 2--1) emission is weak therein. For quantitative discussion, we derive ionization parameters by following an X-ray dominated region (XDR) model. We then find them high enough to interpret the weakness as the result of X-ray dissociation of CO and/or H$_2$. Another possibility also remains that CO molecules follow a super-thermal distribution, resulting in brighter emission in higher-$J$ lines. Further follow-up observations are encouraged to draw a conclusion on what predominantly changes the inter-stellar matter properties, and whether the X-ray irradiation eventually affects the surrounding star formation as an AGN feedback.
- [69] arXiv:2004.09396 [pdf, other]
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Title: Search for the imprint of axion-like particles in the highest-energy photons of hard $γ$-ray blazarsComments: 23 pages, 8 figures, 2 tablesSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
Axion-like particles (ALPs), predicted in theories beyond the Standard Model, can have observational effects on the transparency of the Universe to $\gamma$ rays in the presence of magnetic fields. In this work, we search for effects compatible with the existence of ALPs with 80 months of data from the ${\it Fermi}$ Large Area Telescope, by comparing the distributions of observed highest energy photons from sources beyond redshifts of z $\geq$ 0.1 with theoretical predictions in the presence of ALPs. We find no evidence for an increased $\gamma$-ray transparency due to ALPs and therefore we set limits on the ALPs parameters assuming a value of the intergalactic magnetic field strength of 1 nG. Photon-ALP couplings above $10^{-11}$ GeV$^{-1}$ are excluded for ALP masses $m_{a}$ $\lesssim3.0$ neV. These limits exclude a region of the parameter space not covered by other $\gamma$-ray telescopes and are compatible with constraints imposed by other experiments.
- [70] arXiv:2004.09401 [pdf, other]
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Title: Galaxy Cluster Contribution to the Diffuse Extragalactic Ultraviolet BackgroundComments: 9 pages, 4 figures. Accepted for publication in AJSubjects: Astrophysics of Galaxies (astro-ph.GA)
The diffuse ultraviolet background radiation has been mapped over most of the sky with 2\arcmin \ resolution using data from the \textit{GALEX} survey. We utilize this map to study the correlation between the UV background and clusters of galaxies discovered via the Sunyaev-Zeldovich effect in the \textit{Planck} survey. We use only high Galactic latitude ($|b| > 60^{\circ} $) galaxy clusters to avoid contamination by Galactic foregrounds, and we only analyze clusters with a measured redshift. This leaves us with a sample of 142 clusters over the redshift range $0.02 \leq z \leq 0.72$, which we further subdivide into four redshift bins. In analysing our stacked samples binned by redshift, we find evidence for a central excess of UV background light compared to local backgrounds for clusters with $z<0.3$. We then stacked these $z<0.3$ clusters to find a statistically significant excess of $12 \pm 2.3$ photon cm$^{-2}$ s${-1}$ sr$^{-1}$ \AA $^{-1}$ \ over the median of $\sim 380$ photon cm$^{-2}$ s${-1}$ sr$^{-1}$ \AA $^{-1}$ \ measured around random blank fields. We measure the stacked radial profile of these clusters, and find that the excess UV radiation decays to the level of the background at a radius of $\sim 1$ Mpc, roughly consistent with the maximum radial extent of the clusters. Analysis of possible physical processes contributing to the excess UV brightness indicates that non-thermal emission from relativistic electrons in the intracluster medium and faint, unresolved UV emission from cluster member galaxies and intracluster light are likely the dominant contributors.
- [71] arXiv:2004.09415 [pdf, ps, other]
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Title: Omega Centauri: weak MgH-band in red giants directly trace the helium contentAuthors: Arumalla B. S. Reddy (Indian Institute of Astrophysics, Koramangala, Bangalore, India)Comments: 20 pages, 13 figures, 6 tables, accepted for publication in MNRASSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)
High spectral resolution and high signal-to-noise ratio optical spectra of red giants in the globular cluster Omega Centauri are analysed for stellar parameters and chemical abundances of 15 elements including helium by either line equivalent widths or synthetic spectrum analyses. The simultaneous abundance analysis of MgH and Mg lines adopting theoretical photospheres and a combination of He/H$-$ratios proved to be the only powerful probe to evaluate helium abundances of red giants cooler than 4400 K, wherein otherwise helium line transitions (He {\scs I} 10830 and 5876 \AA) present for a direct spectral line analysis. The impact of helium-enhanced model photospheres on the resulting abundance ratios are smaller than 0.15 dex, in agreement with past studies. The first indirect spectroscopic helium abundances measured in this paper for the most metal-rich cluster members reveal the discovery of seven He-enhanced giants ($\Delta$$Y=+$0.15$\pm$0.04), the largest such sample found spectroscopically to date. The average metallicity of $-$0.79$\pm$0.06 dex and abundances for O, Na, Al, Si, Ca, Ti, Ni, Ba, and La are consistent with values found for the red giant branch (RGB-a) and subgiant branch (SGB-a) populations of Omega Centauri, suggesting an evolutionary connection among samples. The He-enhancement in giants is associated with larger $s$-process elemental abundances, which correlate with Al and anticorrelate with O. These results support the formation of He-enhanced, metal-rich population of Omega Centauri out of the interstellar medium enriched with the ejecta of fast rotating massive stars, binaries exploding as supernovae and asymptotic giant branch (AGB) stars.
- [72] arXiv:2004.09431 [pdf, other]
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Title: AT 2016dah and AT 2017fyp: the first classical novae discovered within a tidal streamAuthors: M. J. Darnley, A. M. Newsam, K. Chinetti, I. D. W. Hawkins, A. L. Jannetta, M. M. Kasliwal, J. C. McGarry, M. M. Shara, M. Sitaram, S. C. WilliamsComments: 22 pages, 14 figures, 4 tables. Accepted for publication in MNRASSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE)
AT2016dah and AT2017fyp are fairly typical Andromeda Galaxy (M31) classical novae. AT2016dah is an almost text book example of a 'very fast' declining, yet uncommon, Fe II'b' (broad-lined) nova, discovered during the rise to peak optical luminosity, and decaying with a smooth broken power-law light curve. AT2017fyp is classed as a 'fast' nova, unusually for M31, its early decline spectrum simultaneously shows properties of both Fe II and He/N spectral types - a 'hybrid'. Similarly, the light curve of AT2017fyp has a broken power-law decline but exhibits an extended flat-topped maximum. Both novae were followed in the UV and X-ray by the Neil Gehrels Swift Observatory, but no X-ray source was detected for either nova. The pair were followed photometrically and spectroscopically into their nebular phases. The progenitor systems were not visible in archival optical data, implying that the mass donors are main sequence stars. What makes AT2016dah and AT2017fyp particularly interesting is their position with respect to M31. The pair are close on the sky but are located far from the centre of M31, lying almost along the semi-minor axis of their host. Radial velocity measurements and simulations of the M31 nova population leads to the conclusion that both novae are members of the Andromeda Giant Stellar Stream (GSS). We find the probability of at least two M31 novae appearing coincident with the GSS by chance is ~1%. Therefore, we claim that these novae arose from the GSS progenitor, not M31 - the first confirmed novae discovered in a tidal steam.
- [73] arXiv:2004.09433 [pdf, other]
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Title: Analysis of the galaxy size versus stellar mass relationAuthors: J. Sanchez Almeida (1,2) ((1) Instituto de Astrofisica de Canarias, La Laguna, Tenerife, Spain, (2) Departamento de Astrofisica, Universidad de La Laguna, Spain)Comments: Accepted for publication in MNRAS. 11 figures. 12 pagesSubjects: Astrophysics of Galaxies (astro-ph.GA)
The scatter in the galaxy size versus stellar mass (Mstar) relation gets largely reduced when, rather than the half-mass radius Re, the size at a fixed surface density is used. Here we address why this happens. We show how a reduction is to be expected because any two galaxies with the same Mstar have at least one radius with identical surface density, where the galaxies have identical size. However, the reason why the scatter is reduced to the observed level is not trivial, and we pin it down to the galaxy surface density profiles approximately following Sersic profiles with their Re and Sersic index (n) anti-correlated (i.e., given Mstar, n increases when Re decreases). Our analytical results describe very well the behavior of the observed galaxies as portrayed in the NASA Sloan Atlas (NSA), which contains more than half a million local objects with 7 < log(Mstar/Msun) < 11.5. The comparison with NSA galaxies also allows us to find the optimal values for the mass surface density (2.4m0.9p1.3 Msun/pc2) and surface brightness (r-band 24.7pm0.5 mag/arcsec2) that minimize the scatter, although the actual values depend somehow on the subset of NSA galaxies used for optimization. The physical reason for the existence of optimal values is unknown but, as Trujillo+20 point out, they are close to the gas surface density threshold to form stars and thus may trace the physical end of a galaxy. Our NSA-based size--mass relation agrees with theirs on the slope as well as on the magnitude of the scatter. As a by-product of the narrowness of the size--mass relation (only 0.06 dex), we propose to use the size of a galaxy to measure its stellar mass. In terms of observing time, it is not more demanding than the usual photometric techniques and may present practical advantages in particular cases.
- [74] arXiv:2004.09438 [pdf, other]
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Title: The formation of young massive clusters by colliding flowsComments: 6 pages, 5 figures, accepted for publication in MNRAS LettersSubjects: Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)
Young massive clusters (YMCs) are the most intense regions of star formation in galaxies. Formulating a model for YMC formation whilst at the same time meeting the constraints from observations is highly challenging however. We show that forming YMCs requires clouds with densities $\gtrsim$ 100 cm$^{-3}$ to collide with high velocities ($\gtrsim$ 20 km s$^{-1}$). We present the first simulations which, starting from moderate cloud densities of $\sim100$ cm$^{-3}$, are able to convert a large amount of mass into stars over a time period of around 1 Myr, to produce dense massive clusters similar to those observed. Such conditions are commonplace in more extreme environments, where YMCs are common, but atypical for our Galaxy, where YMCs are rare.
- [75] arXiv:2004.09482 [pdf, other]
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Title: Quantifying the effects of spatial resolution and noise on galaxy metallicity gradientsAuthors: Ayan Acharyya, Mark R. Krumholz, Christoph Federrath, Lisa J. Kewley, Nathan J. Goldbaum, Rob SharpComments: 21 pages, 11 figures, 20 pages Supplementary Online Material provided with 10 additional figures, accepted for publication in MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA)
Metallicity gradients are important diagnostics of galaxy evolution, because they record the history of events such as mergers, gas inflow and star-formation. However, the accuracy with which gradients can be measured is limited by spatial resolution and noise, and hence measurements need to be corrected for such effects. We use high resolution (~20 pc) simulation of a face-on Milky Way mass galaxy, coupled with photoionisation models, to produce a suite of synthetic high resolution integral field spectroscopy (IFS) datacubes. We then degrade the datacubes, with a range of realistic models for spatial resolution (2 to 16 beams per galaxy scale length) and noise, to investigate and quantify how well the input metallicity gradient can be recovered as a function of resolution and signal-to-noise ratio (SNR) with the intention to compare with modern IFS surveys like MaNGA and SAMI. Given appropriate propagation of uncertainties and pruning of low SNR pixels, we show that a resolution of 3-4 telescope beams per galaxy scale length is sufficient to recover the gradient to ~10-20% uncertainty. The uncertainty escalates to ~60% for lower resolution. Inclusion of the low SNR pixels causes the uncertainty in the inferred gradient to deteriorate. Our results can potentially inform future IFS surveys regarding the resolution and SNR required to achieve a desired accuracy in metallicity gradient measurements.
- [76] arXiv:2004.09487 [pdf, other]
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Title: Relieving the Hubble tension with primordial magnetic fieldsComments: 7 pages (including supplemental material in the appendix), 3 figures, 1 tableSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Phenomenology (hep-ph)
The standard cosmological model determined from the accurate cosmic microwave background measurements made by the Planck satellite implies a value of the Hubble constant $H_0$ that is $4.4$ standard deviations lower than the one determined from Type Ia supernovae. The Planck best fit model also predicts higher values of the matter density fraction $\Omega_m$ and clustering amplitude $S_8$ compared to those obtained from the Dark Energy Survey Year 1 data. Here we show that accounting for the enhanced recombination rate due to additional small-scale inhomogeneities in the baryon density may solve both the $H_0$ and the $S_8-\Omega_m$ tensions. The additional baryon inhomogeneities can be induced by primordial magnetic fields present in the plasma prior to recombination. The required field strength to solve the Hubble tension is just what is needed to explain the existence of galactic, cluster, and extragalactic magnetic fields without relying on dynamo amplification. Our results show clear evidence for this effect and motivate further detailed studies of primordial magnetic fields, setting several well-defined targets for future observations.
Cross-lists for Tue, 21 Apr 20
- [77] arXiv:2004.05974 (cross-list from gr-qc) [pdf, other]
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Title: Recognizing black holes in gravitational-wave observations: Telling apart impostors in mass-gap binariesSubjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Astrophysical Phenomena (astro-ph.HE)
We show how by careful monitoring of the inspiral signal from a compact object binary in ground-based gravitational wave (GW) detectors one can test if its components are black holes or not. Here we limit ourselves to black holes (with and without spin) in General Relativity. Such objects are characterized by horizons, which absorb gravitational radiation from the orbit during their inspiral in a binary, via a phenomenon known as tidal heating. By contrast, a compact object such as a neutron star has minimal tidal heating -- but has tidal deformation -- and affects the phase evolution of binaries containing it in a distinctly different way. Here we identify waveform parameters that characterize the strength of tidal heating, and are zero when there is no horizon absorption. We demonstrate how by using those parameters Bayesian methods can distinguish the presence or absence of horizons in a binary. This is a particularly exciting prospect owing to several claims that these stellar-mass objects, with masses heavier than those of neutron stars, may not have a horizon but may be black hole mimickers or exotic compact objects. Perhaps more significant is the possibility that our method can be used to test the presence or absence of horizons in mass-gap binaries and, thereby, help detect the heaviest neutron star or the lightest black hole. A proper accounting of tidal heating in binary waveform models will also be critical for an unbiased measurement of characteristics of the equation of state of neutron stars in GW observations of binaries containing them -- or even to probe the existence of exotic compact objects.
- [78] arXiv:2004.06713 (cross-list from physics.flu-dyn) [pdf, other]
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Title: Turbulent drag reduction in magnetohydrodynamic and quasi-static magnetohydrodynamic turbulenceComments: To appear in Phys. Plasmas. arXiv admin note: text overlap with arXiv:1904.11167Subjects: Fluid Dynamics (physics.flu-dyn); Solar and Stellar Astrophysics (astro-ph.SR); Geophysics (physics.geo-ph); Plasma Physics (physics.plasm-ph)
In hydrodynamic turbulence, the kinetic energy injected at large scales cascades to the inertial range, leading to a constant kinetic energy flux. In contrast, in magnetohydrodynamic (MHD) turbulence, a fraction of kinetic energy is transferred to the magnetic energy. Consequently, for the same kinetic energy injection rate, the kinetic energy flux in MHD turbulence is reduced compared to its hydrodynamic counterpart. This leads to relative weakening of the nonlinear term ($\la | ({\bf u}\cdot \nabla) {\bf u} | \ra$, where ${\bf u}$ is the velocity field) and turbulent drag, but strengthening of the velocity field in MHD turbulence. We verify the above using shell model simulations of hydrodynamic and MHD turbulence. Quasi-static MHD turbulence too exhibits turbulent drag reduction similar to MHD turbulence.
- [79] arXiv:2004.08111 (cross-list from gr-qc) [pdf, other]
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Title: Primordial Black Holes from Pre-Big Bang inflationComments: 25 pages, two figuresSubjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Theory (hep-th)
We discuss the possibility of producing a significant fraction of dark matter in the form of primordial black holes in the context of the pre-big bang inflationary scenario. We take into account, to this purpose, the enhancement of curvature perturbations possibly induced by a variation of the sound-speed parameter $c_s$ during the string phase of high-curvature inflation. After imposing all relevant observational constraints, we find that the considered class of models is compatible with the production of a large amount of primordial black holes in the mass range relevant to dark matter, provided the sound-speed parameter is confined in a rather narrow range of values, $0.003 < c_s < 0.01$.
- [80] arXiv:2004.08394 (cross-list from hep-ph) [pdf, other]
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Title: Measuring Changes in the Atmospheric Neutrino Rate Over Gigayear TimescalesAuthors: Johnathon R. Jordan, Sebastian Baum, Patrick Stengel, Alfredo Ferrari, Maria Cristina Morone, Paola Sala, Joshua SpitzComments: 6 pages, 2 figuresSubjects: High Energy Physics - Phenomenology (hep-ph); Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE); Instrumentation and Methods for Astrophysics (astro-ph.IM); High Energy Physics - Experiment (hep-ex); Instrumentation and Detectors (physics.ins-det)
Measuring the cosmic ray flux over timescales comparable to the age of the solar system, $\sim 4.5\,$Gyr, could provide a new window on the history of the Earth, the solar system, and even our galaxy. We present a technique to indirectly measure the rate of cosmic rays as a function of time using the imprints of atmospheric neutrinos in paleo-detectors, natural minerals which record damage tracks from nuclear recoils. Minerals commonly found on Earth are $\lesssim 1\,$Gyr old, providing the ability to look back across cosmic ray history on timescales of the same order as the age of the solar system. Given a collection of differently aged samples dated with reasonable accuracy, this technique is particularly well-suited to measuring historical changes in the cosmic ray flux at Earth and is broadly applicable in astrophysics and geophysics.
- [81] arXiv:2004.08399 (cross-list from hep-ph) [pdf, other]
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Title: Constraints on the coupling with photons of heavy axion-like-particles from Globular ClustersAuthors: Pierluca Carenza (Bari Univ. & INFN Bari), Oscar Straniero (INAF), Babette Döbrich (CERN), Maurizio Giannotti (Barry Univ.), Giuseppe Lucente (Bari Univ.), Alessandro Mirizzi (Bari Univ. & INFN Bari)Comments: 8 pages, 5 figuresSubjects: High Energy Physics - Phenomenology (hep-ph); Solar and Stellar Astrophysics (astro-ph.SR); High Energy Physics - Experiment (hep-ex)
We update the globular cluster bound on massive ($m_a$ up to a few 100 keV) axion-like particles (ALP) interacting with photons. The production of such particles in the stellar core is dominated by the Primakoff $\gamma + Ze\to Ze +a$ and by the photon coalescence process $\gamma+\gamma\to a$. The latter, which is predominant at high masses, was not included in previous estimations. Consequently, our result strengthens the previous constraints considerably, especially for $m_a \gtrsim 50$ keV. The combined constraints from Globular Cluster stars, SN 1987A, and beam-dump experiments leave a small triangularly shaped region open in the parameter space around $m_a \sim 0.5-1\,$ MeV and $g_{a\gamma} \sim 10^{-5}$ GeV$^{-1}$. This is informally known as the ALP "cosmological triangle" since it can be excluded only using standard cosmological arguments. As we shall discuss, however, there are viable cosmological models that are compatible with axion-like particles with parameters in such region. We also discuss possibilities to explore the cosmological triangle experimentally in upcoming accelerator experiments.
- [82] arXiv:2004.08403 (cross-list from gr-qc) [pdf, other]
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Title: Fifth force induced by a chameleon field on nested cylindersComments: Submitted to Phys. Rev. DSubjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
This article investigates the properties of a scalar fifth force that arises in a scalar tensor-theory with a chameleon screening mechanism in the context of gravity space missions like the MICROSCOPE experiment. In such an experiment, the propagation of the chameleon field inside the nested cylinders of the experiment causes a fifth force when the cylinders are not perfectly co-axial. We propose a semi-analytic method to compute the field distribution and the induced fifth force and compare it to a full numerical simulation, in settings where the cylindrical symmetry is broken. The scaling of the fifth force with both the parameters of the model and the geometry of the experiment is discussed. We show that the fifth force is repulsive, hence adds a destabilizing stiffness that should be included in the force budget acting on the detector. This opens the way to a new method to constrain a scalar fifth force in screened models.
- [83] arXiv:2004.08404 (cross-list from hep-ph) [pdf, ps, other]
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Title: Reheating and Post-inflationary Production of Dark MatterComments: 15 pages, 5 figuresSubjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
We perform a systematic analysis of dark matter production during post-inflationary reheating. Following the period of exponential expansion, the inflaton begins a period of damped oscillations as it decays. These oscillations and the evolution of temperature of the thermalized decay products depend on the shape of the inflaton potential $V(\Phi)$. We consider potentials of the form $\Phi^k$. Standard matter dominated oscillations occur for $k=2$. In general, the production of dark matter may depend on either (or both) the maximum temperature after inflation, or the reheating temperature, where the latter is defined when the universe becomes radiation dominated. We show that dark matter production is sensitive to the inflaton potential and depends heavily on the maximum temperature when $k>2$. We also consider the production of dark matter with masses larger than the reheating temperature.
- [84] arXiv:2004.08464 (cross-list from gr-qc) [pdf, other]
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Title: Global Analysis of the Gravitational Wave Signal from Galactic BinariesComments: 17 pages, 13 figures, submitted to PRDSubjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Astrophysical Phenomena (astro-ph.HE); Instrumentation and Methods for Astrophysics (astro-ph.IM)
Galactic ultra compact binaries are expected to be the dominant source of gravitational waves in the milli-Hertz frequency band. Of the tens of millions of galactic binaries with periods shorter than an hour, it is estimated that a few tens of thousand will be resolved by the future Laser Interferometer Space Antenna (LISA). The unresolved remainder will be the main source of ``noise'' between 1-3 milli-Hertz. Typical galactic binaries are millions of years from merger, and consequently their signals will persist for the the duration of the LISA mission. Extracting tens of thousands of overlapping galactic signals and characterizing the unresolved component is a central challenge in LISA data analysis, and a key contribution to arriving at a global solution that simultaneously fits for all signals in the band. Here we present an end-to-end analysis pipeline for galactic binaries that uses trans-dimensional Bayesian inference to develop a time-evolving catalog of sources as data arrive from the LISA constellation.
- [85] arXiv:2004.08866 (cross-list from cs.AI) [pdf, other]
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Title: Space Debris Ontology for ADR Capture Methods SelectionAuthors: Marko Jankovic (1), Mehmed Yüksel (1), Mohammad Mohammadzadeh Babr (1), Francesca Letizia (2), Vitali Braun (2) ((1) Robotics Innovation Center (RIC)--DFKI GmbH and University of Bremen, (2) IMS Space Consultancy for the European Space Operation Center (ESOC)--ESA)Comments: 32 pages, 7 figures and 6 tablesJournal-ref: Acta Astronautica, Volume: 173, Year: 2020, Pages: 56-68, ISSN: 0094-5765Subjects: Artificial Intelligence (cs.AI); Instrumentation and Methods for Astrophysics (astro-ph.IM); Space Physics (physics.space-ph)
Studies have concluded that active debris removal (ADR) of the existing in-orbit mass is necessary. However, the quest for an optimal solution does not have a unique answer and the available data often lacks coherence. To improve this situation, modern knowledge representation techniques, that have been shaping the World Wide Web, medicine and pharmacy, should be employed. Prior efforts in the domain of space debris have only focused onto space situational awareness, neglecting ADR. To bridge this gap we present a domain-ontology of intact derelict objects, i.e. payloads and rocket bodies, for ADR capture methods selection. The ontology is defined on a minimal set of physical, dynamical and statistical parameters of a target object. The practicality and validity of the ontology are demonstrated by applying it onto a database of 30 representative objects, built by combining structured and unstructured data from publicly available sources. The analysis of results proves the ontology capable of inferring the most suited ADR capture methods for considered objects. Furthermore, it confirms its ability to handle the input data from different sources transparently, minimizing user input. The developed ontology provides an initial step towards a more comprehensive knowledge representation framework meant to improve data management and knowledge discovery in the domain of space debris. Furthermore, it provides a tool that should make the initial planning of future ADR missions simpler yet more systematic.
- [86] arXiv:2004.08884 (cross-list from gr-qc) [pdf, ps, other]
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Title: $f(R)$ Gravity $k$-Essence Late-time PhenomenologyComments: PDU AcceptedSubjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Theory (hep-th)
In this work we shall study the late-time behavior of $k$-Essence $f(R)$ gravity without scalar potential, in the presence of matter and radiation perfect fluids. We quantify the late-time study by using the statefinder function $Y_H(z)=\frac{\rho_{DE}}{\rho_m^{(0)}}$, which is a function of the redshift and of the Hubble rate. By appropriately rewriting the Friedmann equation in terms of the redshift and of the function $Y_H(z)$, we numerically solve it using appropriate initial conditions, and we critically examine the effects of the $k$-Essence higher order kinetic terms. As we demonstrate, the effect of the higher order scalar field kinetic terms on the late-time dynamics is radical, since the dark energy oscillations are absent, and in addition, the cosmological physical quantities are compatible with the latest Planck data and also the model is almost indistinguishable from the $\Lambda$ Cold Dark Matter model. This is in contrast to the standard $f(R)$ gravity case, where the oscillations are present. Furthermore, by choosing a different set of values of two of the free parameters of the model, and specifically the coefficient of the higher order kinetic term and of the exponent of $R^{\delta}$ appearing in the $f(R)$ action, we demonstrate that it is possible to obtain $\rho_{DE}<0$ for redshifts $z\sim 2-3.8$, which complies phenomenologically with, and seems to explain, the observational data for the same redshifts, and also to obtain a viable cosmological evolution at $z\sim 0$, at least when the dark energy equation of state parameter and the dark energy density parameters are considered.
- [87] arXiv:2004.09053 (cross-list from physics.flu-dyn) [pdf, other]
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Title: Euler Turbulence and thermodynamic equilibriumComments: 5 pagesSubjects: Fluid Dynamics (physics.flu-dyn); Solar and Stellar Astrophysics (astro-ph.SR); Statistical Mechanics (cond-mat.stat-mech); Chaotic Dynamics (nlin.CD)
We perform a unique direct numerical simulation of Euler turbulence using delta-correlated velocity field as an initial condition, and report a full range of $k^2$ and $k$ energy spectra for 3D and 2D flows respectively, zero energy flux, and Maxwell-Boltzmann distribution for the velocity field. These are direct verification of the predictions of the absolute equilibrium theory of turbulence. For a coherent vortex as an initial condition, Euler turbulence transitions from a mixture of nonequilibrium-equilibrium state to a equilibrium state through a process called thermalization. In this letter, we present a model for thermalization in Euler turbulence.
- [88] arXiv:2004.09339 (cross-list from gr-qc) [pdf, ps, other]
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Title: Vacua in novel 4D Eisntein-Gauss-Bonnet Gravity: pathology and instabilityAuthors: Fu-Wen ShuComments: 6 pages, 1 figureSubjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Theory (hep-th)
We show an inconsistence of the novel 4D Einstein-Gauss-Bonnet gravity by considering a quantum tunneling process of vacua. Using standard semi-classical techniques, we analytically study the vacuum decay rate for all allowed cases in the parameter space. It turns out, without exception, that the theory either encounters a disastrous divergence of vacuum decay rate, or exhibits a confusing complex value of vacuum decay rate, or involves an infinitely instability (a large vacuum mixing). These suggest a strong possibility that the theory, at least the vacuum of the theory, is either unphysical or unstable, or has no well-defined limit as $D\rightarrow 4$.
- [89] arXiv:2004.09384 (cross-list from gr-qc) [pdf, other]
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Title: Suppressed cosmic growth in coupled vector-tensor theoriesComments: 24 pages, 3 figuresSubjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Theory (hep-th)
We study a coupled dark energy scenario in which a massive vector field $A_{\mu}$ with broken $U(1)$ gauge symmetry interacts with the four-velocity $u_c^{\mu}$ of cold dark matter (CDM) through the scalar product $Z=-u_c^{\mu} A_{\mu}$. This new coupling corresponds to the momentum transfer, so that the background vector and CDM continuity equations do not have explicit interacting terms analogous to the energy exchange. Hence the observational preference of uncoupled generalized Proca theories over the $\Lambda$CDM model can be still maintained at the background level. Meanwhile, the same coupling strongly affects the evolution of cosmological perturbations. While the effective sound speed of CDM vanishes, the propagation speed and no-ghost condition of a longitudinal scalar of $A_{\mu}$ and the CDM no-ghost condition are subject to nontrivial modifications by the $Z$ dependence in the Lagrangian. We propose a concrete dark energy model and show that the gravitational interaction on scales relevant to the linear growth of large-scale structures can be smaller than the Newton constant at low redshifts. This leads to the suppression of growth rates of both CDM and total matter density perturbations, so our model allows an interesting possibility for reducing the tension of matter density contrast $\sigma_8$ between high- and low-redshift measurements.
- [90] arXiv:2004.09390 (cross-list from gr-qc) [pdf, other]
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Title: The three body first post-Newtonian effects on the secular dynamics of a compact binary near a spinning supermassive black holeComments: 10 pages, 3 figuresSubjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Astrophysical Phenomena (astro-ph.HE)
The binary black holes (BBHs) formed near the supermassive black holes (SMBHs) in the galactic nuclei would undergo eccentricity excitation due to the gravitational perturbations from the SMBH and therefore merger more efficiently. In this paper, we study the coupling of the three body 1st post-Newtonian (pN) effects with the spin effects from the SMBH in the hierarchical triple system. The three body 1pN effects yielding the de-Sitter precession is usually decoupled in the secular dynamics, while it couples to the spin of SMBH through the Lense-Thirring precession of the outer orbital plane. This coupling includes both the precessions of the inner orbit angular momentum and the Runge-Lenz vector around the outer orbit angular momentum in a general reference frame. Our general argument on the coupling of the three body 1pN effects in three body systems could be extended to any other situation as long as the outer orbital plane evolves.
Replacements for Tue, 21 Apr 20
- [91] arXiv:1410.8076 (replaced) [pdf, other]
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Title: Conformal theory of gravitation and cosmologyAuthors: R. K. Nesbet (IBM Almaden Research Center)Comments: 7 pagesSubjects: General Physics (physics.gen-ph); Astrophysics of Galaxies (astro-ph.GA)
- [92] arXiv:1802.04251 (replaced) [pdf, other]
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Title: Constraining Bianchi Type I Universe With Type Ia Supernova and H(z) DataComments: 11 pages,9 figures, 5tablesSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [93] arXiv:1810.00165 (replaced) [pdf, other]
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Title: Thermodynamics of Surface-Bounded ExospheresAuthors: Norbert SchorghoferComments: 7 pages, 1 figure, preprintSubjects: Earth and Planetary Astrophysics (astro-ph.EP)
- [94] arXiv:1811.05400 (replaced) [pdf, other]
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Title: Recovering $Λ$CDM Model From a Cosmographic StudyComments: 13 pages, 13 figures, 5 tablesJournal-ref: General Relativity and Gravitation, 52, 13 (2020)Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [95] arXiv:1812.08356 (replaced) [pdf, other]
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Title: Dark Matter Distribution of Four Low-z Clusters of GalaxiesComments: 29 pages, 18 figuresSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [96] arXiv:1904.11505 (replaced) [pdf, other]
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Title: The Rise and Fall of the King: The Correlation between FO Aquarii's Low States and the White Dwarf's SpindownAuthors: Colin Littlefield, Peter Garnavich, Mark R. Kennedy, Joseph Patterson, Jonathan Kemp, Robert A. Stiller, Franz-Josef Hambsch, Teofilo Arranz Heras, Gordon Myers, Geoffrey Stone, George Sjoberg, Shawn Dvorak, Peter Nelson, Velimir Popov, Michel Bonnardeau, Tonny Vanmunster, Enrique de Miguel, Kevin B. Alton, Barbara Harris, Lewis M. Cook, Keith A. Graham, Stephen M. Brincat, David J. Lane, James Foster, Roger Pickard, Richard Sabo, Brad Vietje, Damien Lemay, John Briol, Nathan Krumm, Michelle Dadighat, William Goff, Rob Solomon, Stefano Padovan, Greg Bolt, Emmanuel Kardasis, Andre Debackere, Jeff Thrush, William Stein, Daniel Coulter, Valery Tsehmeystrenko, Jean-Francois Gout, Pablo Lewin, Charles Galdies, David Cejudo Fernandez, Gary Walker, James Boardman Jr., Emil PellettComments: Accepted for publication in ApJSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
- [97] arXiv:1904.12875 (replaced) [pdf, other]
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Title: Three-Dimensional Simulations of Magnetar-Powered Superluminous SupernovaeComments: Accepted to ApJ, 12 pagesSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
- [98] arXiv:1905.03352 (replaced) [pdf, other]
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Title: Flare Energy Release at the Magnetic Field Polarity Inversion Line During M1.2 Solar Flare of 2015 March 15. II. Investigation of Photospheric Electric Current and Magnetic Field Variations Using HMI 135-second Vector MagnetogramsSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
- [99] arXiv:1905.04706 (replaced) [pdf, ps, other]
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Title: Probing low-mass WIMP candidates of dark matter with tetrafluoroethane superheated liquid detectorsComments: Major revisions: title and abstract slightly changed; method of estimating the bubble nucleation thresholds reformulated; main qualitative conclusions remain unchanged; Latex 27 pages, 9 figures; new references added; matches version accepted for publication in PRDSubjects: High Energy Physics - Phenomenology (hep-ph); Astrophysics of Galaxies (astro-ph.GA)
- [100] arXiv:1908.11325 (replaced) [pdf, ps, other]
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Title: Dark Matter Constraints on Low Mass and Weakly Coupled B-L Gauge BosonComments: 24 pages, 7 figures, revision with the indirect dark matter constraintsSubjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Experiment (hep-ex)
- [101] arXiv:1909.01400 (replaced) [pdf, other]
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Title: Quasar X-ray and UV flux, baryon acoustic oscillation, and Hubble parameter measurement constraints on cosmological model parametersComments: 14 pages, 12 figuresJournal-ref: Mon.Not.Roy.Astron.Soc. 492 (2020) no.3, 4456Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Experiment (hep-ex); High Energy Physics - Phenomenology (hep-ph)
- [102] arXiv:1909.03006 (replaced) [pdf, other]
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Title: Evaluation of Automated Fermi GBM Localizations of Gamma-ray BurstsAuthors: Adam Goldstein, Corinne Fletcher, Peter Veres, Michael S. Briggs, William H. Cleveland, Melissa H. Gibby, C. Michelle Hui, Elisabetta Bissaldi, Eric Burns, Rachel Hamburg, Andreas von Kienlin, Daniel Kocevski, Bagrat Mailyan, Christian Malacaria, William S. Paciesas, Oliver J. Roberts, Colleen A. Wilson-HodgeComments: Accepted for publication in ApJ. Added Appendix showing localization comparisons for each GRB in the near-realtime public reporting sampleSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); High Energy Astrophysical Phenomena (astro-ph.HE)
- [103] arXiv:1909.04262 (replaced) [pdf, ps, other]
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Title: ALMA Observations of Giant Molecular Clouds in M33 I: Resolving Star Formation Activities in the Giant Molecular Filaments Possibly Formed by a Spiral ShockAuthors: Kazuki Tokuda, Kazuyuki Muraoka, Hiroshi Kondo, Atsushi Nishimura, Tomoka Tosaki, Sarolta Zahorecz, Sachiko Onodera, Rie E. Miura, Kazufumi Torii, Nario Kuno, Shinji Fujita, Hidetoshi Sano, Toshikazu Onishi, Kazuya Saigo, Yasuo Fukui, Akiko Kawamura, Kengo TachiharaComments: 12 pages, 5 figures, Accepted for publication in ApJSubjects: Astrophysics of Galaxies (astro-ph.GA)
- [104] arXiv:1910.00459 (replaced) [pdf, other]
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Title: Quintessence Axion Dark Energy and a Solution to the Hubble TensionComments: 4 pages, 3 figures, version published in PLBJournal-ref: Phys. Lett. B 805 (2020) 135408Subjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [105] arXiv:1910.03636 (replaced) [pdf, other]
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Title: Reconstructing Functions and Estimating Parameters with Artificial Neural Networks: A Test with the Hubble Parameter and SNe IaComments: 15 pages, 16 figures, and 1 table, match publication version. The code repository is available at \href{this https URL}{this https URL}Journal-ref: Astrophys.J.Suppl. 246 (2020) no.1, 13Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Instrumentation and Methods for Astrophysics (astro-ph.IM); Data Analysis, Statistics and Probability (physics.data-an)
- [106] arXiv:1910.04097 (replaced) [pdf, ps, other]
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Title: Less noticeable shallow decay phase in early X-ray afterglows of GeV/TeV-detected gamma-ray burstsComments: 12 pages, 6 figures, 3 tables. MNRAS, in pressSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
- [107] arXiv:1910.04901 (replaced) [pdf, other]
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Title: Dodelson-Widrow Mechanism In the Presence of Self-Interacting NeutrinosComments: 6 pages, 5 figures, equations fixed, results and conclusions unchangedJournal-ref: Phys. Rev. Lett. 124, 081802 (2020)Subjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [108] arXiv:1910.13235 (replaced) [pdf, other]
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Title: Constant roll and primordial black holesComments: 10 pages, 8 figures, updated to match published versionJournal-ref: JCAP 03 (2020) 002Subjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Theory (hep-th)
- [109] arXiv:1911.01379 (replaced) [pdf, other]
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Title: Constraining short gamma-ray burst jet properties with gravitational waves and gamma raysComments: Matches published versionJournal-ref: ApJ 893 38 (2020)Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc)
- [110] arXiv:1911.04424 (replaced) [pdf, other]
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Title: Black Hole Coagulation: Modeling Hierarchical Mergers in Black Hole PopulationsComments: 17 pages, 16 figures, general purpose hierarchical population code to be released for public use in the near futureSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [111] arXiv:1911.05364 (replaced) [pdf, other]
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Title: Multi-messenger signals from short gamma ray burstsComments: 12 pages; accepted to the Proceedings of Science; based on contributed talk at "Multifrequency Behaviour of High Energy Cosmic Sources - XIII", Palermo, 3-8 June 2019Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)
- [112] arXiv:1911.06826 (replaced) [pdf, other]
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Title: Chemodynamics of barred galaxies in cosmological simulations: On the Milky Way's quiescent merger history and in-situ bulgeAuthors: F. Fragkoudi, R. J. J. Grand, R. Pakmor, G. Blázquez-Calero, I. Gargiulo, F. Gomez, F. Marinacci, A. Monachesi, M. K. Ness, I. Perez, P. Tissera, S. D. M. WhiteComments: Accepted for publication in MNRAS; 19 pages, 17 figures + 6 pages of appendices; Updated figures 11 and 12 (show the relation between chemodynamics and formation history)Subjects: Astrophysics of Galaxies (astro-ph.GA)
- [113] arXiv:1911.09116 (replaced) [pdf, other]
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Title: Baryonic clues to the puzzling diversity of dwarf galaxy rotation curvesAuthors: Isabel M.E. Santos-Santos, Julio F. Navarro, Andrew Robertson, Alejandro Benítez-Llambay, Kyle A. Oman, Mark R. Lovell, Carlos S. Frenk, Aaron D. Ludlow, Azadeh Fattahi, Adam RitzComments: 20 pages, 16 figures, 1 table. Accepted for publication in MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA)
- [114] arXiv:1912.00110 (replaced) [pdf, other]
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Title: Detection of the 511 keV Galactic positron annihilation line with COSIAuthors: Carolyn A. Kierans, Steven E. Boggs, Andreas Zoglauer, Alex W. Lowell, Clio C. Sleator, Jacqueline Beechert, Terri J. Brandt, Pierre Jean, Hadar Lazar, Jarred M. Roberts, Thomas Siegert, John A. Tomsick, Peter von BallmoosComments: 14 pages, 12 figures. Submitted to ApJSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
- [115] arXiv:1912.01012 (replaced) [pdf, ps, other]
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Title: Non-steady heating of cool cores of galaxy clusters by ubiquitous turbulence and AGNComments: Accepted for publication in MNRASSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Astrophysics of Galaxies (astro-ph.GA)
- [116] arXiv:1912.04872 (replaced) [pdf, other]
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Title: Amending the halo model to satisfy cosmological conservation lawsComments: Changes made to Figures 1-5, accepted in journal Physical Review DSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [117] arXiv:1912.09778 (replaced) [pdf, other]
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Title: From the bulge to the outer disc: StarHorse stellar parameters, distances, and extinctions for stars in APOGEE DR16 and other spectroscopic surveysAuthors: A. B. A. Queiroz, F. Anders, C. Chiappini, A. Khalatyan, B. X. Santiago, M. Steinmetz, M. Valentini, A. Miglio, D. Bossini, B. Barbuy, I. Minchev, D. Minniti, D. A. García Hernández, M. Schultheis, R. L. Beaton, T. C. Beers, D. Bizyaev, J. R. Brownstein, K. Cunha, J. G. Fernández-Trincado, P. M. Frinchaboy, R. R. Lane, S. R. Majewski, D. Nataf, C. Nitschelm, K. Pan, A. Roman-Lopes, J. S. Sobeck, G. Stringfellow, O. ZamoraComments: Accepted to A&A. 17 pages, 11 figures. Data products are available at this https URL, (doi:10.17876/data/2020_2)Subjects: Astrophysics of Galaxies (astro-ph.GA)
- [118] arXiv:1912.12218 (replaced) [pdf, other]
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Title: Thunder and Lightning: Using Neutron-Star Mergers as Simultaneous Standard Candles and Sirens to Measure Cosmological ParametersAuthors: Zoheyr DoctorComments: 10 pages, 2 figuresJournal-ref: ApJL 892 L16 (2020)Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [119] arXiv:2001.00638 (replaced) [pdf, other]
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Title: Nonsingular Ekpyrotic Cosmology with a Nearly Scale-Invariant Spectrum of Cosmological Perturbations and Gravitational WavesComments: 9 pages, a few typos corrected, matches published versionJournal-ref: Phys. Rev. D 101, 063522 (2020)Subjects: High Energy Physics - Theory (hep-th); Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Phenomenology (hep-ph)
- [120] arXiv:2001.01160 (replaced) [pdf, other]
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Title: The splashback radius of optically selected clusters with Subaru HSC Second Public Data ReleaseAuthors: Ryoma Murata, Tomomi Sunayama, Masamune Oguri, Surhud More, Atsushi J. Nishizawa, Takahiro Nishimichi, Ken OsatoComments: 32 pages, 13 figures, 6 tables. v2 matches accepted version that will be published in PASJ (minor changes from v1); abstract abridged to meet arXiv requirementsSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [121] arXiv:2001.02486 (replaced) [pdf, other]
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Title: Evidence for Galactic disc RR~Lyrae stars in the Solar neighbourhoodComments: 12 pages, 9 figures, Accepted for publication in MNRAS, final versionSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)
- [122] arXiv:2001.07552 (replaced) [pdf, other]
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Title: Exact solutions of domain wall junctions in arbitrary dimensionsComments: 34 pages, 10 figures; Several comments and new reference were addedSubjects: High Energy Physics - Theory (hep-th); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Phenomenology (hep-ph)
- [123] arXiv:2001.08266 (replaced) [pdf, other]
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Title: Searching for central stars of planetary nebulae in Gaia DR2Comments: 15 pages, 11 figures, accepted for publication in Astronomy & AstrophysicsSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
- [124] arXiv:2001.09728 (replaced) [pdf, ps, other]
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Title: Bounds on Lorentz invariance violation from MAGIC observation of GRB 190114CAuthors: MAGIC Collaboration: V. A. Acciari (1), S. Ansoldi (2,3), L. A. Antonelli (4), A. Arbet Engels (5), D. Baack (6), A. Babić (7), B. Banerjee (8), U. Barres de Almeida (9), J. A. Barrio (10), J. Becerra González (1), W. Bednarek (11), L. Bellizzi (12), E. Bernardini (13,14), A. Berti (15), J. Besenrieder (16), W. Bhattacharyya (13), C. Bigongiari (4), A. Biland (5), O. Blanch (17), G. Bonnoli (12), Ž. Bošnjak (7), G. Busetto (14), R. Carosi (18), G. Ceribella (16), M. Cerruti (19), Y. Chai (16), A. Chilingarian (20), S. Cikota (7), S. M. Colak (17), U. Colin (16), E. Colombo (1), J. L. Contreras (10), J. Cortina (21), S. Covino (4), G. D'Amico (16), V. D'Elia (4), P. Da Vela (18,22), F. Dazzi (4), A. De Angelis (14), B. De Lotto (2), M. Delfino (17,23), J. Delgado (17,23), et al. (141 additional authors not shown)Comments: 8 pages, 5 figuresSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
- [125] arXiv:2001.11470 (replaced) [pdf, other]
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Title: Distinguishing high-mass binary neutron stars from binary black holes with second- and third-generation gravitational wave observatoriesComments: 18 pages, 6 figures. Accepted manuscriptSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); General Relativity and Quantum Cosmology (gr-qc)
- [126] arXiv:2001.11893 (replaced) [pdf, ps, other]
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Title: Expression of the Holtsmark function in terms of hypergeometric $_2F_2$ and Airy $\mathrm{Bi}$ functionsAuthors: Jean-Christophe PainSubjects: Mathematical Physics (math-ph); Astrophysics of Galaxies (astro-ph.GA); Atomic Physics (physics.atom-ph)
- [127] arXiv:2002.00687 (replaced) [pdf, other]
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Title: A Toy Model for the Electromagnetic Output of Neutron-star Merger Prompt Collapse to a Black Hole: Magnetized Neutron-star CollisionsAuthors: Antonios NathanailComments: 14 pages, 10 figures, ApJ acceptedJournal-ref: The Astrophysical Journal, Volume 892, Issue 1, id.35 (2020)Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc)
- [128] arXiv:2002.06980 (replaced) [pdf, other]
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Title: ProSpect: Generating Spectral Energy Distributions with Complex Star Formation and Metallicity HistoriesAuthors: A.S.G. Robotham, S. Bellstedt, C. del P. Lagos, J.E. Thorne, L.J. Davies, S.P. Driver, M. BravoComments: Accepted for publication in MNRAS. New version: 28 pages, 38 figures, 8 tablesSubjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO); Instrumentation and Methods for Astrophysics (astro-ph.IM)
- [129] arXiv:2002.09829 (replaced) [pdf, ps, other]
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Title: A Small-Scale Investigation of Molecular Emission toward the Tip of the Western Lobe of W50/SS433Comments: 15 pages, 12 figures, 3 tables. Published to the Astrophysical JournalSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Astrophysics of Galaxies (astro-ph.GA)
- [130] arXiv:2002.10189 (replaced) [pdf, ps, other]
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Title: Reconstructing the Fraction of Baryons in the Intergalactic Medium with Fast Radio Bursts via Gaussian ProcessesComments: 14 pages, 6 figures, revtex4; v2: discussions added, JCAP in press; v3: published versionJournal-ref: JCAP 2004 (2020) 023Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc)
- [131] arXiv:2003.03625 (replaced) [pdf, ps, other]
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Title: Simulating the Fermi Bubbles as Forward Shocks Driven by AGN JetsComments: Slightly revised version, accepted for publication in ApJ. 15 pages, 15 figuresSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Astrophysics of Galaxies (astro-ph.GA)
- [132] arXiv:2003.04568 (replaced) [pdf, ps, other]
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Title: Lower surface gravitational redshift induced by higher curvature effectsComments: 30 pages, 16 figuresSubjects: General Relativity and Quantum Cosmology (gr-qc); Instrumentation and Methods for Astrophysics (astro-ph.IM); High Energy Physics - Theory (hep-th)
- [133] arXiv:2003.08832 (replaced) [pdf, other]
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Title: Galaxy rotation curves from external influence on Schwarzschild geometryAuthors: A. BhattacharyayComments: 7 pages and 1 figure. The present version includes derivation of the Baryonic Tully-Fisher relation with correct order of magnitude of the amplitude based on the modified metric. Trajectories of particles of conserved energy in the absence of asymptotic flatness are also discussed in this versionSubjects: General Relativity and Quantum Cosmology (gr-qc); Astrophysics of Galaxies (astro-ph.GA)
- [134] arXiv:2003.08998 (replaced) [pdf, other]
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Title: Evolutionary Models for 43 Galactic Supernova Remnants with Distances and X-ray SpectraComments: 57 pages, 7 figuresSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Astrophysics of Galaxies (astro-ph.GA)
- [135] arXiv:2003.10753 (replaced) [pdf, other]
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Title: Nebulosities of the Symbiotic Binary R Aquarii -- A Short ReviewComments: Conference proceeding, accepted for publication in PoS-SISSASubjects: Solar and Stellar Astrophysics (astro-ph.SR); High Energy Astrophysical Phenomena (astro-ph.HE)
- [136] arXiv:2004.01199 (replaced) [pdf, other]
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Title: Vacuum arbitrariness and the Hubble tensionAuthors: Ali KayaComments: 18 pages, 2 figures, v2: references addedJournal-ref: Phys. Rev. D 101, 083523, 2020Subjects: High Energy Physics - Theory (hep-th); Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Phenomenology (hep-ph)
- [137] arXiv:2004.02733 (replaced) [pdf, other]
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Title: Searching for solar axions at the Sudbury Neutrino ObservatoryComments: v2: citation and one point of clarification added. 5 pages, 1 figureSubjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [138] arXiv:2004.03306 (replaced) [pdf, ps, other]
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Title: Very high energy $γ$-ray emission from two blazars of unknown redshift and upper limits on their distanceAuthors: H.E.S.S. Collaboration, H. Abdalla, R. Adam, F. Aharonian, F. Ait Benkhali, E.O. Angüner, M. Arakawa, C. Arcaro, C. Armand, T. Armstrong, H. Ashkar, M. Backes, V. Baghmanyan, V. Barbosa Martins, A. Barnacka, M. Barnard, Y. Becherini, D. Berge, K. Bernlöhr, M. Böttcher, C. Boisson, J. Bolmont, S. Bonnefoy, J. Bregeon, M. Breuhaus, F. Brun, P. Brun, M. Bryan, M. Büchele, T. Bulik, T. Bylund, S. Caroff, A. Carosi, S. Casanova, T. Chand, S. Chandra, A. Chen, G. Cotter, M. Curyło, I.D. Davids, J. Davies, C. Deil, J. Devin, P. deWilt, L. Dirson, A. Djannati-Ataï, A. Dmytriiev, A. Donath, V. Doroshenko, J. Dyks, K. Egberts, F. Eichhorn, G. Emery, J.-P. Ernenwein, K. Feijen, S. Fegan, A. Fiasson, G. Fontaine, S. Funk, M. Füßling, S. Gabici, Y.A. Gallant, G. Giavitto, et al. (166 additional authors not shown)Comments: Accepted for publication in MNRAS. 13 pages, 4 figuresSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
- [139] arXiv:2004.03986 (replaced) [pdf, other]
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Title: Spectral signatures of H-rich material stripped from a non-degenerate companion by a Type Ia supernovaAuthors: Luc Dessart (IAP, Paris), Douglas C. Leonard (San Diego State University), Jose L. Prieto (Universidad Diego Portales, Chile)Comments: Accepted for publication in A&A, references added in proofsSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)
- [140] arXiv:2004.04749 (replaced) [pdf, other]
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Title: Multi-phase outflows in post starburst E+A galaxies -- II. A direct connection between the neutral and ionized outflow phasesComments: MNRAS acceptedSubjects: Astrophysics of Galaxies (astro-ph.GA)
- [141] arXiv:2004.06214 (replaced) [pdf, other]
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Title: Holographic dark energy with non-minimal derivative coupling to gravity effectsAuthors: Chonticha Kritpetch (IF Naresuan), Candrasyah Muhammad (IF Naresuan), Burin Gumjudpai (IF Naresuan and ThEP Center)Comments: 11 pages, 12 figuresSubjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [142] arXiv:2004.06437 (replaced) [pdf, other]
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Title: Ekpyrotic Cosmology with a Zero-Shear S-BraneComments: 8 pages, no figures, minor error in the initial version correctedSubjects: High Energy Physics - Theory (hep-th); Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Phenomenology (hep-ph)
- [143] arXiv:2004.06681 (replaced) [pdf, other]
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Title: A cryogenic ice setup to simulate carbon atom reactions in interstellar icesAuthors: D. Qasim, M.J.A. Witlox, G. Fedoseev, K.-J. Chuang, T. Banu, S.A. Krasnokutski, S. Ioppolo, J. Kastner, E.F. van Dishoeck, H. LinnartzComments: Accepted for publication in Review of Scientific InstrumentsSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)
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