Astrophysics
New submissions
[ showing up to 2000 entries per page: fewer | more ]
New submissions for Mon, 20 Apr 20
- [1] arXiv:2004.07819 [pdf, other]
-
Title: Quantifying Excess Power from Radio Frequency Interference in Epoch of Reionization MeasurementsSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)
We quantify the effect of radio frequency interference (RFI) on Epoch of Reionization (EoR) power spectra. Specifically, we investigate how the frequency structure of source emission generates contamination in higher-order wave modes that is much more problematic than smooth-spectrum foreground sources. We find that even a single relatively dim RFI source can overwhelm typical estimates of the EoR power spectrum signal on cosmological modes of interest. If total apparent RFI flux density in an integration is kept below 1 mJy, an EoR detection should be feasible given no other systematic. These results emphasize the need for highly effective RFI mitigation strategies for telescopes used to search for the EoR.
- [2] arXiv:2004.07834 [pdf]
-
Title: CAB: Towards the RNA-world in the interstellar medium -- detection of urea, and search of 2-amino-oxazole and simple sugarsAuthors: Izaskun Jimenez-Serra (1), Jesus Martin-Pintado (1), Victor M. Rivilla (2), Lucas F. Rodriguez Almeida (1), Elena R. Alonso Alonso (3,4), Shaoshan Zeng (5), Emilio J. Cocinero (3,4), Sergio Martin (6,7), Miguel Requena-Torres (8), Rafa Martin-Domenech (9), Leonardo Testi (10,2) ((1) Centro de Astrobiologia (CSIC-INTA), Spain (2) INAF-Osservatorio Astrofisico di Arcetri, Italy (3) Universidad del Pais Vasco (UPV-EHU), Spain (4) Biofisika Institute (CSIC, UPV/EHU), Spain (5) Queen Mary University of London, UK (6) European Southern Observatory, Chile (7) Joint ALMA Observatory, Chile (8) University of Maryland, USA (9) Harvard-Smithsonian Center for Astrophysics, USA (10) European Southern Observatory, Germany)Comments: 61 pages, 4 figures, 6 tables, accepted for AstrobiologySubjects: Astrophysics of Galaxies (astro-ph.GA); Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
In the past decade, Astrochemistry has witnessed an impressive increase in the number of detections of complex organic molecules. Some of these species are of prebiotic interest such as glycolaldehyde, the simplest sugar, or amino acetonitrile, a possible precursor of glycine. Recently, we have reported the detection of two new nitrogen-bearing complex organics, glycolonitrile and Z-cyanomethanimine, known to be intermediate species in the formation process of ribonucleotides within theories of a primordial ribonucleic acid (RNA)-world for the origin of life. In this paper, we present deep and high-sensitivity observations toward two of the most chemically rich sources in the Galaxy: a Giant Molecular Cloud in the center of the Milky Way (G+0.693-0.027) and a proto-Sun (IRAS16293-2422 B). Our aim is to explore whether the key precursors considered to drive the primordial RNA-world chemistry, are also found in space. Our high-sensitivity observations reveal that urea is present in G+0.693-0.027 with an abundance of about 5x10-11. This is the first detection of this prebiotic species outside a star-forming region. Urea remains undetected toward the proto-Sun IRAS16293-2422 B (upper limit to its abundance of less than 2x10-11). Other precursors of the RNA-world chemical scheme such as glycolaldehyde or cyanamide are abundant in space, but key prebiotic species such as 2- amino-oxazole, glyceraldehyde or dihydroxyacetone are not detected in either source. Future more sensitive observations targeting the brightest transitions of these species will be needed to disentangle whether these large prebiotic organics are certainly present in space.
- [3] arXiv:2004.07846 [pdf, other]
-
Title: The Angular Momentum of the Circumgalactic Medium in the TNG100 SimulationAuthors: Daniel DeFelippis, Shy Genel, Greg L. Bryan, Dylan Nelson, Annalisa Pillepich, Lars HernquistComments: Accepted to ApJ. 16 pages, 12 figuresSubjects: Astrophysics of Galaxies (astro-ph.GA)
We present an analysis of the angular momentum content of the circumgalactic medium (CGM) using TNG100, one of the flagship runs of the IllustrisTNG project. We focus on Milky Way-mass halos ($\sim 10^{12} \; M_{\odot}$) at $z=0$ but also analyze other masses and redshifts up to $z=5$. We find that the CGM angular momentum properties are strongly correlated with the stellar angular momentum of the corresponding galaxy: the CGM surrounding high-angular momentum galaxies has systematically higher angular momentum and is better aligned to the rotational axis of the galaxy itself than the CGM surrounding low-angular momentum galaxies. Both the hot and cold phases of the CGM show this dichotomy, though it is stronger for colder gas. The CGM of high-angular momentum galaxies is characterized by a large wedge of cold gas with rotational velocities at least $\sim1/2$ of the halo's virial velocity extending out to $\sim 1/2$ of the virial radius, and by biconical polar regions dominated by radial velocities suggestive of galactic fountains; both of these features are absent from the CGM of low-angular momentum galaxies. These conclusions are general to halo masses $\lesssim 10^{12} \; M_{\odot}$ and for $z \lesssim 2$, but do not apply for more massive halos or at the highest redshift studied. By comparing simulations run with alterations to the fiducial feedback model, we identify the better alignment of the CGM to high-angular momentum galaxies as a feedback-independent effect and the galactic winds as a dominant influence on the CGM's angular momentum.
- [4] arXiv:2004.07847 [pdf, other]
-
Title: The Stellar Mass Fundamental Plane: The virial relation and a very thin plane for slow-rotatorsComments: 13 pages, 9 figures, 3 tables, accepted for publication in MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
Early-type galaxies -- slow and fast rotating ellipticals (E-SRs and E-FRs) and S0s/lenticulars -- define a Fundamental Plane (FP) in the space of half-light radius $R_e$, enclosed surface brightness $I_e$ and velocity dispersion $\sigma_e$. Since $I_e$ and $\sigma_e$ are distance-independent measurements, the thickness of the FP is often expressed in terms of the accuracy with which $I_e$ and $\sigma_e$ can be used to estimate sizes $R_e$. We show that: 1) The thickness of the FP depends strongly on morphology. If the sample only includes E-SRs, then the observed scatter in $R_e$ is $\sim 16\%$, of which only $\sim 9\%$ is intrinsic. Removing galaxies with $M_*<10^{11}M_\odot$ further reduces the observed scatter to $\sim 13\%$ ($\sim 4\%$ intrinsic). The observed scatter increases to the $\sim 25\%$ usually quoted in the literature if E-FRs and S0s are added. If the FP is defined using the eigenvectors of the covariance matrix of the observables, then the E-SRs again define an exceptionally thin FP, with intrinsic scatter of only $5\%$ orthogonal to the plane. 2) The structure within the FP is most easily understood as arising from the fact that $I_e$ and $\sigma_e$ are nearly independent, whereas the $R_e-I_e$ and $R_e-\sigma_e$ correlations are nearly equal and opposite. 3) If the coefficients of the FP differ from those associated with the virial theorem the plane is said to be `tilted'. If we multiply $I_e$ by the global stellar mass-to-light ratio $M_*/L$ and we account for non-homology across the population by using S\'ersic photometry, then the resulting stellar mass FP is less tilted. Accounting self-consistently for $M_*/L$ gradients will change the tilt. The tilt we currently see suggests that the efficiency of turning baryons into stars increases and/or the dark matter fraction decreases as stellar surface brightness increases.
- [5] arXiv:2004.07848 [pdf, other]
-
Title: The evolution of stellar triples: The most common evolutionary pathwaysComments: 18 pages, 16 figures, 2 tables, submitted to A&ASubjects: Solar and Stellar Astrophysics (astro-ph.SR); Earth and Planetary Astrophysics (astro-ph.EP)
Many stars do not live alone, but instead have one or more stellar companions. Observations show that these binaries, triples and higher-order multiples are common. Whereas the evolution of single stars and binaries have been studied extensively, the same is not true for the evolution of stellar triples. To fill this gap in our general understanding of stellar lives, we aim to systematically explore the long-term evolution of triples and to map out the most common evolutionary pathways that triples go through. We quantitatively study how triples evolve, which processes are most relevant, and how this differs from binary evolution. We simulate the evolution of several large populations of triples with a population synthesis approach. We make use of the triple evolution code TRES to simulate the evolution of each triple in a consistent way; including three-body dynamics (based on the secular approach), stellar evolution and their mutual influences. We simulate the evolution of the system up until mass transfer starts, the system becomes dynamically unstable, or a Hubble time has passed. We find that stellar interactions are common in triples. Compared to a binary population, we find that the fraction of systems that can undergo mass transfer is about 2 to 3 times larger in triples. Moreover, whereas in binaries the orbits typically reach circularisation before Roche-lobe overflow, this is not true anymore in triples. In our simulations, about 40% of systems retain an eccentric orbit. Additionally, we discuss various channels of triple evolution in detail such as those where the secondary or the tertiary is the first star to initiate a mass transfer event.
- [6] arXiv:2004.07854 [pdf, other]
-
Title: SCORCH. III. Analytical Models of Reionization with Varying Clumping FactorsComments: 13 pages, 6 figures. Comments are welcomeSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
In the Simulations and Constructions of the Reionization of Cosmic Hydrogen (SCORCH) project, we compare analytical models of the hydrogen ionization fraction with radiation-hydrodynamic simulations. We derive analytical models of the mass-weighted hydrogen ionization fraction from the local ionization balance equations as a more accurate alternative to the widely adopted model based on the volume filling factor. In particular, our model has a recombination term quadratic in the ionization fraction, which is consistent with the two-body interaction nature of recombination. Then, we use the radiation-hydrodynamic simulations to study the clumping factors needed to solve the analytical equations, and provide accurate fitting functions. We find that the ionized hydrogen clumping factors from our radiative transfer simulations are significantly different than those from other simulations that use a uniform photoionization background. In addition to redshift dependence, we also see the dependence of ionized hydrogen clumping factor on ionization fraction, and we incorporate this into our fits. We calculate the reionization histories using our analytical models and clumping factors and compare with widely adopted models, and all of our models achieve $<7\%$ difference from simulation results while the other models have $>20\%$ deviations. The Thomson optical depths from reionization calculated from our analytical models result in $<5\%$ deviation from simulations, while the previous analytical models have $>20\%$ difference in and could result in biased conclusions of the IGM reionization.
- [7] arXiv:2004.07855 [pdf, other]
-
Title: Spherical Bayesian mass-mapping with uncertainties: full sky observations on the celestial sphereSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
To date weak gravitational lensing surveys have typically been restricted to small fields of view, such that the $\textit{flat-sky approximation}$ has been sufficiently satisfied. However, with Stage IV surveys ($\textit{e.g. LSST}$ and $\textit{Euclid}$) imminent, extending mass-mapping techniques to the sphere is a fundamental necessity. As such, we extend the sparse hierarchical Bayesian mass-mapping formalism presented in previous work to the spherical sky. For the first time, this allows us to construct $\textit{maximum a posteriori}$ spherical weak lensing dark-matter mass-maps, with principled Bayesian uncertainties, without imposing or assuming Gaussianty. We solve the spherical mass-mapping inverse problem in the analysis setting adopting a sparsity promoting Laplace-type wavelet prior, though this theoretical framework supports all log-concave posteriors. Our spherical mass-mapping formalism facilitates principled statistical interpretation of reconstructions. We apply our framework to convergence reconstruction on high resolution N-body simulations with pseudo-Euclid masking, polluted with a variety of realistic noise levels, and show a dramatic increase in reconstruction fidelity compared to standard approaches. Furthermore we perform the largest joint reconstruction to date of all publically available shear observational datasets (combining DESY1, KiDS450 and CFHTLens) and find that our formalism recovers a convergence map with significantly enhanced small-scale detail. Within our Bayesian framework we validate, in a statistically rigourous manner, the community's intuition regarding the need to smooth spherical Kaiser-Squies estimates to provide physically meaningful convergence maps. Such approaches cannot reveal the small-scale physical structures that we recover within our framework.
- [8] arXiv:2004.07865 [pdf, other]
-
Title: PRASSE -- The Pulsar Automated Search Script EnsembleComments: 8 pages, 10 figuresSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); High Energy Astrophysical Phenomena (astro-ph.HE)
The search for pulsars produces a massive amount of data which needs to be processed and analyzed. The limited speed of manual observation necessitates the involvement of large numbers of people to keep up with data collection. This paper turns to the automated alternative by examining the methodology of an algorithm built to automatically filter through processed and reduced data, which then presents the most promising data to human observers for confirmation and more complex analysis. The benefits and shortcomings of this algorithm are examined while explaining plans for future testing.
- [9] arXiv:2004.07866 [pdf, other]
-
Title: The XXL Survey XLIV. Sunyaev-Zel'dovich mapping of a low-mass cluster at z~1: a multi-wavelength approachAuthors: M. Ricci, R. Adam, D. Eckert, P. Ade, P. André, A. Andrianasolo, B. Altieri, H. Aussel, A. Beelen, C. Benoist, A. Benoît, S. Berta, A. Bideaud, M. Birkinshaw, O. Bourrion, D. Boutigny, M. Bremer, M. Calvo, A. Cappi, L. Chiappetti, A. Catalano, M. De Petris, F.-X. Désert, S. Doyle, E. F. C. Driessen, L. Faccioli, C. Ferrari, S. Fotopoulou, F. Gastaldello, P. Giles, A. Gomez, J. Goupy, O. Hahn, C. Horellou, F. Kéruzoré, E. Koulouridis, C. Kramer, B. Ladjelate, G. Lagache, S. Leclercq, J.-F. Lestrade, J.F. Macías-Pérez, A. Mantz, B. Maughan, S. Maurogordato, P. Mauskopf, A. Monfardini, F. Pacaud, L. Perotto, M. Pierre, G. Pisano, E. Pompei, N. Ponthieu, V. Revéret, A. Ritacco, C. Romero, H. Roussel, F. Ruppin, M. Sánchez Portal, K. Schuster, M. Sereno, et al. (4 additional authors not shown)Comments: Accepted in A&ASubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
In this paper, we present resolved observations of the Sunyaev-Zel'dovich (SZ) effect, obtained with the NIKA2 camera, towards the cluster of galaxies XLSSC102, a relatively low-mass system ($M_{500} \sim 2 \times 10^{14}$ M$_{\odot}$) at $z = 0.97$ detected from the XXL survey. We combine NIKA2 SZ data, XMM-Newton X-ray data, and Megacam optical data to explore, respectively, the spatial distribution of the gas electron pressure, the gas density, and the galaxies themselves. We find significant offsets between the X-ray peak, the SZ peak, the brightest cluster galaxy, and the peak of galaxy density. Additionally, the galaxy distribution and the gas present elongated morphologies. This is interpreted as the sign of a recent major merging event, which induced a local boost of the gas pressure towards the north of XLSSC102 and stripped the gas out of the galaxy group. The NIKA2 data are also combined with XXL data to construct the thermodynamic profiles of XLSSC102, obtaining relatively tight constraints up to about $\sim r_{500}$, and revealing properties that are typical of disturbed systems. We also explore the impact of the cluster centre definition and the implication of local pressure substructure on the recovered profiles. Finally, we derive the global properties of XLSSC102 and compare them to those of high-mass-and-low-redshift systems, finding no strong evidence for non-standard evolution. We also use scaling relations to obtain alternative mass estimates from our profiles. The variation between these different mass estimates reflects the difficulty to accurately measure the mass of low-mass clusters at z$\sim$1, especially with low signal-to-noise ratio (S/N) data and for a disturbed system. However, it also highlights the strength of resolved SZ observations alone and in combination with survey-like X-ray data.
- [10] arXiv:2004.07885 [pdf, other]
-
Title: Photometric Redshifts with the LSST II: The Impact of Near-Infrared and Near-Ultraviolet PhotometryAuthors: Melissa L. Graham, Andrew J. Connolly, Winnie Wang, Samuel J. Schmidt, Christopher B. Morrison, Željko Ivezić, Sébastien Fabbro, Patrick Côté, Scott F. Daniel, R. Lynne Jones, Mario Jurić, Peter Yoachim, J. Bryce KalmbachComments: 21 pages, 16 figures, 4 tables, accepted to AJSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)
Accurate photometric redshift (photo-$z$) estimates are essential to the cosmological science goals of the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST). In this work we use simulated photometry for mock galaxy catalogs to explore how LSST photo-$z$ estimates can be improved by the addition of near-infrared (NIR) and/or ultraviolet (UV) photometry from the Euclid, WFIRST, and/or CASTOR space telescopes. Generally, we find that deeper optical photometry can reduce the standard deviation of the photo-$z$ estimates more than adding NIR or UV filters, but that additional filters are the only way to significantly lower the fraction of galaxies with catastrophically under- or over-estimated photo-$z$. For Euclid, we find that the addition of ${JH}$ $5{\sigma}$ photometric detections can reduce the standard deviation for galaxies with $z>1$ ($z>0.3$) by ${\sim}20\%$ (${\sim}10\%$), and the fraction of outliers by ${\sim}40\%$ (${\sim}25\%$). For WFIRST, we show how the addition of deep ${YJHK}$ photometry could reduce the standard deviation by ${\gtrsim}50\%$ at $z>1.5$ and drastically reduce the fraction of outliers to just ${\sim}2\%$ overall. For CASTOR, we find that the addition of its ${UV}$ and $u$-band photometry could reduce the standard deviation by ${\sim}30\%$ and the fraction of outliers by ${\sim}50\%$ for galaxies with $z<0.5$. We also evaluate the photo-$z$ results within sky areas that overlap with both the NIR and UV surveys, and when spectroscopic training sets built from the surveys' small-area deep fields are used.
- [11] arXiv:2004.07892 [pdf, other]
-
Title: Redshift Horizon for the Origins Space Telescope from Primordial Dust EmissionComments: 3 pages, 2 figures. Accepted for publication in BAAA, Vol. 61B, 2020. arXiv admin note: text overlap with arXiv:2001.02720Subjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
We explore the possibility of detecting the first galaxies with the next generation Origins Space Telescope (OST) by applying an analytical model of primordial dust emission. By analysing source densities as a function of redshift (z), and considering deep-field exposures with the Origins Survey Spectrometer, we estimate that the redshift horizon for detecting one individual source would be above z~7 for systems with dust-to-metal ratios higher than those expected for typical primeval galaxies. On the other hand, if confusion limits could be overcome, the Far-infrared Imager and Polarimeter would enable the detection of more typical fainter systems at z>7. Given the dependence of the obtained results with the properties of primeval dust, we conclude that the OST could provide important clues to the nature of the interestellar medium in the early Universe.
- [12] arXiv:2004.07901 [pdf, ps, other]
-
Title: Evidence for variability timescale dependent UV/X-ray delay in Seyfert 1 AGN NGC 7469Authors: Mayukh Pahari (Southampton, UK), Ian M. McHardy (Southampton, UK), Federico Vincentelli (Southampton, UK), Edward M. Cackett (Wayne State, USA), Bradley M. Peterson (Ohio state and STSI, USA), Michael R. Goad (Leicester, UK), Kayhan Gültekin (Michigan, USA), Keith Horne (St. Andrews, UK)Comments: 13 pages, 9 figures, 1 table, accepted for publication in MNRASSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Astrophysics of Galaxies (astro-ph.GA)
Using a month-long X-ray lightcurve from ${\it RXTE}$/PCA and 1.5 month long UV continuum lightcurves from ${\it IUE}$ spectra in 1220$-$1970 $\r{A}$, we performed a detailed time-lag study of the Seyfert 1 galaxy NGC 7469. Our cross-correlation analysis confirms previous results showing that the X-rays are delayed relative to the UV continuum at 1315 $\r{A}$ by 3.49 $\pm$ 0.22 days which is possibly caused by either propagating fluctuation or variable comptonisation. However, if variations slower than 5 days are removed from the X-ray lightcurve, the UV variations then lag behind the X-rays variations by 0.37$\pm$0.14 day, consistent with reprocessing of the X-rays by a surrounding accretion disc. A very similar reverberation delay is observed between ${\it Swift}$/XRT X-ray and ${\it Swift}$/UVOT UVW2, U lightcurves. Continuum lightcurves extracted from the ${\it Swift}$/GRISM spectra show delays with respect to X-rays consistent with reverberation. Separating the UV continuum variations faster and slower than 5 days, the slow variations at 1825 $\r{A}$ lag those at 1315 $\r{A}$ by $0.29\pm0.06$ day, while the fast variations are coincident ($0.04\pm0.12$ day). The UV/optical continuum reverberation lag from ${\it IUE}$, ${\it Swift}$ and other optical telescopes at different wavelengths are consistent with the relationship: $\tau \propto \lambda^{4/3}$, predicted for the standard accretion disc theory while the best-fit X-ray delay from ${\it RXTE}$ and ${\it Swift}$/XRT shows a negative X-ray offset of $\sim$0.38 days from the standard disc delay prediction.
- [13] arXiv:2004.07907 [pdf, other]
-
Title: Supermassive black holes as possible sources of ultra high energy cosmic raysComments: 14 pages, 6 figures, accepted to ApJSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc)
Production and acceleration mechanisms of ultra-high-energy cosmic rays (UHECRs) of energy $>10^{20}$eV, clearly beyond the GZK-cutoff limit remain unclear that points to exotic nature of the phenomena. Recent observations of extragalactic neutrino may indicate the source of UHECRs being an extragalactic supermassive black hole (SMBH). We demonstrate that ultra-efficient energy extraction from rotating SMBH driven by the magnetic Penrose process (MPP) could indeed foot the bill. We envision ionization of neutral particles, such as neutron beta-decay, skirting close to the black hole horizon that energizes protons to over $10^{20}$eV for SMBH of mass $10^9 M_{\odot}$ and magnetic field of strength $10^4$G. Applied to Galactic center SMBH we have proton energy of order $\approx 10^{15.6}$eV that coincides with the knee of the cosmic ray spectra. We show that large $\gamma_z$ factors of high-energy particles along the escaping directions occur only in the presence of induced charge of the black hole that is known as the Wald charge in the case of uniform magnetic field. It is remarkable that the process neither requires extended acceleration zone, nor fine-tuning of accreting matter parameters. Further, this leads to certain verifiable constraints on SMBH's mass and magnetic field strength as UHECRs sources. This clearly makes ultra-efficient regime of MPP one of the most promising mechanisms for fueling UHECRs powerhouse.
- [14] arXiv:2004.07908 [pdf, ps, other]
-
Title: The hydrogen Balmer lines and jump in absorption in accretion disc modeling -- an ultraviolet-optical spectral analysis of the dwarf novae UZ Serpentis and CY LyraeComments: 19 pages, 13 figures, submitted to MNRASSubjects: Solar and Stellar Astrophysics (astro-ph.SR); High Energy Astrophysical Phenomena (astro-ph.HE)
The spectra of disc-dominated cataclysmic variables (CVs) often deviate from the spectra of accretion disc models; in particular, the Balmer jump and absorption lines are found to be shallower in the observations than in the models. We carried out a combined ultraviolet-optical spectral analysis of two dwarf novae: UZ Ser in outburst, decline, and quiescence, and CY Lyr on the rise to outburst and in outburst. We fit the Balmer jump and absorption lines, the continuum flux level and slope by adjusting the accretion rate, inclination, and disc outer radius. For both systems we find an accretion rate $\dot{M} \approx 8 \times 10^{-9}M_\odot$/yr in outburst, and $\dot{M} \approx 2-3 \times 10^{-9}M_\odot$/yr for the rise and decline phases. The outer disc radius we derive is smaller than expected ($R_{\rm disc} \approx 0.2a$, where $a$ is the binary separation), except during late rise (for CY Lyr) where $R_{\rm disc}=0.3a$. UZ Ser also reveals a 60,000~K white dwarf. These results show that during a dwarf nova cycle the radius of the disc is the largest just before the peak of the outburst, in qualitative agreement with the disc instability model for dwarf nova outbursts. We suspect that an additional emitting component (e.g. disc wind) is also at work to reduce the slope of the continuum and size of the Balmer jump and absorption lines. We stress that both the outer disc radius and disc wind need to be taken into account for more realistic disc modeling of CVs.
- [15] arXiv:2004.07909 [pdf, ps, other]
-
Title: Broken SU(6) symmetry and massive hybrid starsComments: 12 pages, 7 figures. arXiv admin note: substantial text overlap with arXiv:1909.05400Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
In this work we revisit the quantum hadrodynamics (QHD) formalism to investigate hyperonic and hybrid stars with hyperon-meson couplings fixed via broken SU(6) group, in favor of a more general flavor group SU(3). This allows us to restrict a large number of free parameters to only one - the $\alpha_v$ - for the vector mesons, while the scalar meson can be constrained by the hyperon potential depth. We also employ an additional channel, the strangeness-hidden $\phi$ meson, which couples only to the hyperons and has a crucial role in the description of massive neutron stars. In hybrid stars, the quark phase is built with the SU(3) NJL model also with an additional vector channel in the Lagrangian, which enters as a free parameter within the limit imposed by the lattice QCD. We are able to reproduce 2.21 $M_\odot$ hyperonic star and 2.10 $M_\odot$ hybrid star. Both results are in agreement with the recently detected hyper massive pulsar MSP J0740+6620. With the models used in the present work, the minimum and the maximum masses of a hybrid star are very close to each other, indicating that if they exist, they are probably very rare in the universe.
- [16] arXiv:2004.07913 [pdf, other]
-
Title: Optical validation and characterisation of Planck PSZ1 sources at the Canary Islands observatories. II. Second year of ITP13 observationsAuthors: R. Barrena, A. Ferragamo, J. A. Rubiño-Martín, A. Streblyanska, A. Aguado-Barahona, D. Tramonte, R. T. Génova-Santos, A. Hempel, H. Lietzen, N. Aghanim, H. Böhringer, G. Chon, H. Dahle, M. Douspis, A. N. Lasenby, P. Mazzotta, J. B. Melin, E. Pointecouteau, G. W. Pratt, M. RossettiComments: Accepted for publications in A&A. 15 pages including 14 figures and 1 long tableSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
We report new galaxy clusters previously unknown included in the PSZ1 catalogue. The results here presented have been achieved during the second year of a 2-year observational programme, the ITP13, developed at the Roque de los Muchachos Observatory (La Palma, Spain). We characterise 75 SZ sources with low SZ significance, SZ S/N$<5.32$ by performing deep optical imaging and spectroscopy in order to associate actual galaxy clusters to the SZ Planck source. We adopt robust criteria, based on the 2D-spatial distribution, richness and velocity dispersions to confirm actual optical counterparts up to $z<0.85$. At the end of the ITP13 observational programme, we study 256 SZ sources with $Dec \geq -15^{\circ}$ (212 of them completely unknown), finding optical counterparts for 152 SZ sources. The ITP13 validation programme has allowed us to update the PSZ1 purity, which is now more refined, increasing from 72\% to 83\% in the low SZ S/N regime. Our results are consistent with the predicted purity curve for the full PSZ1 catalogue and with the expected fraction of false detections caused by the non-Gaussian noise of foreground signals. Indeed, we find a strong correlation between the number of unconfirmed sources and the thermal emission of diffuse galactic dust at 857 GHz, thus increasing the fraction of false Planck SZ detections at low galactic latitudes.
- [17] arXiv:2004.07914 [pdf, other]
-
Title: High-resolution VLA Imaging of Obscured Quasars: Young Radio Jets Caught in a Dense ISMAuthors: Pallavi Patil, Kristina Nyland, Mark Whittle, Carol Lonsdale, Mark Lacy, Colin Lonsdale, Dipanjan Mukherjee, A. C. Trapp, Amy E. Kimball, Lauranne Lanz, Belinda J. Wilkes, Andrew Blain, Jeremy J. Harwood, Andreas Efstathiou, Catherine VlahakisComments: Accepted for publication in ApJ, 38 pages, 14 figures, 6 tablesSubjects: Astrophysics of Galaxies (astro-ph.GA)
We present new sub-arcsecond-resolution Karl G. Jansky Very Large Array (VLA) imaging at 10 GHz of 155 ultra-luminous ($L_{\rm bol}\sim10^{11.7-14.2} L_\odot$) and heavily obscured quasars with redshifts $z \sim0.4-3$. The sample was selected to have extremely red mid-infrared (MIR)-optical color ratios based on data from Wide-Field Infrared Survey Explorer (WISE) along with a detection of bright, unresolved radio emission from the NRAO VLA Sky Survey (NVSS) or Faint Images of the Radio Sky at Twenty-Centimeters (FIRST) Survey. Our high-resolution VLA observations have revealed that the majority of the sources in our sample (93 out of 155) are compact on angular scales $<0.2^{\prime \prime}$ ($\leq 1.7$ kpc at $z \sim2$). The radio luminosities, linear extents, and lobe pressures of our sources are similar to young radio active galactic nuclei (AGN; e.g., Gigahertz Peaked Spectrum, GPS, and Compact Steep Spectrum, CSS, sources), but their space density is considerably lower. Application of a simple adiabatic lobe expansion model suggests relatively young dynamical ages ($\sim10^{4-7}$ years), relatively high ambient ISM densities ($\sim1-10^4$ cm$^{-3}$), and modest lobe expansion speeds ($\sim30-10,000$ km s$^{-1}$). Thus, we find our sources to be consistent with a population of newly triggered, young jets caught in a unique evolutionary stage in which they still reside within the dense gas reservoirs of their hosts. Based on their radio luminosity function and dynamical ages, we estimate only $\sim20\%$ of classical large scale FRI/II radio galaxies could have evolved directly from these objects. We speculate that the WISE-NVSS sources might first become GPS or CSS sources, of which some might ultimately evolve into larger radio galaxies.
- [18] arXiv:2004.07916 [pdf, other]
-
Title: The relativistic galaxy number counts in the weak field approximationComments: 16 pagesSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc)
We present a novel approach to compute systematically the relativistic projection effects at any order in perturbation theory within the weak field approximation. In this derivation the galaxy number counts is written completely in terms of the redshift perturbation. The relativistic effects break the symmetry along the line-of-sight and they source, contrarily to the standard perturbation theory, the odd multipoles of the matter power spectrum or 2-point correlation function, providing a unique signature for their detection in Large Scale Structure surveys. We show that our approach agrees with previous derivations (up to third order) of relativistic effects and, for the first time, we derive a model for the transverse Doppler effect. Moreover, we proof that in the Newtonian limit this approach is consistent with standard perturbation theory at any order.
- [19] arXiv:2004.07951 [pdf, other]
-
Title: Measuring Fluxes of Meteor Showers with the NASA All-Sky Fireball NetworkComments: 18 pages, 9 Figures, 2 Tables. Accepted in Planetary and Space Science, Meteoroids 2019 Conference Proceedings Special IssueSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM)
We present an algorithm developed to measure the fluxes of major meteor showers as observed in NASA's All-Sky Fireball Network cameras. Measurements of fluxes from the All-Sky cameras not only improve the Meteoroid Environment Office's (MEO's) ability to provide accurate risk assessments from major showers, but also allows the mass distribution of meteoroids within the shower to be constrained. This algorithm accounts for the shower-specific and event-specific exposure time and collecting area of the sky for nights where sufficiently large samples of shower meteors ($\sim 30$ or more from the shower) are observed. The fluxes derived from the All-Sky Fireball Network for the 2015 Geminid, 2016 Perseid and Quadrantid, 2017 Orionid, and 2018 Leonid shower peaks are calculated. All five of these shower fluxes show excellent agreement with expectations from independent measurements at different mass and luminosity limits. For four of these five showers, the measured mass indices are significantly shallower than what is currently assumed by the NASA Meteoroid Environment Office's (MEO's) annual meteor shower forecast. A direct comparison between forecasted and measured fluxes at limiting masses of $\sim 1 \thinspace \mathrm{g}$ shows good agreement for the three showers for which the observations took place near their peak activity.
- [20] arXiv:2004.07963 [pdf, other]
-
Title: A magnetic white-dwarf accretion model for the anomalous X-ray pulsar 4U 0142+61Comments: ApJ acceptedSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)
The quiescent emission of the anomalous X-ray pulsar (AXP) 4U 0142+61 extends over a broad range of energy, from radio up to hard X-rays. In particular, this object is unique among soft gamma-ray repeaters (SGRs) and AXPs in presenting simultaneously mid-infrared emission and pulsed optical emission. In spite of the many propositions to explain this wide range of emission, it still lacks one that reproduces all the observations. Filling this gap, we present a model to reproduce the quiescent spectral energy distribution of 4U 0142+61 from mid-infrared up to hard X-rays using plausible physical components and parameters. We propose that the persistent emission comes from a magnetic accreting white dwarf (WD) surrounded by a debris disk. This model assumes that: (i) the hard X-rays are due to the bremsstrahlung emission from the post-shock region of the accretion column; (ii) the soft X-rays are originated by hot spots on the WD surface; and (iii) the optical and infrared emissions are caused by an optically thick dusty disk, the WD photosphere, and the tail of the postshock region emission. In this scenario, the fitted model parameters indicate that 4U 0142+61 harbors a fast-rotator magnetic near-Chandrasekhar WD, which is very hot and hence young. Such a WD can be the recent outcome of a merger of two less massive WDs. In this case, 4U 0142+61 can evolve to an SN Ia and hence can give hints of the origin of these important astrophysical events. Additionally, we also present a new estimate of 4U 0142+61 distance, 3.78 (errors: +0.12 / -0.18 kpc), based on the measured Hydrogen column density and new interstellar extinction 3D maps.
- [21] arXiv:2004.07971 [pdf, other]
-
Title: Exoplanet System Kepler-2 with comparisons to Kepler-1 and 13Comments: Accepted by Astrophysics and Space ScienceSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
We have carried out an intensive study of photometric (Kepler Mission) and spectroscopic data on the system Kepler-2 (HAT-P-7A) using the dedicated software WinFitter. The mean individual data-point error of the normalized flux values for this system is 0.00015, leading to the model's specification for the mean reference flux to an accuracy of $\sim$0.5 ppm. This testifies to the remarkably high accuracy of the binned data-set, derived from over 1.8 million individual observations. Spectroscopic data are reported with the similarly high-accuracy radial velocity amplitude measure of $\sim$2 m s$^{-1}$. The analysis includes discussion of the fitting quality and model adequacy. Our derived absolute parameters for Kepler-2 are as follows: $M_p$ (Jupiter) 1.80 $\pm$ 0.13; $R_{\star}$ 1.46 $\pm 0.08 \times 10^6$ km; $R_p$ 1.15 $\pm 0.07 \times 10^5$ km. These values imply somewhat larger and less condensed bodies than previously catalogued, but within reasonable error estimates of such literature parameters. We find also tidal, reflection and Doppler effect parameters, showing that the optimal model specification differs slightly from a `cleaned' model that reduces the standard deviation of the $\sim$3600 binned light curve points to less than 0.9 ppm. We consider these slight differences, making comparisons with the hot-jupiter systems Kepler-1 (TrES-2) and 13.
- [22] arXiv:2004.07979 [pdf, other]
-
Title: The PAU Survey: Photometric redshifts using transfer learning from simulationsAuthors: M. Eriksen, A. Alarcon, L. Cabayol, J. Carretero, R. Casas, F. J. Castander, J. De Vicente, E. Fernandez, J. Garcia-Bellido, E. Gaztanaga, H. Hildebrandt, H. Hoekstra, B. Joachimi, R. Miquel, C. Padilla, E. Sanchez, I. Sevilla-Noarbe, P. TalladaSubjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
In this paper we introduce the \textsc{Deepz} deep learning photometric redshift (photo-$z$) code. As a test case, we apply the code to the PAU survey (PAUS) data in the COSMOS field. \textsc{Deepz} reduces the $\sigma_{68}$ scatter statistic by 50\% at $i_{\rm AB}=22.5$ compared to existing algorithms. This improvement is achieved through various methods, including transfer learning from simulations where the training set consists of simulations as well as observations, which reduces the need for training data. The redshift probability distribution is estimated with a mixture density network (MDN), which produces accurate redshift distributions. Our code includes an autoencoder to reduce noise and extract features from the galaxy SEDs. It also benefits from combining multiple networks, which lowers the photo-$z$ scatter by 10 percent. Furthermore, training with randomly constructed coadded fluxes adds information about individual exposures, reducing the impact of photometric outliers. In addition to opening up the route for higher redshift precision with narrow bands, these machine learning techniques can also be valuable for broad-band surveys.
- [23] arXiv:2004.07990 [pdf, other]
-
Title: Electric current evolution at the footpoints of solar eruptionsComments: 27 pages, 10 figures; Accepted for publication in ApJ (13 April 2020)Subjects: Solar and Stellar Astrophysics (astro-ph.SR)
Electric currents play a critical role in the triggering of solar flares and their evolution. The aim of the present paper is to test whether the surface electric current has a surface or subsurface fixed source as predicts the circuit approach of flare physics, or is the response of the surface magnetic field to the evolution of the coronal magnetic field as the MHD approach proposes. Out of all 19 X-class flares as observed by SDO from 2011 to 2016 near the disk center, we analyzed the only 9 eruptive flares for which clear ribbon-hooks were identifiable. Flare ribbons with hooks are considered to be the footprints of eruptive flux ropes in MHD flare models. For the first time, fine measurements of time-evolution of electric currents inside the hooks in the observations as well as in the OHM 3D MHD simulation are performed. Our analysis shows a decrease of the electric current in the area surrounded by the ribbon hooks during and after the eruption. We interpret the decrease of the electric currents as due to the expansion of the flux rope in the corona during the eruption. Our analysis brings a new contribution to the standard flare model in 3D.
- [24] arXiv:2004.08006 [pdf, ps, other]
-
Title: Magnetic-field evolution with large-scale velocity circulation in a neutron-star crustSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
We examine the effects of plastic flow that appear in a neutron-star crust when a magnetic stress exceeds the threshold. The dynamics involved are described using the Navier--Stokes equation comprising the viscous-flow term, and the velocity fields for the global circulation are determined using quasi-stationary approximation.
We simulate the magnetic-field evolution by taking into consideration the Hall drift, Ohmic dissipation, and fluid motion induced by the Lorentz force. The decrease in the magnetic energy is enhanced, as the energy converts to the bulk motion energy and heat. It is found that the bulk velocity induced by the Lorentz force has a significant influence in the low-viscosity and strong-magnetic-field regimes. This effect is crucial near magnetar surfaces. - [25] arXiv:2004.08011 [pdf, ps, other]
-
Title: Improved axion haloscope search analysisComments: 7 pages, 8 figuresSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Experiment (hep-ex)
The most significant and practical figure of merit in axion haloscope searches is the scanning rate, because of the unknown axion mass. Even under the best experimental parameters, the only way to improve the figure of merit is to increase the experimentally designed signal to noise ratio in the axion haloscope search analysis procedure. In this paper, we report an improved axion haloscope search analysis, developed using CAPP-8TB. By fully incorporating the known negative correlations induced by the background parametrizations, the figure of merit of the CAPP-8TB haloscope search was increased by about 17\% for the scanning rate, with about an 8\% improvement in the signal to noise ratio. In addition, the physics results can be retrieved directly from the standard Gaussian statistics of the data, at any confidence level.
- [26] arXiv:2004.08014 [pdf, other]
-
Title: Modeling relativistic contributions to the halo power spectrum dipoleComments: 45 pages, 10 figuresSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc)
We study the power spectrum dipole of an N-body simulation which includes relativistic effects through ray-tracing and covers the low redshift Universe up to $z_{\rm max} = 0.465$ (RayGalGroup simulation). We model relativistic corrections as well as wide-angle, evolution, window and lightcone effects. Our model includes all relativistic corrections up to third-order including third-order bias expansion. We consider all terms which depend linearly on $\mathcal{H}/k$ (weak field approximation). We also study the impact of 1-loop corrections to the matter power spectrum for the gravitational redshift and transverse Doppler effect. We found wide-angle and window function effects to significantly contribute to the dipole signal. When accounting for all contributions, our dipole model can accurately capture the gravitational redshift and Doppler terms up to the smallest scales included in our comparison ($k=0.48\,h{\rm Mpc}^{-1}$), while our model for the transverse Doppler term is less accurate. We find the Doppler term to be the dominant signal for this low redshift sample. We use Fisher matrix forecasts to study the potential for the future Dark Energy Spectroscopic Instrument (DESI) to detect relativistic contributions to the power spectrum dipole. A conservative estimate suggests that the DESI-BGS sample should be able to have a detection of at least $4.4\sigma$, while more optimistic estimates find detections of up to $10\sigma$. Detecting these effects in the galaxy distribution allows new tests of gravity on the largest scales, providing an interesting additional science case for galaxy survey experiments.
- [27] arXiv:2004.08026 [pdf, other]
-
Title: Pixel-based spectral characterization of mid-infrared Si array detectors for astronomical observations in spaceComments: 14 pages, 10 figures. Accepted for publication in PASPSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)
Mid-infrared (IR) array detectors have been used for astronomical observations in space. However, the uniformities of their spectral response curves have not been investigated in detail, the understanding of which is important for spectroscopic observations using large array formats. We characterize the spectral responses of all the pixels in IR array detectors using a Fourier transform infrared spectrometer and cryogenic optics for measurements at high signal-to-noise ratios. We measured the spectral responses of the Si:As impurity band conduction (IBC) array, a flight back-up detector for AKARI/IRC. As a result, we find that the Si:As array has intrinsic variations in the spectral response along the row and column directions of the array. We also find that the cutoff wavelength of the Si:As IBC array depends on the intensity of the incident light.
- [28] arXiv:2004.08048 [pdf, ps, other]
-
Title: KIC~8975515: a fast-rotating ($γ$ Dor - $δ$ Sct) hybrid star with Rossby modes and a slower $δ$ Sct companion in a long-period orbitComments: Accepted to publish on A \& ASubjects: Solar and Stellar Astrophysics (astro-ph.SR); Instrumentation and Methods for Astrophysics (astro-ph.IM)
{KIC~8975515 is a \emph{Kepler} double-lined spectroscopic binary system with hybrid pulsations. Two components have similar atmospheric properties (T$_{\rm eff}$ $\sim$ 7400~K), and one of them is a fast rotator ($v\sin i = 162$ versus 32 km/s). Our aim is to study the \emph {Kepler} light curve in great detail in order to determine the frequencies of the pulsations, to search for regular spacing patterns in the Fourier spectrum, if any, and to discuss their origin in the context of binarity and fast rotation. In this paper, we study the properties of the stellar pulsations based on a careful analysis in the low-, intermediate- and high-frequency regions of the Fourier spectrum. This is done by performing repeated frequency-search analyses with successive prewhitenings of all the significant frequencies detected in the spectrum. Moreover, we searched for regular period spacings among the $g$ modes, as well as frequency splitting among the $g$ and $p$ modes. In the low-frequency regime, five regular period spacing patterns including one series of prograde $g$ modes and four series of retrograde $r$ modes were detected. The $r$ modes are well-distributed with respect to the harmonics of the rotational frequency of the fast-rotating star $f_{\rm rot}$ = 1.647 d$^{-1}$. The dominant $g$ mode is $f_{2}$ = 2.37 d$^{-1}$. The strongest p mode, at $f_{1}$ = 13.97 d$^{-1}$, forms a singlet. In the high-frequency region, we identified two multiplets of regularly split $p$ modes with mean frequency spacings of 0.42 d$^{-1}$ and 1.65 d$^{-1}$. We detected some series of retrograde $r$ and prograde $g$ modes as well as two multiplets of $p$ modes with frequency spacings related to the stellar rotation of both components of the twin system KIC~8975515. We identified the fast-rotating component as a hybrid pulsator with $r$ modes and the slowly-rotating component as a $\delta$ Sct pulsator.
- [29] arXiv:2004.08050 [pdf, other]
-
Title: Stellar migrations and metal flows -- Chemical evolution of the thin disc of a simulated Milky Way analogous galaxyComments: 15 pages, 13 figures, resubmitted to MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA)
In order to understand the roles of metal flows in galaxy formation and evolution, we analyse our self-consistent cosmological chemo-dynamical simulation of a Milky Way like galaxy during its thin-disc phase. Our simulated galaxy disc qualitatively reproduces the variation of the dichotomy in [$\alpha$/Fe]-[Fe/H] at different Galactocentric distances as derived by APOGEE-DR16, as well as the stellar age distribution in [$\alpha$/Fe]-[Fe/H] from APOKASC-2. The disc grows from the inside out, with a radial gradient in the star-formation rate during the entire phase. Despite the radial dependence, the outflow-to-infall ratio of metals in our simulated halo shows a universal (time-independent) profile scaling with the disc growth. The simulated disc undergoes two modes of gas inflow: (i) an infall of metal-poor and relatively low-[$\alpha$/Fe] gas, and (ii) a radial flow where already chemically-enriched gas moves inwards with an average velocity of $\sim0.7$ km/s. Moreover, we find that stellar migrations mostly happen outwards, on typical time scales of $\sim5$ Gyr. Our predicted radial metallicity gradients agree with the observations from APOGEE-DR16, and the main effect of stellar migrations is to flatten the radial metallicity profiles by 0.05 dex/kpc in the slopes. We also show that the effect of migrations can appear more important in [$\alpha$/Fe] than in the [Fe/H]-age relation of thin-disc stars.
- [30] arXiv:2004.08137 [pdf, other]
-
Title: Using all-sky optical observations for automated orbit determination and prediction for satellites in Low Earth OrbitComments: Proc. 1st NEO and Debris Detection Conference, ESA Darmstadt, Germany, 22-24 January 2019, 7 pages, 6 figuresSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)
We have used an existing, robotic, multi-lens, all-sky camera system, coupled to a dedicated data reduction pipeline, to automatically determine orbital parameters of satellites in Low Earth Orbit (LEO). Each of the fixed cameras has a Field of View of 53 x 74 degrees, while the five cameras combined cover the entire sky down to 20 degrees from the horizon. Each of the cameras takes an image every 6.4 seconds, after which the images are automatically processed and stored. We have developed an automated data reduction pipeline that recognizes satellite tracks, to pixel level accuracy ($\sim$ 0.02 degrees), and uses their endpoints to determine the orbital elements in the form of standardized Two Line Elements (TLEs). The routines, that use existing algorithms such as the Hough transform and the Ransac method, can be used on any optical dataset.
For a satellite with an unknown TLE, we need at least two overflights to accurately predict the next one. Known TLEs can be refined with every pass to improve collision detections or orbital decay predictions, for example. For our current data analysis we have been focusing on satellites in LEO, where we are able to recover between 50% and 80% of the known overpasses during twilight. We have been able to detect LEO satellites down to 7th visual magnitude. Higher objects, up to geosynchronous orbit, were visually observed, but are currently not being automatically picked up by our reduction pipeline. We expect that with further improvements to our data reduction, and potentially with longer integration times and/or different optics, the instrumental set-up can be used for tracking a significant fraction of satellites up to geosynchronous orbit. - [31] arXiv:2004.08139 [pdf, other]
-
Title: Emulation of cosmological mass maps with conditional generative adversarial networksComments: Accepted at the Workshop at the 33rd Conference on Neural Information Processing Systems (NeurIPS), December 14, 2019, this https URLSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Machine Learning (cs.LG); Image and Video Processing (eess.IV)
Mass maps created using weak gravitational lensing techniques play a crucial role in understanding the evolution of structures in the universe and our ability to constrain cosmological models. The mass maps are based on computationally expensive N-body simulations, which can create a computational bottleneck for data analysis. Simulation-based emulators of observables are starting to play an increasingly important role in cosmology, as the analytical predictions are expected to reach their precision limits for upcoming experiments. Modern deep generative models, such as Generative Adversarial Networks (GANs), have demonstrated their potential to significantly reduce the computational cost of generating such simulations and generate the observable mass maps directly. Until now, most GAN approaches produce simulations for a fixed value of the cosmological parameters, which limits their practical applicability. We instead propose a new conditional model that is able to generate simulations for arbitrary cosmological parameters spanned by the space of simulations. Our results show that unseen cosmologies can be generated with high statistical accuracy and visual quality. This contribution is a step towards emulating weak lensing observables at the map level, as opposed to the summary statistic level.
- [32] arXiv:2004.08168 [pdf, other]
-
Title: A Bayesian comparison between $Λ$CDM and phenomenologically emergent dark energy modelsComments: Accepted in EPJCSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc)
In this work we examine the recently proposed phenomenological emergent dark energy (PEDE) model by \cite{Li:2019yem}, using the latest observational data in both expansion and perturbation levels. Applying the statistical Bayesian evidence as well as the AIC and BIC information criteria, we compare the PEDE model with the concordance $\Lambda$CDM model in both flat and non-flat universes. We combine the observational datasets as (i) expansion data (except CMB), (ii) expansion data (including CMB) and (iii) expansion data jointed to the growth rate dataset. Our statistical results show that the flat- $\Lambda$CDM model is still the best model. In the case of expansion data (including CMB), we observe that the flat- PEDE model is well consistent with observations as well as the concordance $\Lambda$CDM universe. While in the cases of (i) and (iii), the PEDE models in both of the flat and non-flat geometries are not favored. In particular, we see that in the perturbation level the PEDE model can not fit the observations as equally as standard $\Lambda$CDM cosmology. As the ability of the model, we show that the PEDE models can alleviate the tension of Hubble constant value appearing between the local observations and Planck inferred estimation in standard cosmology.
- [33] arXiv:2004.08171 [pdf, other]
-
Title: Introducing the HD+B model for pulsar wind nebulae: a hybrid hydrodynamics/radiative approachComments: 15 pages, 9 figuresSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
Identification and characterization of a rapidly increasing number of pulsar wind nebulae is, and will continue to be, a challenge of high-energy gamma-ray astrophysics. Given that such systems constitute -- by far -- the most numerous expected population in the TeV regime, such characterization is important not only to learn about the sources per se from an individual and population perspective, but also to be able to connect them with observations at other frequencies, especially in radio and X-rays. Also, we need to remove the emission from nebulae in highly confused regions of the sky for revealing other underlying emitters. In this paper we present a new approach for theoretical modelling of pulsar wind nebulae: a hybrid hydrodynamic-radiative model able to reproduce morphological features and spectra of the sources, with relatively limited numerical cost.
- [34] arXiv:2004.08182 [pdf, other]
-
Title: Stellar angular momentum distribution linked to galaxy morphologyAuthors: Sarah M. Sweet, Karl Glazebrook, Danail Obreschkow, Deanne B. Fisher, Andreas Burkert, Claudia D. P. Lagos, Juan M. Espejo SalcedoComments: 19 pages, 11 figures, accepted for publication in MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA)
We study the spatially-resolved stellar specific angular momentum $j_*$ in a high-quality sample of 24 CALIFA galaxies covering a broad range of visual morphology, accounting for stellar velocity and velocity dispersion. The shape of the spaxel-wise probability density function of normalised $s=j_*/j_{*mean}$, PDF($s$), deviates significantly from the near-universal initial distribution expected of baryons in a dark matter halo and can be explained by the expected baryonic effects in galaxy formation that remove and redistribute angular momentum. Further we find that the observed shape of the PDF($s$) correlates significantly with photometric morphology, where late-type galaxies have PDF($s$) that is similar to a normal distribution, whereas early types have a strongly-skewed PDF($s$) resulting from an excess of low-angular momentum material. Galaxies that are known to host pseudobulges (bulge Sersic index $n_b <2.2$) tend to have less skewed bulge PDF($s$), with skewness $(b_{1rb})\lesssim0.8$. The PDF($s$) encodes both kinematic and photometric information and appears to be a robust tracer of morphology. Its use is motivated by the desire to move away from traditional component-based classifications which are subject to observer bias, to classification on a galaxy's fundamental (stellar mass, angular momentum) properties. In future, PDF($s$) may also be useful as a kinematic decomposition tool.
- [35] arXiv:2004.08203 [pdf, other]
-
Title: 'Bonn' Optimized Stellar Tracks (BoOST). Simulated Populations of Massive and Very Massive Stars as Input for Astrophysical ApplicationsComments: Submitted to ApJ. We welcome feedback and requests from the communitySubjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE); Instrumentation and Methods for Astrophysics (astro-ph.IM)
Massive and very massive stars can play important roles in stellar populations by ejecting strong stellar winds and exploding in energetic phenomena. It is therefore of high importance that their behaviour is properly accounted for in synthetic model populations. Here we present nine grids of stellar evolutionary model sequences, together with finely resolved interpolated sequences and synthetic populations, of stars with 9-500 Msun and with metallicities ranging from Solar down to 1/250 Solar. The stellar models were computed with the 'Bonn' evolutionary code (covering core-hydrogen- and core-helium-burning phases, both complete). Post-processing for publication has been done using optimized methods, developed by our team, for massive and very massive stars. Interpolation and population synthesis were also performed on the models by our newly developed routine synStars. Eight of the grids represent slowly rotating massive stars with normal/classical evolution, while one grid represents fast rotating, chemically-homogeneously evolving models. Apart from the common stellar parameters such as mass, radius, surface temperature, luminosity and mass loss rate, we present stellar wind properties such as estimated wind velocity and kinetic energy of the wind. Additionally, we provide complete chemical yields of 34 isotopes, and estimates for the masses of the compact object remnants. The 'Bonn' Optimized Stellar Tracks (BoOST) project is published as simple tables - including stellar models, interpolated tracks and synthetic populations - thus ideal for further scientific applications. For example, star-formation studies could be done with BoOST to cover broad metallicity ranges, and so could be simulations of high-redshift galaxies. Additionally, gravitational-wave event rate predictions could be refined using BoOST by accounting for very massive stars at low-metallicity.
- [36] arXiv:2004.08218 [pdf, other]
-
Title: Inertial modes of a freely rotating ellipsoidal planet and their relation to nutationsComments: 17 pages, 4 figures, submitted to Planetary Science Journal (AAS)Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Fluid Dynamics (physics.flu-dyn)
We compute the inertial modes of a freely rotating two-layer planetary model with an ellipsoidal inviscid fluid core and a perfectly rigid mantle. We derive analytical formulae for the frequencies of the Free Core Nutation (FCN) and Chandler Wobble (CW) which are valid to all orders in the core and mantle ellipticity and we show how the FCN and CW are the direct generalisation of the purely fluid Spin-Over mode (SO) and of the Eulerian Wobble (EW) to the case where the mantle can oscillate freely around a state of steady rotation. Through a numerical computation for an axisymmetric (oblate spheroidal) planet, we demonstrate that all other inertial modes of the steadily rotating fluid core are also free modes of the freely rotating two-layer planet.
- [37] arXiv:2004.08229 [pdf, ps, other]
-
Title: Comparison of pulsar parameters for some anomalous typesComments: 22 pages, 27 figuresSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
The comparative analysis of parameters is carried out for two samples of radio pulsars. Objects of the first sample have periods P > 2 sec, the second is characterized by magnetic fields at the neutron star surface $Bs > 4.4\times10^{13}$ G. The main goal of this analysis is to find some differences between normal pulsars and anomalous X-ray pulsars (AXP) and soft gamma-ray repeaters (SGR) with the similar values of periods and magnetic fields. It is shown that the dependence of period derivatives on periods for pulsars with long periods is $dP/dt \propto P^{1.67}$. This means that we must search for another braking mechanism differing from the magnetic dipole one which gives $dP/dt \propto P^{-1}$ or use some specific distributions of parameters. On the other hand, radio pulsars with strong magnetic fields and AXP/SGR can be described by the magnetic dipole model. Radio pulsars with P > 2 sec have ages on average two orders of magnitude higher than objects with $Bs > 4.4 \times 10^{13}$ G and are located much higher above the Galactic plane. The obtained results show that the main feature of AXP/SGR is the strong magnetic field and not the large period.
- [38] arXiv:2004.08230 [pdf, other]
-
Title: Estimating the values and variations of neutron star observables by dense nuclear matter propertiesComments: 13 pages, 6 figures, 4 tablesSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Phenomenology (hep-ph); Nuclear Theory (nucl-th)
Recent NICER observation data on PSR J0030+0451 has recently added a unique mass-radius constraint on the properties of the superdense nuclear matter exist in the compact stars interior. Such a macroscopic data restrict further the models, interactions, and its parameters, however, because of the masquarade problem with reasonable margin. The aim of this paper is to identify the origin and quantified the magnitude of the theoretical uncertainties. A detailed study on the effect of different interaction terms and the nuclear parameter values in the Lagrangian of the extended $\sigma$-$\omega$ model is presented here. The equation of state was inserted to the Tolman--Oppenheimer--Volkoff equation and observable parameters of the neutron star were calculated. We identified, that the optimal Landau effective mass is the most relevant physical parameter modifying the macroscopic observable values. Moreover, the compressibility and symmetry energy terms just generate one-one order of magnitude smaller effect to this, respectively. We calculated the linear relations between the maximal mass of a compact star and these microscopic nuclear parameter values within the physical relevant parameters range. Based on observational data on masses, we estimated the magnitude of the radii of PSR J1614-2230, PSR J0348+0432, and PSR J0740+6620 including theoretical uncertainties arising from the interaction terms of the nuclear matter and their parameter values choice.
- [39] arXiv:2004.08242 [pdf, other]
-
Title: Spectral Modeling of Charge Exchange in the Central Region of M51Authors: Hang Yang (1 and 2), Shuinai Zhang (1 and 3), Li Ji (1 and 3) ((1) Purple Mountain Observatory, CAS, (2) School of Astronomy and Space Science, University of Science and Technology of China, (3) Key Laboratory of Dark Matter and Space Astronomy, CAS)Subjects: Astrophysics of Galaxies (astro-ph.GA)
Charge exchange (CX) emission reveals the significant interaction between neutral and ionized interstellar medium (ISM) components of the dense, multiphase, circumnuclear region of a galaxy. We use a model including a thermal and a CX components to describe the high-resolution XMM-Newton/RGS spectrum of the diffuse emission in the central region of M51. Representative signatures of CX emission -- especially the prominent OVII forbidden line and the excess emission in the OVIII Ly$\gamma$ lines -- can be well explained by the model. Combined with the Chandra images in the OVIII and the OVII bands, we find the soft X-ray emission is dominated by the jet-driven outflow and its interaction with the ambient neutral material. The jet-driven outflow itself is likely a thermal plasma of $\sim 0.59$ keV, with mostly sub-solar abundances. It runs into the ambient neutral gas, and produces significant CX emission that accounts for one-fifth of the diffuse X-ray emission in the 7--28 {\AA} band. The effective interface area in the CX process is one order of magnitude greater than the geometrical surface area of the jet-driven outflow. The tenuous outflow driven by the nuclear star formation may also contribute a small portion to both the diffuse thermal and CX emission. The photoionization by the active galactic nuclei (AGNs) and the resonance scattering by the hot gas itself are disfavored, though the effects from past AGN events may not be ruled out.
- [40] arXiv:2004.08254 [pdf, other]
-
Title: Event reconstruction for KM3NeT/ORCA using convolutional neural networksAuthors: Sebastiano Aiello, Arnauld Albert, Sergio Alves Garre, Zineb Aly, Fabrizio Ameli, Michel Andre, Giorgos Androulakis, Marco Anghinolfi, Mancia Anguita, Gisela Anton, Miquel Ardid, Julien Aublin, Christos Bagatelas, Giancarlo Barbarino, Bruny Baret, Suzan Basegmez du Pree, Meriem Bendahman, Edward Berbee, Vincent Bertin, Simone Biagi, Andrea Biagioni, Matthias Bissinger, Markus Boettcher, Jihad Boumaaza, Mohammed Bouta, Mieke Bouwhuis, Cristiano Bozza, Horea Branzas, Ronald Bruijn, Jürgen Brunner, Ernst-Jan Buis, Raffaele Buompane, Jose Busto, Barbara Caiffi, David Calvo, Antonio Capone, Víctor Carretero, Paolo Castaldi, Silvia Celli, Mohamed Chabab, Nhan Chau, Andrew Chen, Silvio Cherubini, Vitaliano Chiarella, Tommaso Chiarusi, Marco Circella, Rosanna Cocimano, Joao Coelho, Alexis Coleiro, et al. (183 additional authors not shown)Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Instrumentation and Detectors (physics.ins-det)
The KM3NeT research infrastructure is currently under construction at two locations in the Mediterranean Sea. The KM3NeT/ORCA water-Cherenkov neutrino detector off the French coast will instrument several megatons of seawater with photosensors. Its main objective is the determination of the neutrino mass ordering. This work aims at demonstrating the general applicability of deep convolutional neural networks to neutrino telescopes, using simulated datasets for the KM3NeT/ORCA detector as an example. To this end, the networks are employed to achieve reconstruction and classification tasks that constitute an alternative to the analysis pipeline presented for KM3NeT/ORCA in the KM3NeT Letter of Intent. They are used to infer event reconstruction estimates for the energy, the direction, and the interaction point of incident neutrinos. The spatial distribution of Cherenkov light generated by charged particles induced in neutrino interactions is classified as shower- or track-like, and the main background processes associated with the detection of atmospheric neutrinos are recognized. Performance comparisons to machine-learning classification and maximum-likelihood reconstruction algorithms previously developed for KM3NeT/ORCA are provided. It is shown that this application of deep convolutional neural networks to simulated datasets for a large-volume neutrino telescope yields competitive reconstruction results and performance improvements with respect to classical approaches.
- [41] arXiv:2004.08293 [pdf, other]
-
Title: Quarkyonic Matter Equation of State in Beta-EquilibriumComments: 11 pages, 11 figuresSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
Quark matter may appear due to a hadronic-quark transition in the core of a hybrid star. Quarkyonic matter is an approach in which both quarks and nucleons appear as quasi-particles in a crossover transition, and provides an explicit realization of early ideas concerning quark matter (e.g., the MIT bag model). This description has recently been employed by McLerran and Reddy to model chargeless (pure neutron) matter with an approach that has the virtue that the speed of sound rises quickly at a neutron-quark transition so as to satisfy observational constraints on the neutron star maximum mass ($\gtrsim2M_\odot$) and the radius of a $1.4M_\odot$ star ($R_{1.4}\lesssim 13.5$ km). Traditional models involving first-order transitions result in softer pressure-energy density relations that have difficulty satisfying these constraints except with very narrow choices of parameters. We propose a variation of quarkyonic matter involving protons and leptons whose energy can be explicitly minimized to achieve both chemical and beta equilibrium, which cannot be done in the chargeless formulation. Quarkyonic stellar models are able to satisfy observed mass and radius constraints with a wide range of model parameters, avoiding the obligatory fine-tuning of conventional hybrid star models, including requiring the transition density to be very close to the nuclear saturation density. Our formulation fits experimental and theoretical properties of the nuclear symmetry energy and pure neutron matter, and contains as few as three free parameters. This makes it an ideal tool for the study of high-density matter that is an efficient alternative to piecewise polytrope or spectral decomposition methods.
- [42] arXiv:2004.08321 [pdf, other]
-
Title: The local-filament pattern in the anomalous transparency of the Universe for energetic gamma raysAuthors: Sergey TroitskyComments: 8 pages revtexSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Phenomenology (hep-ph)
The propagation length of high-energy photons through the Universe is limited by the absorption due to $e^+e^-$ pair production on extragalactic background radiation. Previous studies reported some discrepancies between predicted and observed absorption, suggesting explanations in terms of new physics. However, these effects are dominated by a limited number of observed sources, while many do not show any discrepancy. Here, we consider the distribution in the sky of these apparently anomalous objects, selected in two very different approaches: the study of unphysical hardenings at distance-dependent energies in deabsorbed spectra of TeV blazars, and the observation of ultra-high-energy air showers from the directions of BL Lac type objects. In both cases, directions to the anomalous sources follow the projected local distribution of galaxies, meaning that the distant sources, contributing to the anomalies, are seen through the local filament. This is in line with the proposed earlier explanation of the anomalies based on mixing of photons with axion-like particles in the filament's magnetic field.
- [43] arXiv:2004.08327 [pdf, other]
-
Title: Secular dynamics of hierarchical multiple systems composed of nested binaries, with an arbitrary number of bodies and arbitrary hierarchical structure. III. Suborbital effects: hybrid integration techniques and orbit-averaging correctionsAuthors: Adrian S. HamersComments: Accepted for publication in MNRAS. 15 pages, 4 figures. Code can be found at this https URLSubjects: Earth and Planetary Astrophysics (astro-ph.EP); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)
The SecularMultiple code, presented in two previous papers of this series, integrates the long-term dynamical evolution of multiple systems with any number of bodies and hierarchical structure, provided that the system is composed of nested binaries. In the formalism underlying SecularMultiple, we previously averaged over all orbits in the system. This approximation significantly speeds up numerical integration of the equations of motion, making large population synthesis studies possible. However, the orbit averaging approximation can break down when the secular evolution timescale of the system is comparable to or shorter than any of the orbital periods in the system. Here, we present an update to SecularMultiple in which we incorporate hybrid integration techniques, and orbit-averaging corrections. With this update, the user can specify which orbits should be integrated directly (without averaging), or assuming averaged orbits. For orbits that are integrated directly, we implemented two integration techniques, one which is based on the regularised Kustaanheimo-Stiefel equations of motion in element form. We also implemented analytical orbit-averaging corrections for pairwise interactions to quadrupole order. The updates presented here provide more flexibility for integrating the long-term dynamical evolution of hierarchical multiple systems. By effectively combining direct integration and orbit averaging the long-term evolution can be accurately computed, but with significantly lower computational cost compared to existing direct N-body codes. We give a number of examples in which the new features are beneficial. Our updated code, which is written in C++ supplemented with a user-friendly interface in Python, is freely available.
- [44] arXiv:2004.08331 [pdf, ps, other]
-
Title: The spatial distribution of quasi-biennial oscillations in the high-latitude solar activityComments: MNRASSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
Quasi-biennial oscillations (QBOs) are considered as a fundamental mode of solar magnetic activity at low latitudes ($\leq50^\circ$). However, the evolutionary aspect and the hemispheric distribution of solar QBOs at high latitudes ($\geq60^\circ$) are rarely studied. Here, a relatively novel time-frequency analysis technique, named the synchrosqueezed wavelet transform, is applied to extract the main components of the polar faculae in the northern and southern hemispheres for the time interval from August 1951 to December 1998. It is found as the following: (1) Apart from the 22-year Hale cycle, the 17-year extended activity cycle, and the 11-year Schwabe cycle, the QBOs have been estimated as a prominent timescale of solar magnetic activity at high latitudes; (2) the QBOs of the polar faculae are coherent in the two hemispheres, but the temporal (phase) and the spatial (amplitude) variations of solar QBOs occur unevenly on both hemispheres; and (3) for the 11-year period mode, the northern hemisphere begins three months earlier than that in the southern one. Moreover, the spatial and temporal distributions of the hemispheric QBOs differ from those of the 11-year Schwabe cycle mode in the two hemispheres. Our findings could be helpful to improve our knowledge on the physical origin of the spatial distribution of solar QBOs at high latitudes, and could also provide more constraints on solar dynamo models introduced to characterize the different components of the solar magnetic activity cycle.
- [45] arXiv:2004.08342 [pdf, other]
-
Title: GW190412: Observation of a Binary-Black-Hole Coalescence with Asymmetric MassesComments: 19 pages, 11 figuresSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc)
We report the observation of gravitational waves from a binary-black-hole coalescence during the first two weeks of LIGO's and Virgo's third observing run. The signal was recorded on April 12, 2019 at 05:30:44 UTC with a network signal-to-noise ratio of 19. The binary is different from observations during the first two observing runs most notably due to its asymmetric masses: a ~30 solar mass black hole merged with a ~8 solar mass black hole companion. The more massive black hole rotated with a dimensionless spin magnitude between 0.17 and 0.59 (90% probability). Asymmetric systems are predicted to emit gravitational waves with stronger contributions from higher multipoles, and indeed we find strong evidence for gravitational radiation beyond the leading quadrupolar order in the observed signal. A suite of tests performed on GW190412 indicates consistency with Einstein's general theory of relativity. While the mass ratio of this system differs from all previous detections, we show that it is consistent with the population model of stellar binary black holes inferred from the first two observing runs.
- [46] arXiv:2004.08363 [pdf, other]
-
Title: $H_0$ Tension, Phantom Dark Energy and Cosmological Parameter DegeneraciesComments: 11 pages, 7 Figures. The numerical analysis files used for the production of the figures of the paper may be downloaded from this https URLSubjects: 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)
Phantom dark energy can produce amplified cosmic acceleration at late times, thus increasing the value of $H_0$ favored by CMB data and releasing the tension with local measurements of $H_0$. We show that the best fit value of $H_0$ in the context of the CMB power spectrum is degenerate with a constant equation of state parameter $w$, in accordance with the approximate effective linear equation $H_0 + 30.93\; w - 36.47 = 0$ ($H_0$ in $km \; sec^{-1} \; Mpc^{-1}$). This equation is derived by assuming that both $\Omega_{0 \rm m}h^2$ and $d_A=\int_0^{z_{rec}}\frac{dz}{H(z)}$ remain constant (for invariant CMB spectrum) and equal to their best fit Planck/$\Lambda$CDM values as $H_0$, $\Omega_{0 \rm m}$ and $w$ vary. For $w=-1$, this linear degeneracy equation leads to the best fit $H_0=67.4 \; km \; sec^{-1} \; Mpc^{-1}$ as expected. For $w=-1.22$ the corresponding predicted CMB best fit Hubble constant is $H_0=74 \; km \; sec^{-1} \; Mpc^{-1}$ which is identical with the value obtained by local distance ladder measurements while the best fit matter density parameter is predicted to decrease since $\Omega_{0 \rm m}h^2$ is fixed. We verify the above $H_0-w$ degeneracy equation by fitting a $w$CDM model with fixed values of $w$ to the Planck TT spectrum showing also that the quality of fit ($\chi^2$) is similar to that of $\Lambda$CDM. However, when including SnIa, BAO or growth data the quality of fit becomes worse than \lcdm when $w< -1$. Finally, we generalize the $H_0-w(z)$ degeneracy equation for $w(z)=w_0+w_1\; z/(1+z)$ and identify analytically the full $w_0-w_1$ parameter region (straight line) that leads to a best fit $H_0=74\; km \; sec^{-1} \; Mpc^{-1}$ in the context of the Planck CMB spectrum. This exploitation of $H_0-w(z)$ degeneracy can lead to immediate identification of all parameter values of a given $w(z)$ parametrization that can potentially resolve the $H_0$ tension.
Cross-lists for Mon, 20 Apr 20
- [47] arXiv:2004.07655 (cross-list from gr-qc) [pdf, other]
-
Title: Vector perturbations in bouncing cosmologyAuthors: Nelson Pinto-Neto, Júlio C. Fabris, Júnior D. Toniato, Gustavo. S. Vicente, Sandro D. P. VitentiComments: 10 pagesSubjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Theory (hep-th)
An old question surrounding bouncing models concerns their stability under vector perturbations. Considering perfect fluids or scalar fields, vector perturbations evolve kinematically as $a^{-2}$, where $a$ is the scale factor. Consequently, a definite answer concerning the bounce stability depends on an arbitrary constant, therefore, there is no definitive answer. In this paper, we consider a more general situation where the primeval material medium is a non-ideal fluid, and its shear viscosity is capable of producing torque oscillations, which can create and dynamically sustain vector perturbations along cosmic evolution. In this framework, one can set that vector perturbations have a quantum mechanical origin, coming from quantum vacuum fluctuations in the far past of the bouncing model, as it is done with scalar and tensor perturbations. Under this prescription, one can calculate their evolution during the whole history of the bouncing model, and precisely infer the conditions under which they remain linear before the expanding phase. It is shown that such linearity conditions impose constraints on the free parameters of bouncing models, which are mild, although not trivial, allowing a large class of possibilities. Such conditions impose that vector perturbations are also not observationally relevant in the expanding phase. The conclusion is that bouncing models are generally stable under vector perturbations. As they are also stable under scalar and tensor perturbations, we conclude that bouncing models are generally stable under perturbations originated from quantum vacuum perturbations in the far past of their contracting phase.
- [48] arXiv:2004.07842 (cross-list from hep-th) [pdf, other]
-
Title: Towards a unitary, renormalizable and ultraviolet-complete quantum theory of gravityAuthors: Christian F. SteinwachsComments: 44 pages, 7 figures, 2 tablesSubjects: 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)
For any fundamental quantum field theory, unitarity, renormalizability, and relativistic invariance are considered to be essential properties. Unitarity is inevitably connected to the probabilistic interpretation of the quantum theory, while renormalizability guarantees its completeness. Relativistic invariance, in turn, is a symmetry which derives from the structure of spacetime. So far, the perturbative attempt to formulate a fundamental local quantum field theory of gravity based on the metric field seems to be in conflict with at least one of these properties. In quantum Ho\v{r}ava gravity, a quantum Lifshitz field theory of gravity characterized by an anisotropic scaling between space and time, unitarity and renormalizability can be retained while Lorentz invariance is sacrificed at high energies and must emerge only as approximate symmetry at low energies. I review various approaches to perturbative quantum gravity with a particular focus on recent progress in the quantization of Ho\v{r}ava gravity, supporting its theoretical status as a unitary, renormalizable and ultraviolet-complete quantum theory of gravity.
- [49] arXiv:2004.07844 (cross-list from hep-ph) [pdf, other]
-
Title: Gravitational waves from the fragmentation of axion-like particle dark matterComments: 32 pages, 10 figuresSubjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
The misalignment mechanism allows for the efficient, and usually very cold, production of light scalar bosons, such as axion-like particles (ALPs), making them an appealing dark matter candidate. However, in certain cases, such as in the presence of a monodromy, the self-interactions of ALPs can be sufficiently strong such that the homogeneous field fragments soon after the onset of oscillations. The resulting large inhomogeneities can lead to the production of gravitational waves (GWs). We investigate the nonlinear dynamics of fragmentation, as well as of the subsequent turbulent regime, and calculate the stochastic GW background that is produced from this process. The GW background can be enhanced if the time evolution features an extended intermediate phase of ultrarelativistic dynamics due to a small mass at the bottom of the potential. Yet, this enhancement is limited by the requirement that the dark matter remains sufficiently cold. In some cases the resulting GWs may be within reach of future GW detectors, allowing a complementary probe of this type of dark matter.
- [50] arXiv:2004.07863 (cross-list from hep-ph) [pdf, other]
-
Title: Degenerate Fermion Dark Matter from a Broken $U(1)_{\rm B-L}$ Gauge SymmetryComments: 25 pages, 8 figures, 2 tablesSubjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
The extension of the Standard model by assuming $U(1)_{\rm B-L}$ gauge symmetry is very well-motivated since it naturally explains the presence of heavy right-handed neutrinos required to account for the small active neutrino masses via the seesaw mechanism and thermal leptogenesis. Traditionally, we introduce three right handed neutrinos to cancel the $[U(1)_{\rm B-L}]^3$ anomaly. However, it suffices to introduce two heavy right-handed neutrinos for these purposes and therefore we can replace one right-handed neutrino by new chiral fermions to cancel the $U(1)_{\rm B-L}$ gauge anomaly. Then, one of the chiral fermions can naturally play a role of a dark matter candidate. In this paper, we demonstrate how this framework produces a dark matter candidate which can address the so-called "core-cusp problem". As one of the small scale problems that $\Lambda$CDM paradigm encounters, it may imply an important clue for a nature of dark matter. One of resolutions among many is hypothesizing that sub-keV fermion dark matter halos in dwarf spheroidal galaxies are in (quasi) degenerate configuration. We show how the degenerate sub-keV fermion dark matter candidate can be non-thermally originated in our model and thus can be consistent with Lyman-$\alpha$ forest observation. Thereby, the small neutrino mass, baryon asymmetry, and the sub-keV dark matter become consequences of the broken B-L gauge symmetry.
- [51] arXiv:2004.07867 (cross-list from gr-qc) [pdf, other]
-
Title: Testing $F(Q)$ gravity with redshift space distortionsComments: 6 pages, 5 figuresSubjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
A Bayesian statistical analysis using redshift space distortions data is performed to test a model of Symmetric Teleparallel Gravity where gravity is non-metrical. The cosmological background mimics a $\Lambda$CDM evolution but differences arise in the perturbations. The linear matter fluctuations are numerically evolved and the study of the growth rate of structures is analysed in this cosmological setting. The best fit parameters reveal that the $\sigma_8$ tension between Planck and Large Scale Structure data can be alleviated within this framework.
- [52] arXiv:2004.07974 (cross-list from hep-ph) [pdf, other]
-
Title: Heavy Neutral Leptons from kaon decays in the SHiP experimentComments: 19 pages, 16 figuresSubjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Experiment (hep-ex)
We calculate the signal rate of hypothetical heavy neutral leptons (HNL or sterile neutrinos) from kaon decays expected in the framework of the SHiP experiment. The kaons are produced in the hadronic shower initiated in the beam-dump mode by 400\,GeV protons from CERN SPS. For a sufficiently light HNL (when the decays are kinematically allowed) we find kaon decays to be a noticeably richer source of HNL as compared to $D$-meson decays adopted in previous studies of the HNL phenomenology at SHiP. In particular, SHiP is capable of fully exploring the central part of the kinematically allowed region of the HNL mass and mixing with active neutrinos down to the lower cosmological bound. The latter is associated with HNL decays in the early Universe to energetic products rescattering off and thus destroying light nuclei produced at the primordial nucleosynthesis. A consistency of the HNL model with smaller mixing would require either a non-standard cosmology or new ingredients in the HNL sector, closing the room for the minimal seesaw type I model with sterile neutrinos lighter than kaons.
- [53] arXiv:2004.08012 (cross-list from physics.comp-ph) [pdf, other]
-
Title: A Multistate Low-dissipation Advection Upstream Splitting Method for Ideal MagnetohydrodynamicsComments: 42 pages, 18 figures, 1 table, accepted for the publication in ApJSSubjects: Computational Physics (physics.comp-ph); Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM); Solar and Stellar Astrophysics (astro-ph.SR); Numerical Analysis (math.NA)
We develop a new numerical scheme for ideal magnetohydrodynamic (MHD) simulations, which is robust against one- and multi-dimensional shocks, and is accurate for low Mach number flows and discontinuities. The scheme belongs to a family of the advection upstream splitting method employed in computational aerodynamics, and it splits the inviscid flux in MHD equations into advection, pressure, and magnetic tension parts, and then individually evaluates mass, pressure, and magnetic tension fluxes at the interface of a computational cell. The mass flux is designed to avoid numerical shock instability in multidimension, while preserving contact discontinuity. The pressure flux possesses a proper scaling for low Mach number flows, allowing reliable simulations of nearly incompressible flows. The magnetic tension flux is built to be consistent with the HLLD approximate Riemann solver to preserve rotational discontinuity. We demonstrate various benchmark tests to verify the novel performance of the scheme. Our results indicate that the scheme must be a promising tool to tackle astrophysical systems that include both low and high Mach number flows, as well as magnetic field inhomogeneities.
- [54] arXiv:2004.08121 (cross-list from hep-ex) [pdf, other]
-
Title: New limits on the resonant absorption of solar axions obtained with a $^{169}$Tm-containing cryogenic detectorAuthors: A. H. Abdelhameed, S. V. Bakhlanov, P. Bauer, A. Bento, E. Bertoldo, L. Canonica, A. V. Derbin, I. S. Drachnev, N. Ferreiro Iachellini, D. Fuchs, D. Hauff, M. Laubenstein, D. A. Lis, I. S. Lomskaya, M. Mancuso, V. N. Muratova, S. Nagorny, S. Nisi, F. Petricca, F. Proebst, J. Rothe, V. V. Ryabchenkov, S. E. Sarkisov, D. A. Semenov, K. A. Subbotin, M .V. Trushin, E. V. Unzhakov, E. V. ZharikovComments: 7 pages, 5 figuresSubjects: High Energy Physics - Experiment (hep-ex); Solar and Stellar Astrophysics (astro-ph.SR); High Energy Physics - Phenomenology (hep-ph); Instrumentation and Detectors (physics.ins-det)
A search for resonant absorption of solar axions by $^{169}$Tm nuclei was carried out. A newly developed approach involving low-background cryogenic bolometer based on Tm$_3$Al$_5$O$_{12}$ crystal was used that allowed for significant improvement of sensitivity in comparison with previous $^{169}$Tm based experiments. The measurements performed with $8.18$ g crystal during $6.6$ days exposure yielded the following limits on axion couplings: $|g_{A\gamma} (g_{AN}^0 + g_{AN}^3) \leq 1.44 \times 10^{-14}$ GeV$^{-1}$ and $|g_{Ae} (g_{AN}^0 + g_{AN}^3) \leq 2.81 \times 10^{-16}$.
- [55] arXiv:2004.08143 (cross-list from gr-qc) [pdf, other]
-
Title: Precursory collapse in Neutron Star-Black Hole mergersComments: 13 pages, 16 figuresSubjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Theory (hep-th)
We investigate the properties of the event horizon in the merger between a large black hole and a smaller neutron star. We find that, if the star is compact enough, then, in its rest frame a horizon begins to grow inside the star before it merges with the black hole, in a manner analogous to the growth of the event horizon in stellar collapse. We may say that, ahead of its fall into the larger black hole, the neutron star begins to become a black hole itself. We discuss how the phenomenon, even if not directly observable, can be invariantly characterized. We demonstrate it quantitatively by explicitly constructing the merger event horizon in the extreme-mass-ratio limit. We show that the effect is present for realistic neutron star models and admissible values of the compactness.
- [56] arXiv:2004.08157 (cross-list from physics.flu-dyn) [pdf, other]
-
Title: Axisymmetric dynamo action is possible with anisotropic conductivityComments: 4 pages, 4 figuresJournal-ref: Physical Review Research, 2, 013321 (2020)Subjects: Fluid Dynamics (physics.flu-dyn); Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR); Geophysics (physics.geo-ph); Plasma Physics (physics.plasm-ph)
A milestone of dynamo theory is Cowling's theorem, known in its modern form as the impossibility for an axisymmetric velocity field to generate an axisymmetric magnetic field by dynamo action. Using an anisotropic electrical conductivity we show that an axisymmetric dynamo is in fact possible with a motion as simple as solid body rotation. On top of that the instability analysis can be conducted entirely analytically, leading to an explicit expression of the dynamo threshold which is the only example in dynamo theory.
- [57] arXiv:2004.08280 (cross-list from physics.space-ph) [pdf, other]
-
Title: In situ evidence of firehose instability in multiple reconnectionAuthors: Alexandra Alexandrova, Alessandro Retinò, Andrey Divin, Lorenzo Matteini, Olivier Le Contel, Hugo Breuillard, Filomena Catapano, Giulia Cozzani, Ivan Zaitsev, Jan DecaSubjects: Space Physics (physics.space-ph); Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR); Plasma Physics (physics.plasm-ph)
Energy conversion via reconnecting current sheets is common in space and astrophysical plasmas. Frequently, current sheets disrupt at multiple reconnection sites, leading to the formation of plasmoid structures between sites, which might affect energy conversion. We present in situ evidence of the firehose instability in multiple reconnection in the Earth's magnetotail. The observed proton beams accelerated in the direction parallel to magnetic field and ion-scale fluctuations of whistler type imply the development of firehose instability between two active reconnection sites. The linear wave dispersion relation, estimated for the measured plasma parameters, indicates a positive growth rate of firehose-related electromagnetic fluctuations. Simulations of temporal evolution of the observed multiple reconnection by using a 2.5D implicit particle-in-cell code show that, as the plasmoid formed between two reconnection sites evolves, the plasma at its edge becomes anisotropic and overcomes the firehose marginal stability threshold, leading to the generation of magnetic field fluctuations. The combined results of observations and simulations suggest that the firehose instability, operating between reconnection sites, converts plasma kinetic energy into energy of magnetic field fluctuations, counteracting the conversion of magnetic energy into plasma energy occurring at reconnection sites. This suggests that magnetic energy conversion in multiple reconnection can be less efficient than in the case of the single-site reconnection.
- [58] arXiv:2004.08334 (cross-list from gr-qc) [pdf, other]
-
Title: Results from the first all-sky search for continuous gravitational waves from small-ellipticity sourcesSubjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Astrophysical Phenomena (astro-ph.HE)
We present the results of an all-sky search for continuous gravitational wave signals with frequencies in the 500-1700 Hz range targeting neutron stars with ellipticity of 1e-8. The search is done on LIGO O2 data set using Falcon analysis pipeline. The results presented here double the sensitivity over LIGO O2 data results. The search is capable of detecting low ellipticity sources up to 170 pc. We establish strict upper limits which hold for worst-case signal parameters. We list outliers uncovered by the search, including several which we cannot associate with any known instrumental cause.
- [59] arXiv:2004.08369 (cross-list from hep-th) [pdf, other]
-
Title: Turning in the landscape: a new mechanism for generating Primordial Black HolesComments: 7 pages, 4 figuresSubjects: High Energy Physics - Theory (hep-th); Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc)
We propose a new model-independent mechanism for producing Primordial Black Holes during a period of multi-field inflation. The required enhancement of primordial fluctuations compared to their value at CMB scales naturally occurs when the trajectory in field space exhibits a limited period of strongly non-geodesic motion (i.e. strong bending). Such trajectories with multiple dynamical fields are motivated by the search for ultraviolet completions of inflation. The mechanism presented has numerous specific features that can be understood analytically for sufficiently smooth turns. By deriving tentative results for the Primordial Black Hole mass spectrum we study how the parameters describing the turn affect the properties of the resulting Primordial Black Hole population.
Replacements for Mon, 20 Apr 20
- [60] arXiv:0901.4085 (replaced) [pdf, other]
-
Title: Photon-axion mixing and ultra-high-energy cosmic rays from BL Lac type objects -- Shining light through the UniverseComments: Revtex 10 pages, 6 figures. V.2: QED dispersion effects taken into account; principal results unchanged. V3: misprints and sqrt(4*pi) factors in Gauss to eV conversion corrected; conclusions unchangedJournal-ref: Phys. Rev. D 84, 125019 (2011)Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Phenomenology (hep-ph)
- [61] arXiv:1603.02898 (replaced) [pdf, ps, other]
-
Title: Frequency Modulation of Directly Imaged Exoplanets: Geometric Effect as a Probe of Planetary ObliquityAuthors: Hajime KawaharaComments: 11 pages, 10 figures, A typo in Equation (A1) was fixed. The codes are provided at this https URL and this https URLJournal-ref: ApJ 822, 112 (2016)Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Earth and Planetary Astrophysics (astro-ph.EP)
- [62] arXiv:1612.01864 (replaced) [pdf, other]
-
Title: Axion-like particles and the propagation of gamma rays over astronomical distancesAuthors: S.V. TroitskyComments: 6 pages, 1 figure. Invited mini-review to be published in JETP Letters. V2: misprints and sqrt(4*pi) factors in Gauss to eV conversion corrected; conclusions unchangedJournal-ref: JETP Letters 105 (2017) 55-59; Pis'ma v ZhETF 105 (2017) 47-52Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Phenomenology (hep-ph)
- [63] arXiv:1908.04830 (replaced) [pdf, ps, other]
-
Title: Gravity theory with an extra dimension of zero lengthAuthors: Sandipan SenguptaComments: Version identical with the one to be publishedSubjects: General Relativity and Quantum Cosmology (gr-qc); Astrophysics of Galaxies (astro-ph.GA); High Energy Physics - Theory (hep-th)
- [64] arXiv:1909.04022 (replaced) [pdf, other]
-
Title: The EFT Likelihood for Large-Scale StructureComments: 53 pages (36+17), 4 tables. v2: matches JCAP version. Added section to compare with Schmidt et al., 2018; added plot to show relative importance of different contributions to log-likelihoodSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Theory (hep-th)
- [65] arXiv:1909.07325 (replaced) [pdf, other]
-
Title: Magnetic topology in fluidsSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Plasma Physics (physics.plasm-ph)
- [66] arXiv:1909.07977 (replaced) [pdf, other]
-
Title: Multi-epoch X-ray burst modelling: MCMC with large grids of 1D simulationsComments: 15 pages, 10 figures, 3 tables. Updated Figs 3 and A1, minor corrections. Accepted by MNRASSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
- [67] arXiv:1910.06974 (replaced) [pdf, other]
-
Title: Not all stars form in clusters -- $Gaia$-DR2 uncovers the origin of OB associationsComments: 24 pages, 12 figures, accepted for publication in MNRASSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)
- [68] arXiv:1910.08021 (replaced) [pdf, ps, other]
-
Title: Enhanced mass-loss rate evolution of stars with $\gtrsim 18 M_\odot$ and missing optically-observed type II core-collapse supernovaeComments: Accepted for publication in MNRASSubjects: Solar and Stellar Astrophysics (astro-ph.SR); High Energy Astrophysical Phenomena (astro-ph.HE)
- [69] arXiv:1910.11448 (replaced) [pdf, other]
-
Title: Bayesian Approach for Determining Microlens System Properties with High-Angular-Resolution Follow-up ImagingComments: 71 pages, 17 figures, 7 tables, Accepted for publication in AJSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
- [70] arXiv:1910.11935 (replaced) [pdf, other]
-
Title: Fast acceleration of transrelativistic electrons in astrophysical turbulenceComments: Accepted for publication in The Astrophysical JournalSubjects: Plasma Physics (physics.plasm-ph); High Energy Astrophysical Phenomena (astro-ph.HE); Space Physics (physics.space-ph)
- [71] arXiv:1912.00057 (replaced) [pdf, other]
-
Title: The Evolution of Gamma-ray Burst Jet Opening Angle through Cosmic TimeAuthors: Nicole Lloyd-Ronning, Valeria U. Hurtado, Aycin Aykutalp, Jarrett Johnson, Chiara CeccobelloSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [72] arXiv:1912.03302 (replaced) [pdf, other]
-
Title: Milky Way Satellite Census. I. The Observational Selection Function for Milky Way Satellites in DES Y3 and Pan-STARRS DR1Authors: A. Drlica-Wagner, K. Bechtol, S. Mau, M. McNanna, E. O. Nadler, A. B. Pace, T. S. Li, A. Pieres, E. Rozo, J. D. Simon, A. R. Walker, R. H. Wechsler, T. M. C. Abbott, S. Allam, J. Annis, E. Bertin, D. Brooks, D. L. Burke, A. Carnero Rosell, M. Carrasco Kind, J. Carretero, M. Costanzi, L. N. da Costa, J. De Vicente, S. Desai, H. T. Diehl, P. Doel, T. F. Eifler, S. Everett, B. Flaugher, J. Frieman, J. Garcia-Bellido, E. Gaztanaga, D. Gruen, R. A. Gruendl, J. Gschwend, G. Gutierrez, K. Honscheid, D. J. James, E. Krause, K. Kuehn, N. Kuropatkin, O. Lahav, M. A. G. Maia, J. L. Marshall, P. Melchior, F. Menanteau, R. Miquel, A. Palmese, A. A. Plazas, E. Sanchez, V. Scarpine, M. Schubnell, S. Serrano, I. Sevilla-Noarbe, M. Smith, E. Suchyta, G. Tarle (DES Collaboration)Comments: 34 pages, 11 figures, 6 tables; updated to match published version. Selection functions available at: this https URLJournal-ref: ApJ 893, 1 (2020)Subjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [73] arXiv:1912.03303 (replaced) [pdf, other]
-
Title: Milky Way Satellite Census. II. Galaxy--Halo Connection Constraints Including the Impact of the Large Magellanic CloudAuthors: E. O. Nadler, R. H. Wechsler, K. Bechtol, Y. -Y. Mao, G. Green, A. Drlica-Wagner, M. McNanna, S. Mau, A. B. Pace, J. D. Simon, A. Kravtsov, S. Dodelson, T. S. Li, A. H. Riley, M. Y. Wang, T. M. C. Abbott, M. Aguena, S. Allam, J. Annis, S. Avila, G. M. Bernstein, E. Bertin, D. Brooks, D. L. Burke, A. Carnero Rosell, M. Carrasco Kind, J. Carretero, M. Costanzi, L. N. da Costa, J. De Vicente, S. Desai, A. E. Evrard, B. Flaugher, P. Fosalba, J. Frieman, J. García-Bellido, E. Gaztanaga, D. W. Gerdes, D. Gruen, J. Gschwend, G. Gutierrez, W. G. Hartley, S. R. Hinton, K. Honscheid, E. Krause, K. Kuehn, N. Kuropatkin, O. Lahav, M. A. G. Maia, J. L. Marshall, F. Menanteau, R. Miquel, A. Palmese, F. Paz-Chinchón, A. A. Plazas, E. Sanchez, B. Santiago, V. Scarpine, S. Serrano, M. Smith, M. Soares-Santos, et al. (5 additional authors not shown)Comments: 26 pages, 10 figures, 3 tables. Updated to published versionJournal-ref: ApJ 893, 1 (2020)Subjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [74] arXiv:1912.05296 (replaced) [pdf, ps, other]
-
Title: Search for dark matter towards the Galactic Centre with 11 years of ANTARES dataAuthors: The ANTARES CollaborationSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
- [75] arXiv:1912.05399 (replaced) [pdf, other]
-
Title: The exponential tail of inflationary fluctuations: consequences for primordial black holesComments: 34 pages, 14 figures. Matches JCAP version (added Fig. 14)Journal-ref: JCAP 03 (2020) 029Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Theory (hep-th)
- [76] arXiv:1912.06210 (replaced) [pdf, other]
-
Title: Hierarchical Bayesian Thermonuclear Rate for the $^7$Be(n,p)$^7$Li Big Bang Nucleosynthesis ReactionComments: 24 pages, 8 figures, ApJ in pressSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Instrumentation and Methods for Astrophysics (astro-ph.IM); Nuclear Theory (nucl-th)
- [77] arXiv:1912.11031 (replaced) [pdf, other]
-
Title: Constraining the dense matter equation of state with joint analysis of NICER and LIGO/Virgo measurementsAuthors: G. Raaijmakers, S. K. Greif, T. E. Riley, T. Hinderer, K. Hebeler, A. Schwenk, A. L. Watts, S. Nissanke, S. Guillot, J. M. Lattimer, R. M. LudlamComments: 18 pages, 8 figures. Accepted for publication in ApJ LettersJournal-ref: The Astrophysical Journal Letters, 893, L21 (2020)Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
- [78] arXiv:2001.01338 (replaced) [pdf, other]
-
Title: Detectability of Molecular Signatures on TRAPPIST-1e through Transmission Spectroscopy Simulated for Future Space-Based ObservatoriesAuthors: Daria Pidhorodetska, Thomas Fauchez, Geronimo Villanueva, Shawn Domagal-Goldman, Ravi Kumar KopparapuComments: Submitted to ApJLSubjects: Earth and Planetary Astrophysics (astro-ph.EP)
- [79] arXiv:2001.05024 (replaced) [pdf, other]
-
Title: A universal framework for t-channel dark matter modelsComments: 20 pages, 10 figures, version accepted by EPJCSubjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Experiment (hep-ex)
- [80] arXiv:2002.01185 (replaced) [pdf, other]
-
Title: Combined search for anisotropic birefringence in the gravitational-wave transient catalog GWTC-1Authors: Lijing ShaoComments: 13 pages, 6 figures, 6 tables; accepted by PRDSubjects: High Energy Physics - Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc)
- [81] arXiv:2002.01611 (replaced) [pdf, other]
-
Title: Survey of Gravitationally-lensed Objects in HSC Imaging (SuGOHI). V. Group-to-cluster scale lens search from the HSC-SSP SurveyAuthors: Anton T. Jaelani, Anupreeta More, Masamune Oguri, Alessandro Sonnenfeld, Sherry H. Suyu, Cristian E. Rusu, Kenneth C. Wong, James H. H. Chan, Issha Kayo, Chien-Hsiu Lee, Dani C. -Y. Chao, Jean Coupon, Kaiki T. Inoue, Toshifumi FutamaseComments: Accepted for publication in MNRAS, 19 pages, 11 figuresSubjects: Astrophysics of Galaxies (astro-ph.GA)
- [82] arXiv:2004.02921 (replaced) [pdf, other]
-
Title: Dark matter and Standard Model reheating from conformal GUT inflationComments: 38 pages, 9 figures, typos fixed, new appendix B added, references addedSubjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Theory (hep-th)
- [83] arXiv:2004.03601 (replaced) [pdf, other]
-
Title: Updated Parameters and a New Transmission Spectrum of HD 97658bAuthors: Xueying Guo, Ian J. M. Crossfield, Diana Dragomir, Molly R. Kosiarek, Joshua Lothringer, Thomas Mikal-Evans, Lee Rosenthal, Bjorn Benneke, Heather A. Knutson, Paul A. Dalba, Eliza M. R. Kempton, Gregory W. Henry, P. R. McCullough, Travis Barman, Sarah Blunt, Ashley Chontos, Jonathan Fortney, Benjamin J. Fulton, Lea Hirsch, Andrew W. Howard, Howard Isaacson, Jaymie Matthews, Teo Mocnik, Caroline Morley, Erik A. Petigura, Lauren M. WeissComments: Accepted to AJ. 29 pages, 21 figures, 11 tables, 2 machine-readable tables (system RVs and TSM values). v2: updated typosSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
- [84] arXiv:2004.03931 (replaced) [pdf, other]
-
Title: Global Mapping of the Surface Composition on an Exo-Earth using Color VariabilityAuthors: Hajime KawaharaComments: 20 pages, 14 figures, accepted for publication in ApJ. The code is available online at this https URL updated to match the published versionSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM)
- [85] arXiv:2004.07092 (replaced) [pdf, other]
-
Title: SDSS J211852.96-073227.5: The first non-local, interacting, late-type intermediate Seyfert galaxy with relativistic jetsAuthors: Emilia Järvelä, Marco Berton, Stefano Ciroi, Enrico Congiu, Anne Lähteenmäki, Francesco Di MilleComments: 7 pages, 6 figures, accepted for publication in A&ASubjects: Astrophysics of Galaxies (astro-ph.GA)
[ showing up to 2000 entries per page: fewer | more ]
Disable MathJax (What is MathJax?)
Links to: arXiv, form interface, find, astro-ph, recent, 2004, contact, help (Access key information)