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New submissions for Thu, 9 Jan 20
- [1] arXiv:2001.02230 [pdf, other]
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Title: The stellar-to-halo mass relation over the last 12 GyrAuthors: Giacomo Girelli, Lucia Pozzetti, Micol Bolzonella, Carlo Giocoli, Federico Marulli, Marco BaldiComments: accepted for publication in A&ASubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA)
Understanding how galaxy properties are linked to the dark matter halos they reside in, and how they co-evolve is a powerful tool to constrain the processes related to galaxy formation. The stellar-to-halo mass relation (SHMR) and its evolution over the history of the Universe provides insights on galaxy formation models and allows to assign galaxy masses to halos in N-body dark matter simulations. We use a statistical approach to link the observed galaxy stellar mass functions on the COSMOS field to dark matter halo mass functions from the DUSTGRAIN simulation and from a theoretical parametrization from z=0 to z=4. We also propose an empirical model to describe the evolution of the stellar-to-halo mass relation as a function of redshift. We calculate the star-formation efficiency (SFE) of galaxies and compare results with previous works and semi-analytical models.
- [2] arXiv:2001.02231 [pdf, other]
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Title: On the eccentricity evolution of massive black hole binaries in stellar backgroundsAuthors: Matteo Bonetti, Alexander Rasskazov, Alberto Sesana, Massimo Dotti, Francesco Haardt, Nathan W. C. Leigh, Manuel Arca Sedda, Giacomo Fragione, Elena RossiComments: 6 pages, 5 figures; submitted to MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE)
We study the dynamical evolution of eccentric massive black hole binaries (MBHBs) interacting with unbound stars by means of an extensive set of three body scattering experiments. Compared to previous studies, we extend the investigation down to a MBHB mass ratio of $q=m_2/m_1=10^{-4}$, where $m_1$ and $m_2$ are the masses of the primary and secondary hole respectively. Contrary to a simple extrapolation from higher mass ratios, we find that for $q\lesssim 10^{-3}$ the eccentricity growth rate becomes negative, i.e., the binary {\it circularise} as it shrinks. This behaviour is due to the subset of interacting stars captured in metastable counter-rotating orbits; those stars tend to extract angular momentum from the binary, promoting eccentricity growth for $q>10^{-3}$, but tend to inject angular momentum into the binary driving it towards circularisation for $q<10^{-3}$. The physical origin of this behaviour requires a detailed study of the orbits of this subset of stars and is currently under investigation. Our findings might have important consequences for intermediate MBHs (IMBHs) inspiralling onto MBHs (e.g. a putative $10^3\rm M_{\odot}$ black hole inspiralling onto SgrA$^*$).
- [3] arXiv:2001.02232 [pdf, ps, other]
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Title: On the accuracy of time-delay cosmography in the Frontier Fields Cluster MACS J1149.5+2223 with supernova RefsdalComments: 10 pages, 8 figures, 1 table; submitted to ApJ on the 18th of December 2019Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
We study possible systematic effects on the values of the cosmological parameters measured through strong lensing analyses of the HFF galaxy cluster MACS J1149.5+2223. We use the observed positions of a large set of spectroscopically selected multiple images, including those of supernova "Refsdal" with their estimated time delays. Starting from our reference model in a flat $\Lambda$CDM cosmology, published in Grillo et al. (2018), we confirm the relevance of the longest measurable time delay, between SX and S1, and an approximately linear relation between its value and that of $H_{0}$. We perform true blind tests by considering a range of time delays around its original estimate of $345 \pm 10$ days, as an accurate measurement of this time delay was not known at the time of analysis and writing. We investigate separately the impact of a constant sheet of mass at the cluster redshift, of a power-law profile for the mass density of the cluster main halo and of some scatter in the cluster member scaling relations. Remarkably, we find that these systematic effects do not introduce a significant bias on the inferred values of $H_{0}$ and $\Omega_{\rm m}$ and that the statistical uncertainties dominate the total error budget: a 3% uncertainty on the time delay of image SX translates into approximately 6% and 40% (including both statistical and systematic $1\sigma$) uncertainties for $H_{0}$ and $\Omega_{\rm m}$, respectively. Furthermore, our model accurately reproduces the extended surface brightness distribution of the supernova host, covering more than $3 \times 10^{4}$ $HST$ pixels. We also present the interesting possibility of measuring the value of the equation-of-state parameter $w$ of the dark energy density, currently with a 30% uncertainty. We conclude that time-delay cluster lenses have the potential to become soon an alternative and competitive cosmological probe.
- [4] arXiv:2001.02233 [pdf, other]
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Title: Cosmic Reionization On Computers: The Galaxy-Halo Connection between $5 \leq z \leq10$Comments: 10 pages, 8 figures, comments are welcomeSubjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
We explore the connection between the stellar component of galaxies and their host halos during the epoch of reionization ($5 \leq z\leq10$) using the CROC (Cosmic Reionization on Computers) simulations. We compare simulated galaxies with observations and find that CROC underpredicts the abundance of luminous galaxies when compared to observed UV luminosity functions, and analogously the most massive galaxies when compared to observed stellar mass functions. We can trace the deficit of star formation to high redshifts, where the slope of the star formation rate to stellar mass relation is consistent with observations, but the normalization is systematically low. This results in a star formation rate density and stellar mass density that is systematically offset from observations. However, the less luminous or lower stellar mass objects have luminosities and stellar masses that agree fairly well with observational data. We explore the stellar-to-halo mass ratio, a key quantity that is difficult to measure at high redshifts and that models do not consistently predict. In CROC, the stellar-to-halo mass ratio {\it decreases} with redshift, a trend opposite to some abundance matching studies. These discrepancies uncover where future effort should be focused in order to improve the fidelity of modeling cosmic reionization. We also compare the CROC galaxy bias with observational measurements using Lyman-Break Galaxy (LBG) samples. The good agreement of simulation and data shows that the clustering of dark matter halos is properly captured in CROC.
- [5] arXiv:2001.02234 [pdf, other]
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Title: Difficulties in Mid-Infrared selection of AGN in dwarf galaxiesComments: 7 pages, 7 figures, 1 table, accepted for publication on MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE)
While massive black holes (MBHs) are known to inhabit all massive galaxies, their ubiquitous presence in dwarf galaxies has not been confirmed yet, with only a limited number of sources detected so far. Recently, some studies proposed infrared emission as an alternative way to identify MBHs in dwarfs, based on a similar approach usually applied to quasars. In this study, by accurately combining optical and infrared data taking into account resolution effects and source overlapping, we investigate in detail the possible limitations of this approach with current ground-based facilities, finding a quite low ($\sim$0.4 per cent) fraction of active MBH in dwarfs that are luminous in mid-infrared, consistent with several previous results. Our results suggest that the infrared selection is strongly affected by several limitations that make the identification of MBHs in dwarf galaxies currently prohibitive, especially because of the very poor resolution compared to optical surveys, and the likely contamination by nearby sources, although we find a few good candidates worth further follow-ups. Optical, X-ray and radio observations, therefore, still represent the most secure way to search for MBH in dwarfs.
- [6] arXiv:2001.02235 [pdf, other]
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Title: Transfer of Life by Earth-Grazing Objects to Exoplanetary SystemsComments: 4 pages, 2 figures; submitted for publicationSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Astrophysics of Galaxies (astro-ph.GA)
Recently, a 30 cm object was discovered to graze the Earth's atmosphere and shift into a Jupiter-crossing orbit. We use the related survey parameters to calibrate the total number of such objects. The number of objects that could have exported terrestrial microbes out of the Solar System is in the range $2 \times 10^{9} - 3 \times 10^{11}$. We find that $10^{7} - 10^{9}$ such objects could have been captured by binary star systems over the lifetime of the Solar System. The total number of objects carrying living microbes on them upon capture is $10 - 10^3$.
- [7] arXiv:2001.02236 [pdf, other]
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Title: On the origin of pulsar radio emissionComments: 9 pages, 4 figuresSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
Since pulsars were discovered as emitters of bright coherent radio emission more than half a century ago, the cause of the emission has remained a mystery. In this Letter we demonstrate that coherent radiation can be directly generated in non-stationary pair plasma discharges which are responsible for filling the pulsar magnetosphere with plasma. By means of large-scale two-dimensional kinetic plasma simulations, we show that if pair creation is non-uniform across magnetic field lines, the screening of electric field by freshly produced pair plasma is accompanied by the emission of waves which are electromagnetic in nature. Using localized simulations of the screening process, we identify these waves as superluminal ordinary (O-) modes, which should freely escape from the magnetosphere as the plasma density drops along the wave path. The spectrum of the waves is broadband and the frequency range is comparable to that of observed pulsar radio emission.
- [8] arXiv:2001.02237 [pdf, other]
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Title: Kinematics of Simulated Galaxies II: Probing the Stellar Kinematics of Galaxies out to Large RadiiAuthors: Felix Schulze, Rhea-Silvia Remus, Klaus Dolag, Sabine Bellstedt, Andreas Burkert, Duncan A. ForbesSubjects: Astrophysics of Galaxies (astro-ph.GA)
We investigate the stellar kinematics of a sample of galaxies extracted from the hydrodynamic cosmological Magneticum Pathfinder simulations out to $5$ half-mass radii. We construct differential radial stellar spin profiles quantified by the observationally widely used $\lambda_\mathrm{R}$ and the closely related $(V/\sigma)$ parameters. We find three characteristic profile shapes: profiles exhibiting a (i) peak within $2.5$ half-mass radii and a subsequent decrease (ii) continuous increase that plateaus at larger radii typically with a high amplitude (iii) completely flat behaviour typically with low amplitude, in agreement with observations. This shows that the kinematic state of the stellar component can vary significantly with radius, suggesting a distinct interplay between in-situ star formation and ex-situ accretion of stars. Following the evolution of our sample through time, we provide evidence that the accretion history of galaxies with decreasing profiles is dominated by the anisotropic accretion of low mass satellites that get disrupted beyond $ \sim 2.0$ half-mass radii, building up a stellar halo with non-ordered motion while maintaining the central rotation already present at $z=2$. In fact, at $z=2$ decreasing profiles are the predominant profile class. Hence, we can predict a distinct formation pathway for galaxies with a decreasing profile and show that the centre resembles an old embedded disk. Furthermore, we show that the radius of the kinematic transition provides a good estimation for the transition radius from in-situ stars in the centre to accreted stars in the halo.
- [9] arXiv:2001.02239 [pdf, other]
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Title: Afterglow Lightcurves from Misaligned Structured JetsComments: 14 pages, 17 figuresSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
GRB 170817A / GW170817 is the first GRB that was clearly viewed from a line of sight far from the GRB jet's symmetry axis, well outside of its narrow core. It has been modeled extensively, primarily numerically, and although this endeavour was very fruitful, many of the underlying model parameters still remain undetermined. We provide here detailed analytic modelling of GRB afterglows observed off-axis, considering jets with a narrow core (of half-opening angle $\theta_{\rm c}$) and power-law wings in energy per unit solid angle ($\epsilon=\epsilon_c\Theta^{-a}$ where $\Theta=[1+(\theta/\theta_{\rm c})^2]^{1/2}$) and initial specific kinetic energy ($\Gamma_0-1=[\Gamma_{\rm c,0}-1]\Theta^{-b}$), as well as briefly discuss Gaussian jets. Our study reveals qualitatively different types of lightcurves that can be viewed in future off-axis GRBs, with either single or double peaks, depending on the jet structure and the viewing angle. Considering the lightcurve shape rather than the absolute normalizations of times and / or fluxes, removes the dependence of the lightcurve on many of the highly degenerate burst parameters and allows for robust estimates of several key parameters. Such a study is complimentary to numerical modelling and can be easily used to determine the underlying jet structure, significantly reduce the effective parameter space for numerical fitting attempts and provide physical insights. As an illustration, we show that for GRB 170817A, there is a strong correlation between the allowed values of $\Gamma_{\rm c,0}$ and $b$, leading to a narrow strip of allowed solutions in the $\Gamma_{\rm c,0}$-$b$ plane above some minimal values $\Gamma_{\rm c,0}\gtrsim 40, b\gtrsim1.2$. Furthermore, the Lorentz factor of the material dominating the early lightcurve can be constrained by three independent techniques to be $\Gamma_{0}(\theta_{\rm min,0})\approx5-7$.
- [10] arXiv:2001.02240 [pdf, other]
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Title: On the Secondary Origin of Cosmic Ray PositronsComments: 6 pages, 2 figures, submitted to PRLSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
We investigate the possibility of secondary production as the source of cosmic ray (CR) positrons, taking into account observed electron and antiproton spectra and allowing that the reported steepening in the AMS-02 positron spectrum may be due to radiative losses. Using a simple argument based on the antiproton spectrum, we show that positrons cannot be purely secondary. Namely, the antiproton to positron ratio requires that positrons be uncooled up to a few hundred GeV. This requirement implies that CR protons escape from the Galaxy too quickly to reproduce the observed antiproton flux. We further show that this result rules out also more complex secondary production scenarios such as reacceleration and the Nested Leaky Box. Thus, we conclude that while antiprotons can be produced exclusively in secondary interactions, a primary source of CR positrons ---be it dark matter or pulsars--- is required to explain their spectrum.
- [11] arXiv:2001.02241 [pdf, other]
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Title: Metal-poor nuclear star clusters in two dwarf galaxies near Centaurus A suggesting formation from the in-spiraling of globular clustersAuthors: Katja Fahrion, Oliver Müller, Marina Rejkuba, Michael Hilker, Mariya Lyubenova, Glenn van de Ven, Iskren Y. Georgiev, Federico Lelli, Marcel S. Pawlowski, Helmut JerjenComments: 13 pages, 8 figures, accepted for publication by A&ASubjects: Astrophysics of Galaxies (astro-ph.GA)
Studies of nucleated dwarf galaxies can constrain the scenarios for the formation and evolution of nuclear star clusters (NSC) in low-mass galaxies and give us insights on the origin of ultra compact dwarf galaxies (UCDs). We report the discovery of a NSC in the dwarf galaxy KKs58 and investigate its properties together with those of another NSC in KK197. Both NSCs are hosted by dwarf elliptical galaxies of the Centaurus group. Combining ESO VLT MUSE data with photometry from VLT FORS2, CTIO Blanco DECam, and HST ACS, as well as high-resolution spectroscopy from VLT UVES, we analyse the photometric, kinematic and stellar population properties of the NSCs and their host galaxies. We confirm membership of the NSCs based on their radial velocities and location close to the galaxy centres. We also confirm the membership of two globular clusters (GCs) and detect oblate rotation in the main body of KK197. Based on high signal-to-noise spectra taken with MUSE of the NSCs of both KKs58 and KK197 we measure low metallicities, [Fe/H] = $-1.75 \pm 0.06$ dex and [Fe/H] = $-1.84 \pm 0.05$ dex, and stellar masses of $7.3 \times 10^5 M_\odot$ and $1.0 \times 10^6 M_\odot$, respectively. Both NSCs are more metal-poor than their hosts that have metallicities of $-1.35 \pm 0.23$ dex (KKs58) and $-0.84 \pm 0.12$ dex (KK197). This can be interpreted as NSC formation via the in-spiral of GCs. The masses, sizes and metallicities of the two NSCs place them among other NSCs, but also among the known UCDs of the Centaurus group. This indicates that NSCs might constitute the progenitors of a part of the low-mass UCDs, although their properties are almost indistinguishable from typical GCs.
- [12] arXiv:2001.02242 [pdf, other]
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Title: KASHz: No evidence for ionised outflows instantaneously suppressing star formation in moderate luminosity AGN at $z$$\sim$$1.4$-$2.6$Authors: J. Scholtz, C.M. Harrison, D.J. Rosario, D.M. Alexander, C-C. Chen, D. Kakkad, V. Mainieri, A.L. Tiley, O. Turner, M. Cirasuolo, R.M. Sharples, S. StachComments: Accepted for publication by MNRAS, 24 pages, 12 FiguresSubjects: Astrophysics of Galaxies (astro-ph.GA)
As part of our KMOS AGN Survey at High-redshift (KASHz), we present spatially-resolved VLT/KMOS and VLT/SINFONI spectroscopic data and ALMA 870$\mu$m continuum imaging of eight $z$=1.4--2.6 moderate AGN ($L_{\rm 2-10 \rm kev}$ = $10^{42} - 10^{45}$ ergs s$^{-1}$). We map [OIII], H$\alpha$ and rest-frame FIR emission to search for any spatial anti-correlation between ionised outflows (traced by the [OIII] line) and star formation (SF; traced by H$\alpha$ and FIR), that has previously been claimed for some high-z AGN and used as evidence for negative and/or positive AGN feedback. Firstly, we conclude that H$\alpha$ is unreliable to map SF inside our AGN host galaxies based on: (i) SF rates inferred from attenuation-corrected H$\alpha$ can lie below those inferred from FIR; (ii) the FIR continuum is more compact than the H$\alpha$ emission by a factor of $\sim 2$ on average; (iii) in half of our sample, we observe significant spatial offsets between the FIR and H$\alpha$ emission, with an average offset of $1.4\pm0.6$ kpc. Secondly, for the five targets with outflows we find no evidence for a spatial anti-correlation between outflows and SF using either H$\alpha$ or FIR as a tracer. This holds for our re-analysis of a famous $z$=1.6 X-ray AGN (`XID 2028') where positive and negative feedback has been previously claimed. Based on our results, any impact on SF by ionised outflows must be subtle, either occurring on scales below our resolution, or on long timescales.
- [13] arXiv:2001.02243 [pdf, other]
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Title: A \emph{Gaia}-based catalog of candidate stripped nuclei and luminous globular clusters in the halo of Centaurus\,AAuthors: Karina T. Voggel, Anil C. Seth, David J. Sand, Allison Hughes, Jay Strader, Denija Crnojevic, Nelson CaldwellComments: Accepted to ApJSubjects: Astrophysics of Galaxies (astro-ph.GA)
Tidally stripped galaxy nuclei and luminous globular clusters (GCs) are important tracers of the halos and assembly histories of nearby galaxies, but are difficult to reliably identify with typical ground-based imaging data. In this paper we present a new method to find these massive star clusters using \emph{Gaia} DR2, focusing on the massive elliptical galaxy Centaurus\,A (Cen\,A). We show that stripped nuclei and globular clusters are partially resolved by \emph{Gaia} at the distance of Cen\,A, showing characteristic astrometric and photometric signatures. We use this selection method to produce a list of 632 new candidate luminous clusters in the halo of Cen\,A out to a projected radius of 150 kpc. Adding in broadband photometry and visual examination improves the accuracy of our classification. In a spectroscopic pilot program we have confirmed 5 new luminous clusters, which includes the 7th and 10th most luminous GC in Cen\,A. Three of the newly discovered GCs are further away from Cen\,A in than all previously known GCs. Several of these are compelling candidates for stripped nuclei. We show that our novel \emph{Gaia} selection method retains at least partial utility out to distances of $\sim 25$ Mpc and hence is a powerful tool for finding and studying star clusters in the sparse outskirts of galaxies in the local universe.
- [14] arXiv:2001.02253 [pdf, other]
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Title: X-ray Observations of the Peculiar Cepheid V473 Lyr Identify A Low-Mass CompanionAuthors: Nancy Remage Evans (1), Ignazio Pillitteri (2), Laszlo Molnar (3), Laszlo Szabados (3), Emese Plachy (3), Robert Szabo (3), Scott Engle (4), Ed Guinan (4), Scott Wolk (1), H. Moritz Guenther (5), Hilding Neilson (6), Massimo Marengo (7), Lynn D. Matthews (8), Sofia Moschou (1), Jeremy J. Drake (1), Vinay Kashyap (1), Pierre Kervella (9), Tamas Tordai (10), Peter Somogyi (11), Gilbert Burki (12) ((1) Harvard Smithsonian Center for Astrophysics, (2) INAF-Osservatorio di Palermo, (3) Konkoly Observatory, (4) Villanova University, (5) Massachusetts Institute of Technology, (6) University of Toronto, (7) Iowa State University, (8) Massachusetts Institute of Technology, Haystack Observatory, (9) Observatoire de Paris, (10) Polaris Observatory, Hungarian Astronomical Association, (11) Zrinyi u. 23., 2890, Tata, Hungary, (12) Observatoire de Geneve)Comments: Accepted by AJSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
V473 Lyr is a classical Cepheid which is unique in having substantial amplitude variations with a period of approximately 3.3 years, thought to be similar to the Blazhko variations in RR Lyrae stars. We obtained an {\it XMM-Newton} observation of this star to followup a previous detection in X-rays. Rather than the X-ray burst and rapid decline near maximum radius seen in $\delta$ Cephei itself, the X-ray flux in V473 Lyr remained constant for a third of the pulsation cycle covered by the observation. Thus the X-rays are most probably not produced by the changes around the pulsation cycle. The X-ray spectrum is soft (kT = 0.6 keV), with
X-ray properties which are consistent with a young low mass companion. Previously there was no evidence of a companion in radial velocities or in {\it Gaia} and {\it Hipparcos} proper motions. While this rules out companions which are very close or very distant, a binary companion at a separation between 30 and 300 AU is possible. This is an example of an X-ray observation revealing evidence of a low mass companion, which is important in completing the mass ratio statistics of binary Cepheids. Furthermore, the detection of a young X-ray bright companion is a further indication that the Cepheid (primary) is a Population I star, even though its pulsation behavior differs from other classical Cepheids. - [15] arXiv:2001.02259 [pdf, other]
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Title: Differential Emission Measure Plasma Diagnostics of a Long-Lived Coronal HoleAuthors: Jonas Saqri, Astrid M. Veronig, Stephan G. Heinemann, Stefan J. Hofmeister, Manuela Temmer, Karin Dissauer, Yang SuComments: Accepted for publication in Solar PhysicsSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
We use Solar Dynamics Observatory (SDO)/Atmospheric Imaging Assembly (AIA) data to reconstruct the plasma properties from differential emission measure (DEM) analysis for a previously studied long-lived, low-latitude coronal hole (CH) over its lifetime of ten solar rotations. We initially obtain a non-isothermal DEM distribution with a dominant component centered around 0.9 MK and a secondary smaller component at 1.5 - 2.0 MK. We find that deconvolving the data with the instrument point spread function (PSF) to account for long-range scattered light reduces the secondary hot component. Using the 2012 Venus transit and a 2013 lunar eclipse to test the efficiency of this deconvolution, significant amounts of residual stray light are found for the occulted areas. Accounting for this stray light in the error budget of the different AIA filters further reduces the secondary hot emission, yielding CH DEM distributions that are close to isothermal with the main contribution centered around 0.9 MK. Based on these DEMs, we analyze the evolution of the emission measure (EM), density, and averaged temperature during the CH's lifetime. We find that once the CH is clearly observed in EUV images, the bulk of the CH plasma reveals a quite constant state, i.e. temperature and density reveal no major changes, whereas the total CH area and the photospheric magnetic fine structure inside the CH show a distinct evolutionary pattern. These findings suggest that CH plasma properties are mostly "set" at the CH formation or/and that all CHs have similar plasma properties.
- [16] arXiv:2001.02283 [pdf, other]
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Title: Stellar Property Statistics of Massive Halos from Cosmological Hydrodynamics Simulations: Common Kernel ShapesAuthors: Dhayaa Anbajagane, August E. Evrard, Arya Farahi, David J. Barnes, Klaus Dolag, Ian G. McCarthy, Dylan Nelson, Annalisa PillepichComments: 17 pages, 15 figuresSubjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
We study stellar property statistics, including satellite galaxy occupation, of massive halo populations realized by three cosmological hydrodynamics simulations: BAHAMAS + MACSIS, TNG300 of the IllustrisTNG suite, and Magneticum Pathfinder. The simulations incorporate independent sub-grid methods for astrophysical processes with spatial resolutions ranging from $1.5$ to $6$ kpc, and each generates samples of $1000$ or more halos with $M_{\rm halo}> 10^{13.5} M_{\odot}$ at redshift $z=0$. Applying localized, linear regression (LLR), we extract halo mass-conditioned statistics (normalizations, slopes, and intrinsic covariance) for a three-element stellar property vector consisting of: i) $N_{sat}$, the number of satellite galaxies with stellar mass, $M_{\star, \rm sat} > 10^{10} M_{\odot}$ within radius $R_{200c}$ of the halo; ii) $M_{\star,\rm tot}$, the total stellar mass within that radius, and; iii) $M_{\star,\rm BCG}$, the gravitationally-bound stellar mass of the central galaxy within a $100 \, \rm kpc$ radius. Scaling parameters for the three properties with halo mass show mild differences among the simulations, in part due to numerical resolution, but there is qualitative agreement on property correlations, with halos having smaller than average central galaxies tending to also have smaller total stellar mass and a larger number of satellite galaxies. Marginalizing over total halo mass, we find the satellite galaxy kernel, $p(\ln N_{sat}\,|\,M_{\rm halo},z)$ to be consistently skewed left, with skewness parameter $\gamma = -0.91 \pm 0.02$, while that of $\ln M_{\star,\rm tot}$ is closer to log-normal, in all three simulations. The highest resolution simulations find $\gamma \simeq -0.8$ for the $z=0$ shape of $p(\ln M_{\star,\rm BCG}\,|\,M_{\rm halo},z)$ and also that the fractional scatter in total stellar mass is below $10\%$ in halos more massive than $10^{14.3} M_{\odot}$.
- [17] arXiv:2001.02341 [pdf, other]
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Title: Nucleosynthesis in early rotating massive stars and chemical composition of CEMP starsComments: Proceeding of the Nuclear Physics in Astrophysics IX conference, to appear in the Journal of Physics: Conference SeriesSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
The first massive stars triggered the onset of chemical evolution by releasing the first metals (elements heavier than helium) in the Universe. The nature of these stars and how the early chemical enrichment took place is still largely unknown. Rotational-induced mixing in the stellar interior can impact the nucleosynthesis during the stellar life of massive stars and lead to stellar ejecta having various chemical compositions. We present low and zero-metallicity 20, 25 and 40 $M_{\odot}$ stellar models with various initial rotation rates and assumptions for the nuclear reactions rates. With increasing initial rotation, the yields of light (from $\sim$ C to Al) and trans-iron elements are boosted. The trans-iron elements (especially elements heavier than Ba) are significantly affected by the nuclear reaction uncertainties. The chemical composition of the observed CEMP (carbon-enhanced metal-poor) stars CS29528-028 and HE0336+0113 are consistent with the chemical composition of the material ejected by a fast rotating 40~$M_{\odot}$ model.
- [18] arXiv:2001.02358 [pdf, other]
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Title: Characterization of unresolved and unclassified sources detected in radio continuum surveys of the Galactic planeAuthors: Arnab Chakraborty, Nirupam Roy, Y.Wang, Abhirup Datta, H. Beuther, S.-N.X. Medina, K. M. Menten, J. S. Urquhart, A. Brunthaler, S. A. DzibComments: There are 6 pages and 3 figures. The paper is accepted for publication in MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
The continuum emission from 1 to 2 GHz of The HI/OH/Recombination line survey of the inner Milky Way (THOR) at $\lesssim$18" resolution covers $\sim 132$ square degrees of the Galactic plane and detects 10387 sources. Similarly, the first data release of the Global View of Star Formation in the Milky Way (GLOSTAR) surveys covers $\sim 16$ square degrees of the Galactic plane from 4-8 GHz at 18" resolution and detects 1575 sources. However, a large fraction of the unresolved discrete sources detected in these radio continuum surveys of the Galactic plane remain unclassified. Here, we study the Euclidean-normalized differential source counts of unclassified and unresolved sources detected in these surveys and compare them with simulated extragalactic radio source populations as well as previously established source counts. We find that the differential source counts for THOR and GLOSTAR surveys are in excellent agreement with both simulation and previous observations. We also estimate the angular two-point correlation function of unclassified and unresolved sources detected in THOR survey. We find a higher clustering amplitude in comparison with the Faint Images of the Radio Sky at Twenty-cm (FIRST) survey up to the angular separation of $5^{\circ}$. The decrease in angular correlation with increasing flux cut and the excellent agreement of clustering pattern of sources above 1 mJy with high $z$ samples ($z >0.5$) of the FIRST survey indicates that these sources might be high $z$ extragalactic compact objects. The similar pattern of one-point and two-point statistics of unclassified and compact sources with extragalactic surveys and simulations confirms the extragalactic origin of these sources.
- [19] arXiv:2001.02361 [pdf, other]
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Title: The Effects of Tilt on the Images of Black Hole Accretion FlowsComments: 14 pages, 14 figures, submitted to ApJSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
We analyze two 3D general-relativistic magnetohydrodynamic accretion simulations in the context of how they would manifest in Event Horizon Telescope (EHT) observations of supermassive black holes. The two simulations differ only in whether the initial angular momentum of the plasma is aligned with the rapid (a = 0.9) spin of the black hole. Both have low net magnetic flux. Ray tracing is employed to generate resolved images of the synchrotron emission. When using parameters appropriate for Sgr A* and assuming a viewing angle aligned with the black hole spin, we find the most prominent difference is that the central shadow in the image is noticeably eccentric in tilted models, with the ring of emission relatively unchanged. Applying this procedure to M87 with a viewing angle based on the large-scale jet, we find that adding tilt increases the angular size of the ring for fixed black hole mass and distance, while at the same time increasing the number of bright spots in the image. Our findings illustrate observable features that can distinguish tilted from aligned flows. They also show that tilted models can be viable for M87, and that not accounting for tilt can bias inferences of physical parameters. Future modeling of horizon-scale observations should account for potential angular momentum misalignment, which is likely generic at the low accretion rates appropriate for EHT targets.
- [20] arXiv:2001.02365 [pdf, other]
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Title: Diffuse radio emission in the galaxy cluster SPT-CL J2031-4037: a steep spectrum intermediate radio halo?Authors: Ramij Raja, Majidul Rahaman, Abhirup Datta, Jack O. Burns, Huib T. Intema, R. J. van Weeren, Eric J. Hallman, David Rapetti, Surajit PaulComments: 6 pages, 3 figures; Accepted for publication in MNRAS LetterSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Astrophysics of Galaxies (astro-ph.GA)
The advent of sensitive low frequency radio observations has revealed a number of diffuse radio objects with peculiar properties that are challenging our understanding about the physics of the intracluster medium. Here, we report the discovery of a steep spectrum radio halo surrounding the central Brightest Cluster Galaxy (BCG) in the galaxy cluster SPT-CL J2031-4037. This cluster is morphologically disturbed yet has a weak cool core, an example of cool core/non-cool core transition system, which harbours a radio halo of $\sim 0.7$ Mpc in size. The halo emission detected at 1.7 GHz is less extended compared to that in the 325 MHz observation, and the spectral index of the part of the halo visible at 325 MHz to 1.7 GHz frequencies was found to be $-1.35 \pm 0.07$. Also, $P_{1.4\ \mathrm{GHz}}$ was found to be $0.77 \times 10^{24}$ W Hz$^{-1}$ which falls in the region where radio mini-halos, halo upper limits and ultra-steep spectrum (USS) halos are found in the $P_{1.4\ \mathrm{GHz}} - L_\mathrm{X}$ plane. Additionally, simulations presented in the paper provide support to the scenario of the steep spectrum. The diffuse radio emission found in this cluster may be a steep spectrum "intermediate" or "hybrid" radio halo which is transitioning into a mini-halo.
- [21] arXiv:2001.02367 [pdf]
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Title: Thaddäus Derfflinger's sunspot observations during 1802-1824: A primary reference to understand the Dalton MinimumAuthors: Hisashi Hayakawa, Bruno P. Besser, Tomoya Iju, Rainer Arlt, Shoma Uneme, Shinsuke Imada, Philippe-A. Bourdin, Amand KramlComments: main text 17 pages, references 7 pages, and 8 figures; accepted for publication in the ApJJournal-ref: The Astrophysical Journal, 2020Subjects: Solar and Stellar Astrophysics (astro-ph.SR)
As we are heading towards the next solar cycle, presumably with a relatively small amplitude, it is of significant interest to reconstruct and describe the past grand minima on the basis of actual observations of the time. The Dalton Minimum is often considered one of the grand minima captured in the coverage of telescopic observations. Nevertheless, the reconstructions of the sunspot group number vary significantly, and the existing butterfly diagrams have a large data gap during the period. This is partially because most long-term observations have remained unexplored in historical archives. Therefore, to improve our understanding on the Dalton Minimum, we have located two series of Thadd\"aus Derfflinger's observational records (a summary manuscript and logbooks) as well as his Brander's 5.5-feet azimuthal-quadrant preserved in the Kremsm\"unster Observatory. We have revised the existing Derfflinger's sunspot group number with Waldmeier classification and eliminated all the existing 'spotless days' to remove contaminations from solar meridian observations. We have reconstructed the butterfly diagram on the basis of his observations and illustrated sunspot distributions in both solar hemispheres. Our article aims to revise the trend of Derfflinger's sunspot group number and to bridge a data gap of the existing butterfly diagrams around the Dalton Minimum. Our results confirm that the Dalton Minimum is significantly different from the Maunder Minimum, both in terms of cycle amplitudes and sunspot distributions. Therefore, the Dalton Minimum is more likely a secular minimum in the long-term solar activity, while further investigations for the observations at that time are required.
- [22] arXiv:2001.02398 [pdf, other]
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Title: Optical Variability of the TeV Blazar 1ES 0806+524 on Diverse TimescalesAuthors: Ashwani Pandey, Alok C. Gupta, Sofia O. Kurtanidze, Paul J. Wiita, G. Damljanovic, R. Bachev, Jin Zhang, O. M. Kurtanidze, A. Darriba, R. A. Chigladze, G. Latev, M. G. Nikolashvili, S. Peneva, E. Semkov, A. Strigachev, S. N. Tiwari, O. VinceComments: 14 pages, 6 figures, 7 tables, accepted for publication in ApJSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
We report the results of our optical (VRI) photometric observations of the TeV blazar 1ES 0806$+$524 on 153 nights during 2011-2019 using seven optical telescopes in Europe and Asia. We investigated the variability of the blazar on intraday as well as on long-term timescales. We examined eighteen intraday light curves for flux and color variations using the most reliable power-enhanced F-test and the nested ANOVA test. Only on one night was a small, but significant, variation found, in both $V$ band and $R$ band light curves. The $V-R$ color index was constant on every one of those nights. Flux density changes of around 80 % were seen over the course of these eight years in multiple bands. We found a weighted mean optical spectral index of 0.639$\pm$0.002 during our monitoring period by fitting a power law ($F_{\nu} \propto \nu^{-\alpha}$) in 23 optical ($VRI$) spectral energy distributions of 1ES 0806$+$524. We discuss different possible mechanisms responsible for blazar variability on diverse timescales.
- [23] arXiv:2001.02413 [pdf, other]
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Title: The strange case of the peculiar spiral galaxy NGC5474. New pieces of a galactic puzzleAuthors: M. Bellazzini (INAF-OAS Bo), F. Annibali (INAF-OAS Bo), M. Tosi (INAF-OAS Bo), A. Mucciarelli (UniBo DIFA), M. Cignoni (UniPi DIF), G. Beccari (ESO -Garching), C. Nipoti (UniBo DIFA), R. Pascale (UniBo DIFA)Comments: Accepted for publication on Astronomy & Astrophysics. Latex, 10 pages, 12 figures (colors)Subjects: Astrophysics of Galaxies (astro-ph.GA)
We present the first analysis of the stellar content of the structures and substructures identified in the peculiar star-forming galaxy NGC5474, based on Hubble Space Telescope resolved photometry from the LEGUS survey. NGC5474 is a satellite of the giant spiral M101, and is known to have a prominent bulge that is significantly off-set from the kinematic center of the underlying HI and stellar disc. The youngest stars (age~ 100 Myr) trace a flocculent spiral pattern extending out to ~8 kpc from the center of the galaxy. On the other hand intermediate-age (age > 500 Myr) and old (age > 2 Gyr) stars dominate the off-centred bulge and a large substructure residing in the South Western part of the disc and not correlated with the spiral arms (SW over-density). The old age of the stars in the SW over-density suggests that this may be another signature of the dynamical interaction/s that have shaped this anomalous galaxy. We suggest that a fly by with M101, generally invoked as the origin of the anomalies, may not be sufficient to explain all the observations. A more local and more recent interaction may help to put all the pieces of this galactic puzzle together.
- [24] arXiv:2001.02420 [pdf, other]
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Title: The stellar and wind parameters of six prototypical HMXBs and their evolutionary statusAuthors: R. Hainich, L. M. Oskinova, J. M. Torrejón, F. Fuerst, A. Bodaghee, T. Shenar, A. A. C. Sander, H. Todt, K. Spetzer, W.-R. HamannComments: 44 pages, 13 figures, 15 tables; accepted for publication in A&ASubjects: Solar and Stellar Astrophysics (astro-ph.SR); High Energy Astrophysical Phenomena (astro-ph.HE)
High-mass X-ray binaries (HMXBs) are exceptional astrophysical laboratories that offer a rare glimpse into the physical processes that govern accretion on compact objects, massive-star winds, and stellar evolution. In a subset of the HMXBs, the compact objects accrete matter solely from winds of massive donor stars. These so-called wind-fed HMXBs are divided in persistent HMXBs and supergiant fast X-ray transients (SFXTs) according to their X-ray properties. While it has been suggested that this dichotomy depends on the characteristics of stellar winds, they have been poorly studied. With this investigation, we aim to remedy this situation by systematically analyzing donor stars of wind-fed HMXBs that are observable in the UV, concentrating on those with neutron star (NS) companions. We obtained Swift X-ray data, HST UV spectra, and additional optical spectra for all our targets. Our multi-wavelength approach allows us to provide stellar and wind parameters for six donor stars (four wind-fed systems and two OBe X-ray binaries). The wind properties are in line with the predictions of the line-driven wind theory. Three of the donor stars are in an advanced evolutionary stage, while for some of the stars, the abundance pattern indicates that processed material might have been accreted. When passing by the NS in its tight orbit, the donor star wind has not yet reached its terminal velocity but it is still significantly slower; its speed is comparable with the orbital velocity of the NS companion. There are no systematic differences between the two types of wind-fed HMXBs (persistent versus transients) with respect to the donor stars. For the SFXTs in our sample, the orbital eccentricity is decisive for their transient X-ray nature. Based on the orbital parameters and the further evolution of the donor stars, the investigated HMXBs will presumably form Thorne-\.Zytkow objects in the future.
- [25] arXiv:2001.02449 [pdf, other]
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Title: Studying the molecular gas towards a bright rimmed cloud at the infrared dust bubble N30Comments: Accepted to be published in BAAASubjects: Astrophysics of Galaxies (astro-ph.GA)
We present a study on the molecular gas towards a bright-rimmed cloud located to the north of the infrared dust bubble N30. Using the emission from the 12CO, 13CO, and C18O J=3-2 line, together with infrared and radio continuum data, we characterized the bubble and the related molecular cloud. In addition, we show an analysis of the behaviour of the abundance ratio 13CO/C18O towards the bright-rimmed cloud, and we search for clues on recent star-formation.
- [26] arXiv:2001.02451 [pdf, other]
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Title: Is the Hubble tension a hint of AdS around recombination?Comments: 6 pages, 5 figuresSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Theory (hep-th)
Anti-de Sitter (AdS) vacua, being theoretically important, might have unexpected impact on the observable universe. We find that in early dark energy (EDE) scenarios the existence of AdS vacua around recombination can effectively lift the CMB-inferred $H_0$ value. As an example, we study a phenomenological EDE model with an AdS phase starting at the redshift $z\sim2000$ and ending shortly after recombination (hereafter the universe will settle down in a $\Lambda>0$ phase till now), and obtain a best-fit $H_0=72.74$ km/s/Mpc without degrading the CMB fit compared with the standard $\Lambda$CDM model.
- [27] arXiv:2001.02458 [pdf, other]
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Title: Investigating Multiwavelength Lognormality with Simulations : Case of Mrk 421Authors: Nachiketa ChakrabortyComments: Accepted in GalaxiesSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Astrophysics of Galaxies (astro-ph.GA); Data Analysis, Statistics and Probability (physics.data-an)
Blazars are highly variable and display complex characteristics. A key characteristic is the flux probability distribution function or flux PDF whose shape depends upon the form of the underlying physical process driving variability. The BL Lacertae Mrk 421 is one of the brightest and most variable blazars across the electromagnetic spectrum. It has been reported to show hints of lognormality across the spectrum from radio to gamma-ray histograms of observed fluxes. This would imply that the underlying mechanisms may not conform to the "standard" additive, multi-zone picture, but could potentially have multiplicative processes. This is investigated by testing the observed lightcurves at different wavelengths with time-series simulations. We find that the simulations reveal a more complex scenario, than a single lognormal distribution explaining the multiwavelength lightcurves of Mrk 421.
- [28] arXiv:2001.02461 [pdf, other]
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Title: Real galaxy mergers from galaxy pair catalogsComments: submitted to MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA); Instrumentation and Methods for Astrophysics (astro-ph.IM)
Mergers of galaxies are extremely violent events shaping their evolution. Such events are thought to trigger starbursts and, possibly, black hole accretion. Nonetheless, it is still not clear how to know the fate of a galaxy pair from the data available at a given time, limiting our ability to constrain the exact role of mergers. In this paper we use the lightcone of the Horizon-AGN simulation, for which we know the fate of each pair, to test three selection processes aiming at identifying true merging pairs. We find that the simplest one (selecting objects within two thresholds on projected distance $d$ and redshift difference $\Delta z$) gives similar results than the most complex one (based on a neural network analyzing $d$, $\Delta z$, redshift of the primary, masses/star formation rates/aspect ratio of both galaxies). Our best thresholds are $d_\mathrm{th}\sim100\mathrm{\, kpc}$ and $\Delta z_\mathrm{th} \sim 10^{-3}$, in agreement with recent results.
- [29] arXiv:2001.02465 [pdf, other]
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Title: Galaxy And Mass Assembly (GAMA): Defining Passive Galaxy Samples and Searching for the UV UpturnAuthors: S. Phillipps (1), S.S. Ali (1,2), M.N. Bremer (1), R. De Propris (3), A.E. Sansom (4), M.E. Cluver (5,6), M. Alpaslan (7), S. Brough (8), M.J.I. Brown (9), L.J.M. Davies (10), S.P. Driver (10,11) . M.W. Grootes (12), B.W. Holwerda (13), A.M. Hopkins (14), P.A. James (15), K. Pimbblet (16), A.S.G. Robotham (10), E.N. Taylor (5), L. Wang (17,18) ((1) Astrophysics Group, School of Physics, University of Bristol, Tyndall Avenue, Bristol, UK (2) Subaru Telescope, NAOJ, Hilo, HI, USA (3) Finnish Centre for Astronomy with ESO, University of Turku, Turku, Finland (4) Jeremiah Horrocks Institute, School of Physical Sciences and Computing, University of Central Lancashire, UK (5) Centre for Astrophysics and Supercomputing, Swinburne University of Technology, Hawthorn, Australia (6) Department of Physics and Astronomy, University of the Western Cape, Belville, South Africa (7) Center for Cosmology and Particle Physics, Department of Physics, New York University, NY, USA (8) School of Physics, University of New South Wales, NSW, Australia (9) School of Physics and Astronomy, Monash University, Clayton, Victoria, Australia (10) ICRAR, University of Western Australia, Crawley, WA, Australia (11) SUPA, School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, UK (12) Netherlands eScience Center, Amsterdam, The Netherlands (13) Department of Physics and Astronomy, University of Louisville, Louisville KY, USA (14) Australian Astronomical Optics, Macquarie University, North Ryde, NSW, Australia (15) Astrophysics Research Institute, Liverpool John Moores University, IC2, Liverpool Science Park, Liverpool, UK (16) E.A. Milne Centre for Astrophysics, University of Hull, Cottingham Road, Kingston-upon-Hull, UK (17) SRON Netherlands Institute for Space Research, Groningen, The Netherlands (18) Kapteyn Astronomical Institute, University of Groningen, Groningen, The Netherlands)Comments: Accepted by MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA)
We use data from the GAMA and GALEX surveys to demonstrate that the UV upturn, an unexpected excess of ultraviolet flux from a hot stellar component, seen in the spectra of many early-type galaxies, arises from processes internal to individual galaxies with no measurable influence from the galaxies' larger environment. We first define a clean sample of passive galaxies without a significant contribution to their UV flux from low-level star formation. We confirm that galaxies with the optical colours of red sequence galaxies often have signs of residual star formation, which, without other information, would prevent a convincing demonstration of the presence of UV upturns. However, by including (NUV$-u$) and {\it WISE} (W2-W3) colours, and FUV data where it exists, we can convincingly constrain samples to be composed of non-star-forming objects. Using such a sample, we examine GALEX photometry of low redshift GAMA galaxies in a range of low-density environments, from groups to the general field, searching for UV upturns. We find a wide range of (NUV$-r$) colours, entirely consistent with the range seen -- and attributed to the UV upturn -- in low-redshift red sequence cluster galaxies. The range of colours is independent of group multiplicity or velocity dispersion, with isolated passive galaxies just as likely to have blue UV-to-optical colours, implying significant upturn components, as those in richer groups and in the previous data on clusters. This is supported by equivalent results for (FUV$-r$) colours which are clear indicators of upturn components.
- [30] arXiv:2001.02473 [pdf, other]
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Title: Global climate modeling of Saturn's atmosphere. Part III: Global statistical picture of zonostrophic turbulence in high-resolution 3D-turbulent simulationsSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Fluid Dynamics (physics.flu-dyn)
We conduct an in-depth analysis of statistical flow properties calculated from the reference high-resolution Saturn simulation obtained by global climate modelling in Part II. In the steady state of this reference simulation, strongly energetic, zonally dominated, large-scale structures emerge, which scale with the Rhines scale. Spectral analysis reveals a strong anisotropy in the kinetic energy spectra, consistent with the zonostrophic turbulent flow regime. By computing spectral energy and enstrophy fluxes we confirm the existence of a double cascade scenario related to 2D-turbulent theory. To diagnose the relevant 3D dynamical mechanisms in Saturn's turbulent atmosphere, we run a set of four simulations using an idealized version of our Global Climate Model devoid of radiative transfer, with a well-defined Taylor-Green forcing and over several rotation rates (4, 1, 0.5, and 0.25 times Saturn's rotation rate). This allows us to identify dynamics in three distinctive inertial ranges: (1) a ``residual-dominated'' range, in which non-axisymmetric structures dominate with a -5/3 spectral slope; (2) a ``zonostrophic inertial'' range, dominated by axisymmetric jets and characterized by the pile-up of strong zonal modes with a steeper, nearly -3, spectral slope; and (3) a ``large-scale'' range, beyond Rhines' typical length scale, in which the reference Saturn simulation and our idealized simulations differ. In the latter range, the dynamics is dominated by long-lived zonal modes 2 and 3 when a Saturn-like seasonal forcing is considered (reference simulation), and a steep energetic decrease with the idealized Taylor-Green forcing. Finally, instantaneous spectral fluxes show the coexistence of upscale and downscale enstrophy/energy transfers at large scales, specific to the regime of zonostrophic turbulence in a 3D atmosphere.
- [31] arXiv:2001.02486 [pdf, other]
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Title: Evidence for Galactic disc RR~Lyrae stars in the Solar neighbourhoodComments: 12 pages, 9 figuresSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)
We present a kinematical study of 314 RR~Lyrae stars in the solar neighbourhood using the publicly available photometric, spectroscopic, and {\it Gaia} DR2 astrometric data to explore their distribution in the Milky Way. We report an overdensity of 22 RR~Lyrae stars in the solar neighbourhood at a pericenter distance of between 5--9\,kpc from the Galactic center. Their orbital parameters and their chemistry indicate that these 22 variables share the kinematics and the [Fe/H] values of the Galactic disc, with an average metallicity and tangential velocity of [Fe/H]=$-0.60$\,dex and $v_{\theta} = 241$\,km\,s$^{-1}$, respectively. From the distribution of the Galactocentric spherical velocity components, we find that these 22 disc-like RR~Lyrae variables are not consistent with the {\it Gaia} Sausage ({\it Gaia}-Enceladus), unlike almost half of the local RR~Lyrae stars. Chemical information from the literature shows that the majority of the selected pericenter peak RR~Lyrae variables are $\alpha$-poor, a property shared by typically much younger stars in the thin disc. Using the available photometry we rule out a possible misclassification with the known classical and anomalous Cepheids. The similar kinematic, chemical, and pulsation properties of these disc RR~Lyrae stars suggest they share a common origin. In contrast, we find the RR~Lyrae stars associated with the {\it Gaia}-Enceladus based on their kinematics and chemical composition show a considerable metallicity spread in the old population ($\sim$~1\,dex).
- [32] arXiv:2001.02502 [pdf, other]
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Title: Understanding Galaxy Mergers & AGN Feedback with UVITComments: 3 pages, 2 figure, Poster presentation, Proceedings of the IAU356: Nuclear Activity in Galaxies across Cosmic Time, Addis Ababa, Ethiopia (7-11 October, 2019)Subjects: Astrophysics of Galaxies (astro-ph.GA)
Simulations expect an enhanced star-formation and active galactic nuclei (AGN) activity during galaxy mergers, which can lead to formation of binary/dual AGN. AGN feedback can enhance or suppress star-formation. We have carried out a pilot study of a sample of 10 dual nuclei galaxies with AstroSat's Ultraviolet Imaging Telescope (UVIT). Here, we present the initial results for two sample galaxies (Mrk 739, ESO 509) and deep multi-wavelength data of another galaxy (Mrk 212). UVIT observations have revealed signatures of positive AGN feedback in Mrk 739 and Mrk 212, and negative feedback in ESO 509. Deeper UVIT observations have recently been approved; these will provide better constraints on star-formation as well as AGN feedback in these systems.
- [33] arXiv:2001.02536 [pdf, other]
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Title: Constraints to dark matter annihilation from high-latitude HAWC unidentified sourcesComments: 14 pages, 4 figures, contribution to Galaxies Special Issue "The Role of Halo Substructure in Gamma-Ray Dark Matter Searches", matches the published versionJournal-ref: Galaxies 2020, 8(1), 5Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
The $\Lambda$CDM cosmological framework predicts the existence of thousands of subhalos in our own Galaxy not massive enough to retain baryons and become visible. Yet, some of them may shine in gamma rays provided that the dark matter (DM) is made of weakly interacting massive particles (WIMPs), that would self-annihilate and would appear as unidentified gamma-ray sources (unIDs) in gamma-ray catalogs. Indeed, unIDs have proven to be competitive targets for DM searches with gamma rays. In this work, we focus on the three high-latitude ($|b|\geq 10^\circ$) sources present in the 2HWC catalog of the High Altitude Water Cherenkov (HAWC) observatory with no associations at other wavelenghts. Indeed, only one of these sources, 2HWC J1040+308, is found to be above the HAWC detection threshold when considering 760 days of data, a factor 1.5 more exposure time than in the original 2HWC catalog. Other instruments such as Fermi-LAT or VERITAS at lower energies do not detect this source. Also, this unID is reported as spatially extended, making it even more interesting in a DM search context. While waiting for more data that may shed further light on the nature of this source, we set competitive upper limits on the annihilation cross section by comparing this HAWC unID to expectations based on state-of-the-art N-body cosmological simulations of the Galactic subhalo population. We find these constraints to be particularly competitive for heavy WIMPs, i.e., masses above $\sim 25$ (40) TeV in the case of the $b\bar{b}$ ($\tau^+\tau^-$) annihilation channel, reaching velocity-averaged cross section values of $2\cdot10^{-25}$ ($5\cdot10^{-25}$) $cm^3s^{-1}$. Although far from the thermal relic cross section value, the obtained limits are independent and nicely complementary to those from radically different DM analyses and targets, demonstrating again the high potential of this DM search approach.
- [34] arXiv:2001.02548 [pdf, ps, other]
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Title: On the visible continuum and bands in the interstellar extinction curve IIAuthors: Renaud PapoularComments: 11 pages, 18 figuresSubjects: Astrophysics of Galaxies (astro-ph.GA)
Any distortion of a chemical structure causes new features to appear in the absorption spectrum of the structure, especially in the visible and near UV (see Paper I). Chemical modeling, using molecular orbital theory, showed that the continuum resulting from the accumulation of weak new bands in that range, correctly mimics the continuum measured in the laboratory on pure synthesized silicates, in the transparency spectral range, as well as in the InterStellar extinction curve in the same range.
The present paper explores in more detail the strong discrete bands that emerge from the continuum due to distortion. It is found that different types of structure (linear or compact, carbon- or silicon-bearing) have each a limited number of strong, characteristic, bands at different wavelengths.
Distortion is only one instance of ``defects'' that enrich the vis/UV absorption spectrum; others are: vacancies and voids, substitutions, inclusions in interstices, impurities, dangling bonds. The accumulation of these result in an ``amorphous'' structural state. Several examples of known amorphous materials, both carbon- and silicon-bearing, that have been analyzed in the laboratory, and simulated theoretically, are described below, thus extending the scope of this work. A final section lists several fields of astrophysics that have used, or may use, amorphous models of dust. - [35] arXiv:2001.02559 [pdf, other]
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Title: Digital Infrastructure in AstrophysicsComments: 21 pages; report for the Ford and Sloan Foundation's Digital Infrastructure Research ProgramSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)
Astronomy, as a field, has long encouraged the development of free, open digital infrastructure (e.g., National Research Council 2010, 2011). Examples range from simple scripts that enable individual scientific research, through software instruments for entire communities, to data reduction pipelines for telescope operations at national facilities. As with the digital infrastructure of our larger society today (e.g., Eghbal 2016), nearly all astronomical research relies on free, open source software (FOSS) written and maintained by a small number of developers. And like the physical infrastructure of roads or bridges, digital infrastructure needs regular upkeep and maintenance (e.g., Eghbal 2016). In astronomy, financial support for maintaining existing digital infrastructure is generally much harder to secure than funding for developing new digital infrastructures that promise new science. Sustaining astronomy's digital infrastructure is a new topic for many, the sustainability challenges are not always widely known...
- [36] arXiv:2001.02560 [pdf, other]
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Title: Extending the variability selection of active galactic nuclei in the W-CDF-S and SERVS/SWIRE regionAuthors: M. Poulain, M. Paolillo, D. De Cicco, W. N. Brandt, F. E. Bauer, S. Falocco, F. Vagnetti, A. Grado, F. Ragosta, M. T. Botticella, E. Cappellaro, G. Pignata, M. Vaccari, P. Schipani, G. Covone, G. Longo, N. R. NapolitanoSubjects: Astrophysics of Galaxies (astro-ph.GA)
Variability has proven to be a powerful tool to detect active galactic nuclei (AGN) in multi-epoch surveys. The new-generation facilities expected to become operational in the next few years will mark a new era in time-domain astronomy and their wide-field multi-epoch campaigns will favor extensive variability studies. We present our analysis of AGN variability in the second half of the VST survey of the Wide Chandra Deep Field South (W-CDF-S), performed in the r band and covering a 2 sq. deg. area. The analysis complements a previous work, in which the first half of the area was investigated. We provide a reliable catalog of variable AGN candidates, which will be critical targets in future variability studies. We selected a sample of optically variable sources and made use of infrared data from the Spitzer mission to validate their nature by means of color-based diagnostics. We obtain a sample of 782 AGN candidates among which 12 are classified as supernovae, 54 as stars, and 232 as AGN. We estimate a contamination $\lesssim 20\%$ and a completeness $\sim 38\%$ with respect to mid-infrared selected samples.
- [37] arXiv:2001.02570 [pdf, other]
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Title: NuSTAR observation of Ark 564 reveals the variation of coronal temperature with fluxComments: Accepted for Publication in MNRAS, 6 Pages, 5 Figures, 2 TablesSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
The hard X-ray spectral index of some AGN has been observed to steepen with the source flux. This has been interpreted in a Comptonization scenario, where an increase in the soft flux decreases the temperature of the corona, leading to steepening of the photon index. However, the variation of the coronal temperature with flux has been difficult to measure due to the presence of complex reflection component in the hard X-rays and the lack of high-quality data at that energy band. Recently, a 200 ks {\it NuSTAR} observation of Ark 564 in 3--50 keV band, revealed the presence of one of the coolest coronae with temperature $kT_e \sim 15$ keV in the time-averaged spectrum. Here, we re-analyse the data and examined the spectra in four flux levels. Our analysis shows that the coronal temperature decreased from $\sim 17$ to $\sim 14$ keV as the flux increased. The high energy photon index $\Gamma \sim 2.3$ varied by less than $0.1$, implying that the optical depth of the corona increased by about 10\% as the flux increased. This first reporting of coronal temperature variation with flux shows that further long observation by {\it NuSTAR} of this and other sources would shed light on the geometry and dynamics of the inner regions of the accretion flow.
- [38] arXiv:2001.02572 [pdf, ps, other]
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Title: The first Doppler imaging of the active binary prototype RS Canum VenaticorumAuthors: Yue Xiang, Shenghong Gu, U. Wolter, J. H. M. M. Schmitt, A. Collier Cameron, J. R. Barnes, M. Mittag, V. Perdelwitz, S. KohlComments: 11 pages, 10 figures, accepted for publication in MNRASSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
We present the first Doppler images of the prototypical active binary star RS CVn, derived from high-resolution spectra observed in 2004, 2016 and 2017, using three different telescopes and observing sites. We apply the least-squares deconvolution technique to all observed spectra to obtain high signal-to-noise line profiles, which are used to derive the surface images of the active K-type component. Our images show a complex spot pattern on the K star, distributed widely in longitude. All starspots revealed by our Doppler images are located below a latitude of about 70$^{\circ}$. In accordance with previous light-curve modeling studies, we find no indication of a polar spot on the K star. Using Doppler images derived from two consecutive rotational cycles, we estimate a surface differential rotation rate of $\Delta\Omega = -0.039 \pm 0.003 ~rad~d^{-1}$ and $\alpha = \Delta\Omega/\Omega_{eq} = -0.030 \pm 0.002$ for the K star. Given the limited phase coverage during those two rotations, the uncertainty of our differential rotation estimate is presumably higher.
- [39] arXiv:2001.02573 [pdf, ps, other]
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Title: Understanding star formation and feedback in small galaxies. The case of the blue compact dwarf Mrk 900Authors: L. M. Cairós (1), J. N. González-Pérez (2) ((1) Institut für Astrophysik, Georg-August-Universität, Göttingen, Germany (2) Hamburger Sternwarte, Hamburg, Germany)Comments: 17 pages, 19 figures. Accepted for publication in A&ASubjects: Astrophysics of Galaxies (astro-ph.GA)
(Abridged) Low-luminosity, active star-forming blue compact galaxies (BCGs) are excellent laboratories for investigating the process of star formation on galactic scales and probing the interplay between massive stars and the surrounding interstellar (or intergalactic) medium. We investigated the morphology, structure, and stellar content of the Blue Compact Galaxy Mrk 900, combining optical integral field observations obtained with VIMOS at the VLT and deep broad-band photometry taken at the 2.5 m NOT telescope. From the integral field data, we built continuum, emission, and diagnostic line ratio maps and produced velocity and velocity dispersion maps. We also generated the integrated spectrum of the major HII regions and the nuclear area to determine reliable physical parameters and oxygen abundances. The broad-band data, tracing the galaxy up to radius 4 kpc, allowed us to investigate the properties of the low surface brightness underlying stellar host. We disentangle two different stellar components in Mrk 900: a young population, which resolves into individual stellar clusters with ages ~5.5-6.6 Myr and extends about 1 kpc along the galaxy minor axis, is placed on top of a rather red and regular shaped underlying stellar host, several Gyr old. We find evidence of a substantial amount of dust and an inhomogeneous extinction pattern, with a dust lane crossing the central starburst. Mrk 900 displays overall rotation, although distorted in the central, starburst regions; the dispersion velocity map is highly inhomogeneous, with values increasing up to 60 kms$^{-1}$ at the periphery of the SF regions, where we also find hints of the presence of shocks. Our observational results point to an interaction or merger with a low-mass object or infalling gas as plausible trigger mechanisms for the present starburst event.
- [40] arXiv:2001.02577 [pdf, other]
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Title: Search for Nearby Earth Analogs. II. detection of five new planets, eight planet candidates, and confirmation of three planets around nine nearby M dwarfsAuthors: Fabo Feng, R. Paul Butler, Stephen A. Shectman, Jeffrey D. Crane, Steve Vogt, John Chambers, Hugh R. A. Jones, Sharon Xuesong Wang, Johanna K. Teske, Jenn Burt, Matias R. Diaz, Ian B. ThompsonComments: 38 pages, 31 figures, 4 tablesJournal-ref: 2019, ApJS, 246, 11Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Zechmeister et al. (2009) surveyed 38 nearby M dwarfs from March 2000 to March 2007 with VLT2 and the UVES spectrometer. This data has recently been reanalyzed (Butler et al. 2019), yielding a significant improvement in the Doppler velocity precision. Spurred by this, we have combined the UVES data with velocity sets from HARPS, Magellan/PFS, and Keck/HIRES. Sixteen planet candidates have been uncovered orbiting nine M dwarfs. Five of them are new planets corresponding to radial velocity signals, which are not sensitive to the choice of noise models and are identified in multiple data sets over various timespans. Eight candidate planets require additional observation to be confirmed. We also confirm three previously reported planets. Among the new planets, GJ 180 d and GJ 229A c are super-Earths located in the conservative habitable zones of their host stars. We investigate their dynamical stability using the Monte Carlo approach and find both planetary orbits are robust to the gravitational perturbations of the companion planets. Due to their proximity to the Sun, the angular separation between the host stars and the potentially habitable planets in these two systems is 25 and 59 mas, respectively. They are thus good candidates for future direct imaging by JWST and E-ELT. In addition we find GJ 433 c, a cold super-Neptune belonging to an unexplored population of Neptune-like planets. With a separation of 0.5 as from its host star, GJ 433 c is probably the first realistic candidate for direct imaging of cold Neptunes. A comprehensive survey of these planets is important for the studies of planet formation.
- [41] arXiv:2001.02615 [pdf, other]
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Title: The IAG Solar Flux Atlas: Telluric Correction With a Semi-Empirical ModelComments: 20 pages, 12 figuresSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Solar and Stellar Astrophysics (astro-ph.SR)
Observations of the Sun as a star have been key to guiding models of stellar atmospheres and additionally provide useful insights on the effects of granulation and stellar activity on radial velocity measurements. Most high resolution solar atlases contain telluric lines that span the optical and limit the spectral regions useful for analysis. We present here a telluric-corrected solar atlas covering 0.5-1.0 micron derived from solar spectra taken with a Fourier Transform Spectrograph (FTS) at the Institut f\"ur Astrophysik, G\"ottingen. This atlas is the highest resolution spectrum with a wavelength calibration precise to +/-10 m/s across this 500 nm spectral window. We find that the atlas matches to within 3% of the telluric-corrected Kitt Peak atlas in regions containing telluric absorption weaker than 50% in transmission. The telluric component of the spectral data is fit with a semi-empirical model composed of Lorentz profiles initialized to the HITRAN parameters for each absorption feature. Comparisons between the best-fit telluric parameters describing the Lorentz profile for each absorption feature to the original HITRAN values in general show excellent agreement considering the effects atmospheric pressure and temperature have on our final parameters. However, we identify a small subset of absorption features with larger offsets relative to the catalogued line parameters. We make our final solar atlas available online. We additionally make available the telluric spectra extracted from the data that, given the high resolution of the spectrum, would be useful for studying the time evolution of telluric line shapes and their impact on Doppler measurements.
- [42] arXiv:2001.02618 [pdf, other]
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Title: Simulated JWST datasets for multispectral and hyperspectral image fusionSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Image and Video Processing (eess.IV)
This paper aims at providing a comprehensive framework to generate an astrophysical scene and to simulate realistic hyperspectral and multispectral data acquired by two JWST instruments, namely NIRCam Imager and NIRSpec IFU. We want to show that this simulation framework can be resorted to assess the benefits of fusing these images to recover an image of high spatial and spectral resolutions. To do so, we create a synthetic scene associated with a canonical infrared source, the Orion Bar. This scene combines pre-existing modelled spectra provided by the JWST Early Release Science Program 1288 and real high resolution spatial maps from the Hubble space and ALMA telescopes. We develop forward models including corresponding noises for the two JWST instruments based on their technical designs and physical features. JWST observations are then simulated by applying the forward models to the aforementioned synthetic scene. We test a dedicated fusion algorithm we developed on these simulated observations. We show the fusion process reconstructs the high spatio-spectral resolution scene with a good accuracy on most areas, and we identify some limitations of the method to be tackled in future works. The synthetic scene and observations presented in the paper are made publicly available and can be used for instance to evaluate instrument models (aboard the JWST or on the ground), pipelines, or more sophisticated algorithms dedicated to JWST data analysis. Besides, fusion methods such as the one presented in this paper are shown to be promising tools to fully exploit the unprecedented capabilities of the JWST.
- [43] arXiv:2001.02634 [pdf, other]
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Title: On the Lambda-evolution of galaxy clustersComments: 7 pages, 5 figs, Eur.Phys. J. C (in press)Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc)
The evolution of galaxy clusters can be affected by the repulsion described by the cosmological constant. This conclusion is reached within the modified weak-field General Relativity approach where the cosmological constant \Lambda enables to describe the common nature of the dark matter and the dark energy. Geometrical methods of theory of dynamical systems and the Ricci curvature criterion are used to reveal the difference in the instability properties of galaxy clusters which determine their evolutionary paths. Namely, it is shown that the clusters determined by the gravity with \Lambda-repulsion tend to become even more unstable than those powered only by Newtonian gravity, the effect to be felt at cosmological time scales.
- [44] arXiv:2001.02638 [pdf, other]
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Title: The New 2018 Version of the Meudon SpectroheliographComments: 14 pages, 5 figures; Published in Solar PhysicsJournal-ref: Solar Physics, May 2019, 294:52Subjects: Solar and Stellar Astrophysics (astro-ph.SR)
Daily full-disk observations of the solar photosphere and chromosphere started at Meudon Observatory in 1908. After a review of the scientific context and the historical background, we describe the instrumental characteristics and capabilities of the new version operating since 2018. The major change is the systematic recording of full line profiles over the entire solar disk providing 3D data cubes. Spectral and spatial sampling are both improved. Classical 2D images of the Sun at fixed wavelength are still delivered. We summarize the different processing levels of on-line data and briefly review the new scientific perspectives.
- [45] arXiv:2001.02640 [pdf, other]
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Title: Supernova Host Galaxies in the Dark Energy Survey: I. Deep Coadds, Photometry, and Stellar MassesAuthors: P. Wiseman, M. Smith, M. Childress, L. Kelsey, A. Möller, R. R. Gupta, E. Swann, C. R. Angus, D. Brout, T. M. Davis, R. J. Foley, C. Frohmaier, L. Galbany, C. P. Gutiérrez, R. Kessler, G. F. Lewis, C. Lidman, E. Macaulay, R. C. Nichol, M. Pursiainen, M. Sako, D. Scolnic, N. E. Sommer, M. Sullivan, B. E. Tucker, T. M. C. Abbott, M. Aguena, S. Allam, S. Avila, E. Bertin, D. Brooks, E. Buckley-Geer, D. L. Burke, A. Carnero Rosell, M. Carrasco Kind, L. N. da Costa, J. De Vicente, S. Desai, H. T. Diehl, P. Doel, T. F. Eifler, S. Everett, P. Fosalba, J. Frieman, J. García-Bellido, E. Gaztanaga, D. W. Gerdes, R. A. Gruendl, J. Gschwend, W. G. Hartley, S. R. Hinton, D. L. Hollowood, D. J. James, K. Kuehn, N. Kuropatkin, M. Lima, M. A. G. Maia, M. March, P. Martini, P. Melchior, F. Menanteau, et al. (17 additional authors not shown)Comments: 18 pages, 17 figures. Submitted to MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA)
The five-year Dark Energy Survey supernova programme (DES-SN) is one of the largest and deepest transient surveys to date in terms of volume and number of supernovae. Identifying and characterising the host galaxies of transients plays a key role in their classification, the study of their formation mechanisms, and the cosmological analyses. To derive accurate host galaxy properties, we create depth-optimised coadds using single-epoch DES-SN images that are selected based on sky and atmospheric conditions. For each of the five DES-SN seasons, a separate coadd is made from the other 4 seasons such that each SN has a corresponding deep coadd with no contaminating SN emission. The coadds reach limiting magnitudes of order $\sim 27$ in $g$-band, and have a much smaller magnitude uncertainty than the previous DES-SN host templates, particularly for faint objects. We present the resulting multi-band photometry of host galaxies for samples of spectroscopically confirmed type Ia (SNe Ia), core-collapse (CCSNe), and superluminous (SLSNe) as well as rapidly evolving transients (RETs) discovered by DES-SN. We derive host galaxy stellar masses and probabilistically compare stellar-mass distributions to samples from other surveys. We find that the DES spectroscopically confirmed sample of SNe Ia selects preferentially fewer high mass hosts at high redshift compared to other surveys, while at low redshift the distributions are consistent. DES CCSNe and SLSNe hosts are similar to other samples, while RET hosts are unlike the hosts of any other transients, although these differences have not been disentangled from selection effects.
- [46] arXiv:2001.02641 [pdf, other]
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Title: Impact of Polarized Galactic Foreground Emission on CMB Lensing Reconstruction and Delensing of B-ModesComments: 26 pages, 13 figures, comments welcomeSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
Next generation CMB experiments such as CMB-S4 aim at measuring the CMB lensing potential at sub-percent precision where most of the constraining power will come from CMB polarization. We investigate the prospects of achieving this goal in the presence of large-scale, diffuse galactic foreground emission by using non-Gaussian sky simulations and exploit multi-frequency information to clean those. We show that, while prior to foreground cleaning, cosmological parameter estimates from the contaminated lensing potential estimation can be significantly biased, these can be successfully mitigated by applying a parametric foreground cleaning approach. We further observe no significant additional bias in the delensed B-mode power spectrum after applying foreground cleaning and are therefore able to obtain an unbiased measurement of the tensor-to-scalar ratio, $r$, after delensing.
- [47] arXiv:2001.02649 [pdf, other]
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Title: Dark Matter searches through cross-correlations of gamma rays with neutral-hydrogen intensity mappingAuthors: Elena PinettiComments: Proceedings from the 16th International Conference on Topics in Astroparticle and Underground Physics (TAUP 2019)Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
In this work we derive the first theoretical prediction of the cross-correlation signal between the unresolved gamma-ray background and the 21-cm line originated by the spin-flip transition of neutral hydrogen atoms, by taking as benchmark experiment the space telescope {\it Fermi}-LAT for gamma rays and the next-generation radio telescope Square Kilometer Array (SKA) as well as its precursor MeerKAT for the 21-cm emission. The attainable bounds in the dark matter (DM) parameter space are envisioned to be competitive already with the combination {\it Fermi}-LAT $\times$ MeerKAT, but SKA will allow to go deeper and probe a thermal DM particle up to masses of 130 GeV. A future gamma-ray detector with better angular resolution and larger exposure together with an ungraded radio telescope will have the potentiality to probe a DM candidate with thermal annihilation cross-section and masses up to the TeV scale.
- [48] arXiv:2001.02651 [pdf, ps, other]
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Title: The mass of our Galaxy from satellite proper motions in the Gaia eraComments: 17 pages, 10 figures, 2 table. Resubmitted to MNRAS after first revisionSubjects: Astrophysics of Galaxies (astro-ph.GA)
We use Gaia DR2 systemic proper motions of 45 satellite galaxies to constrain the mass of the Milky Way using the scale free mass estimator of Watkins et al. (2010). We first determine the anisotropy parameter $\beta$, and the tracer satellites' radial density index $\gamma$ to be $\beta$=$-0.67^{+0.45}_{-0.62}$ and $\gamma=2.11\pm0.23$. When we exclude possible former satellites of the Large Magellanic Cloud, the anisotropy changes to $\beta$=$-0.21^{+0.37}_{-0.51}$. We find that the index of the Milky Way's gravitational potential $\alpha$, which is dependent on the mass itself, is the parameter with the largest impact on the mass determination. Via comparison with cosmological simulations of Milky Way-like galaxies, we carried out a detailed analysis of the estimation of the observational uncertainties and their impact on the mass estimator. We found that the mass estimator is biased when applied naively to the satellites of simulated Milky Way halos. Correcting for this bias, we obtain for our Galaxy a mass of $0.58^{+0.15}_{-0.14}\times10^{12}$M$_\odot$ within 64 kpc, as computed from the inner half of our observational sample, and $1.43^{+0.35}_{-0.32}\times10^{12}$M$_\odot$ within 273 kpc, from the full sample; this latter value extrapolates to a virial mass of $M_\mathrm{vir}$=$1.51^{+0.45}_{-0.40} \times 10^{12}M_{\odot}$ corresponding to a virial radius of R$_\mathrm{vir}$=$308\pm29$ kpc. This value of the Milky Way mass lies in-between other mass estimates reported in the literature, from various different methods.
- [49] arXiv:2001.02662 [pdf, other]
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Title: A Nucleosynthetic Origin for the Southwestern Fe-rich Structure in Kepler's Supernova RemnantAuthors: Toshiki Sato, Eduardo Bravo, Carles Badenes, John P. Hughes, Brian J. Williams, Hiroya YamaguchiComments: 17 pages, 12 figures, accepted for publication in ApJSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
{\it Chandra} X-ray observations of Kepler's supernova remnant indicate the existence of a high speed Fe-rich ejecta structure in the southwestern region. We report strong K-shell emission from Fe-peak elements (Cr, Mn, Fe, Ni), as well as Ca, in this Fe-rich structure, implying that those elements could be produced in the inner area of the exploding white dwarf. We found Ca/Fe, Cr/Fe, Mn/Fe and Ni/Fe mass ratios of 1.0--4.1\%, 1.0--4.6\%, 1--11\% and 2--30\%, respectively. In order to constrain the burning regime that could produce this structure, we compared these observed mass ratios with those in 18 one-dimensional Type Ia nucleosynthesis models (including both near-$M_{\rm Ch}$ and sub-$M_{\rm Ch}$ explosion models). The observed mass ratios agree well with those around the middle layer of incomplete Si-burning in Type Ia nucleosynthesis models with a peak temperature of $\sim$(5.0--5.3)$\times$10$^{9}$ K and a high metallicity, Z $>$ 0.0225. Based on our results, we infer the necessity for some mechanism to produce protruding Fe-rich clumps dominated by incomplete Si-burning products during the explosion. We also discuss the future perspectives of X-ray observations of Fe-rich structures in other Type Ia supernova remnants.
- [50] arXiv:2001.02666 [pdf, other]
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Title: The evolution of dust-disk sizes from a homogeneous analysis of 1-10 Myr-old starsAuthors: Nathanial Hendler, Ilaria Pascucci, Paola Pinilla, Marco Tazzari, John Carpenter, Renu Malhotra, Leonardo TestiComments: ApJ accepted, 38 pages, 16 figures, 68k compatibleSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)
We utilize ALMA archival data to estimate the dust disk size of 152 protoplanetary disks in Lupus (1-3 Myr), Chamaeleon I (2-3 Myr), and Upper-Sco (5-11 Myr). We combine our sample with 47 disks from Tau/Aur and Oph whose dust disk radii were estimated, as here, through fitting radial profile models to visibility data. We use these 199 homogeneously derived disk sizes to identify empirical disk-disk and disk-host property relations as well as to search for evolutionary trends. In agreement with previous studies, we find that dust disk sizes and millimeter luminosities are correlated, but show for the first time that the relationship is not universal between regions. We find that disks in the 2-3 Myr-old Cha I are not smaller than disks in other regions of similar age, and confirm the Barenfeld et al. (2017) finding that the 5-10 Myr USco disks are smaller than disks belonging to younger regions. Finally, we find that the outer edge of the Solar System, as defined by the Kuiper Belt, is consistent with a population of dust disk sizes which have not experienced significant truncation.
- [51] arXiv:2001.02667 [pdf, other]
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Title: UHECRs mass composition from $X_{\rm max}$ distributionsComments: Accepted for publication in European Physical Journal CSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
The atmospheric depth where the energy deposit profile of secondary particles from extensive air showers (EAS) reaches its maximum, $X_{\rm max}$, is related to the primary particle mass. The mass composition of the ultra-high energy cosmic rays (UHECRs) can be inferred from measurements of $X_{\rm max}$ distributions in each energy interval, by fitting these distributions with Monte Carlo (MC) templates for four primary species (p, He, N and Fe). On the basis of simulations, we show that a high abundance of some intermediate elements in the $X_{\rm max}$ distributions, e.g. Ne or Si, may affect the quality of the fit and also the reconstructed fractions of different species with respect to their true values. We propose a method for finding the "best combination" of elements in each energy interval from a larger set of primaries (p, He, C, N, O, Ne, Si and Fe) which best describes the $X_{\rm max}$ distributions. Applying this method to the $X_{\rm max}$ distributions measured by the Pierre Auger Observatory (2014), we found that the "best combination" of elements which best describe the data suggest the presence of Ne or Si in some low energy bins for the EPOS-LHC model.
Cross-lists for Thu, 9 Jan 20
- [52] arXiv:2001.02278 (cross-list from hep-ph) [pdf, ps, other]
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Title: Constraints on neutrino millicharge and charge radius from neutrino-atom scatteringAuthors: Matteo Cadeddu, Carlo Giunti, Konstantin A. Kouzakov, Yufeng Li, Alexander I. Studenikin, Yiyu ZhangComments: 3 pages in LaTex, to appear in the proceedings of the European Physical Society Conference on High Energy Physics - EPS-HEP2019 - 10-17 July, 2019, Ghent, BelgiumSubjects: High Energy Physics - Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE)
We consider possible effects of neutrino electric charge (millicharge) and charge radius on the neutrino-atom interaction processes such as (i) atomic ionization by neutrino impact and (ii) coherent elastic neutrino-nucleus scattering. The bounds on the neutrino millicharge and charge radius that follow from, respectively, the GEMMA and COHERENT experiments are presented and discussed.
- [53] arXiv:2001.02304 (cross-list from gr-qc) [pdf, other]
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Title: Spherical and cylindrical solutions in f (T) gravity by Noether Symmetry ApproachComments: 8 pagesSubjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Theory (hep-th)
We find exact solutions for f (T) teleparallel gravity for the cases of spherically and cylindrically symmetric tetrads. The adopted method is based on the search for Noether symmetries of point-like Lagrangians defined in Jordan and Einstein frames. Constants of motion are used to reduce the dynamical system.We first consider the Lagrangian defined in the Jordan frame for a spherically symmetric tetrad and, by the help of two constants of motion, we eliminate a tetrad potential and integrate the other. The more complicated structure in the Einstein frame is also overcome by the same method. After that we obtain the Jordan frame Lagrangian for a general cylindrically symmetric tetrad. Following the same procedure adopted in the spherically symmetric case, we again obtain the tetrad potentials and then the exact solutions.
- [54] arXiv:2001.02327 (cross-list from physics.comp-ph) [pdf, ps, other]
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Title: Self-gravitational Force Calculation of Second Order Accuracy Using Multigrid Method on Nested GridsComments: accepted for publication in ApJSSubjects: Computational Physics (physics.comp-ph); Instrumentation and Methods for Astrophysics (astro-ph.IM)
We present a simple and effective multigrid-based Poisson solver of second-order accuracy in both gravitational potential and forces in terms of the one, two and infinity norms. The method is especially suitable for numerical simulations using nested mesh refinement. The Poisson equation is solved from coarse to fine levels using a one-way interface scheme. We introduce anti-symmetrically linear interpolation for evaluating the boundary conditions across the multigrid hierarchy. The spurious forces commonly observed at the interfaces between refinement levels are effectively suppressed. We validate the method using two- and three-dimensional density-force pairs that are sufficiently smooth for probing the order of accuracy.
- [55] arXiv:2001.02336 (cross-list from physics.app-ph) [pdf, other]
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Title: Permittivity and permeability of epoxy-magnetite powder composites at microwave frequenciesComments: 7 pages, 18 figures, submitted to the Journal of Applied Physics (AIP)Subjects: Applied Physics (physics.app-ph); Instrumentation and Methods for Astrophysics (astro-ph.IM)
Radio, millimetre and sub-millimetre astronomy experiments as well as remote sensing applications often require castable absorbers with well known electromagnetic properties to design and realize calibration targets. In this context, we fabricated and characterized two samples using different ratios of two easily commercially available materials: epoxy (Stycast 2850FT) and magnetite ($\mathrm{Fe_{3}O_{4}}$) powder. We performed transmission and reflection measurements from 7 GHz up to 170 GHz with a VNA equipped with a series of standard horn antennas. Using an empirical model we analysed the data to extract complex permittivity and permeability from transmission data; then we used reflection data to validate the results. In this paper we present the sample fabrication procedure, analysis method, parameter extraction pipeline, and results for two samples with different epoxy-powder mass ratios.
- [56] arXiv:2001.02414 (cross-list from gr-qc) [pdf, other]
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Title: Cosmological Evolution of Two-Scalar fields Cosmology in the Jordan frameComments: 38 pages, 13 figures, no tablesSubjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Phenomenology (hep-ph)
In the present article we study the cosmological evolution of a two-scalar field gravitational theory defined in the Jordan frame. Specifically, we assume one of the scalar fields to be minimally coupled to gravity, while the second field which is the Brans-Dicke scalar field is nonminimally coupled to gravity and also coupled to the other scalar field. In the Einstein frame this theory reduces to a two-scalar field theory where the two fields can interact only in the potential term, which means that the quintom theory is recovered. The cosmological evolution is studied by analyzing the equilibrium points of the field equations in the Jordan frame. We find that the theory can describe the cosmological evolution in large scales, while inflationary solutions are also provided.
- [57] arXiv:2001.02474 (cross-list from gr-qc) [pdf, other]
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Title: Squeezing of primordial gravitational waves as quantum discordComments: 32 pages, 10 figuresSubjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO); Quantum Physics (quant-ph)
We investigate the squeezing of primordial gravitational waves(PGWs) in terms of quantum discord. We construct a classical state of PGWs without quantum discord and compare it with the Bunch-Davies vacuum. Then it is shown that the oscillatory behavior of the angular-power spectrum of the cosmic microwave background (CMB) fluctuations induced by PGWs can be the signature of the quantum discord of PGWs. In addition, we discuss quantum decoherence on the entanglement and the quantum discord of PGWs for super-horizon modes. For the state of PGWs with decoherence effect, we examine the decoherence condition and the correlation condition introduced by C. Kiefer et al. (Class. Quantum Grav. 24 (2007) 1699). We show that the decoherence condition is not sufficient for the separability of PGWs and the correlation condition implies the quantum discord of PGWs in the matter-dominated era.
- [58] arXiv:2001.02538 (cross-list from physics.space-ph) [pdf, ps, other]
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Title: Heavy Ion Acceleration by Super-Alfvenic WavesComments: 4 figuresJournal-ref: The Astrophysical Journal Letters, Volume 887, Issue 1, article id. L2, 4 pp. (2019)Subjects: Space Physics (physics.space-ph); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)
A generation mechanism of super Alfv\'{e}nic (SPA) waves in multi-ion species plasma is proposed and the associated heavy ion acceleration process is discussed. The SPA waves are thought to play important roles in particle acceleration since they have large wave electric field because of their high phase velocity. It is demonstrated by using full particle-in-cell simulation that large amplitude proton cyclotron waves, excited due to proton temperature anisotropy, nonlinearly destabilize SPA waves through parametric decay instability in a three component plasma composed of electrons, protons, and $\alpha$ particles. At the same time, $\alpha$ cyclotron waves get excited via another decay instability. A pre-accelerated $\alpha$ particle resonates simultaneously with the two daughter waves, the SPA waves and the $\alpha$ cyclotron waves, and it is further accelerated perpendicular to the ambient magnetic field. The process may work in astrophysical environments where sufficiently large temperature anisotropy of lower mass ions occurs.
- [59] arXiv:2001.02591 (cross-list from gr-qc) [pdf, other]
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Title: Growth of Linear Perturbations in a Universe with Superfluid Dark MatterComments: 16 pages, 6 figuresSubjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
The Lambda-Cold Dark Matter (LCDM) model agrees with most of the cosmological observations, but has some hindrances from observed data at smaller scales such as galaxies. Recently, Berezhiani and Khoury (2015) proposed a new theory involving interacting superfluid dark matter with three model parameters, which explains galactic dynamics with great accuracy. In the present work, we study the cosmological behaviour of this model in the linear regime of cosmological perturbations. In particular, we compute both analytically and numerically the matter linear growth factor and obtain new bounds for the model parameters which are significantly stronger than previously found. These new constraints come from the fact that structures within the superfluid dark matter framework grow quicker than in LCDM, and quite rapidly when the DM-baryon interactions are strong.
- [60] arXiv:2001.02599 (cross-list from physics.plasm-ph) [pdf, ps, other]
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Title: Thermonuclear Fusion Triggered by Collapsing Standing Whistler Waves in Magnetized Overdense PlasmasComments: 16 pages, 11 figures, accepted for publication in PRESubjects: Plasma Physics (physics.plasm-ph); High Energy Astrophysical Phenomena (astro-ph.HE)
Thermal fusion plasmas initiated by standing whistler waves are investigated numerically by two- and one-dimensional Particle-in-Cell simulations. When a standing whistler wave collapses due to the wave breaking of ion plasma waves, the energy of the electromagnetic waves transfers directly to the ion kinetic energy. Here we find that the ion heating by the standing whistler wave is operational even in multi-dimensional simulations of multi-ion species targets, such as deuterium-tritium (DT) ices and solid ammonia borane (H$_6$BN). The energy conversion efficiency to ions becomes as high as 15% of the injected laser energy, which depends significantly on the target thickness and laser pulse duration. The ion temperature could reach a few tens of keV or much higher if appropriate laser-plasma conditions are selected. DT fusion plasmas generated by this method must be useful as efficient neutron sources. Our numerical simulations suggest that the neutron generation efficiency exceeds 10$^9$ n/J per steradian, which is beyond the current achievements of the state-of-the-art laser experiments. The standing whistler wave heating would expand the experimental possibility for an alternative ignition design of magnetically confined laser fusion, and also for more difficult fusion reactions including the aneutronic proton-boron reaction.
- [61] arXiv:2001.02617 (cross-list from hep-ph) [pdf, ps, other]
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Title: Lack of Debye and Meissner screening in strongly magnetized quark matter at intermediate densitiesComments: 16 pages, 4 figuresSubjects: High Energy Physics - Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
We study the static responses of cold quark matter in the intermediate baryonic density region (characterized by a chemical potential $\mu$) in the presence of a strong magnetic field. It is shown that in that region the phase materialized by an inhomogeneous condensate formed by a particle-hole pair, the so-called Magnetic Dual Chiral Density Wave (MDCDW) phase, is more stable in the weak-coupling regime than the one considered in the magnetic catalysis of chiral symmetry braking phenomenon (MC$\chi$SB), which is formed by a constant condensate produced by a particle-antiparticle pairing, and even than the chiral symmetric phase without any condensate that was expected to be realized at sufficiently high baryonic chemical potential. The different components of the photon polarization operator of the MDCDW phase in the one-loop approximation are calculated. We found that in the MDCDW phase there is no Debye screening neither Meissner effect. The obtained Debye length depends on the amplitude $m$ and modulation $b$ of the inhomogeneous condensate and it is only different from zero if the relation $| \mu -b| > m$ holds. But, we found that in the region of interest this inequality is not satisfied. Thus, no Debye screening takes place in this dense medium. On the other hand, since the particle-hole condensate is electrically neutral, the U(1) electromagnetic group is not broken by the ground state and consequently there is no Meissner effect. These results can be of interest for the astrophysics of neutron stars.
Replacements for Thu, 9 Jan 20
- [62] arXiv:gr-qc/9910062 (replaced) [pdf, ps, other]
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Title: On the Equivalence Principle and a Unified Description of Gravitation and ElectromagnetismAuthors: Murat ÖzerComments: A new argument that produces the $g_{00}$ of the metric outside a charged sphere is presented. Existing experimental evidences for the electromagnetic equivalence principle introduced are pointed out. A new footnote has been addedSubjects: General Relativity and Quantum Cosmology (gr-qc); Astrophysics (astro-ph); High Energy Physics - Phenomenology (hep-ph); Mathematical Physics (math-ph); Quantum Physics (quant-ph)
- [63] arXiv:1801.01493 (replaced) [pdf, other]
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Title: NGC 4993 the shell galaxy host of GW170817: constraints on the recent galactic mergerComments: 11 pages, 7 figures, 1 table, accepted for publication in A&ASubjects: Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE)
- [64] arXiv:1808.07013 (replaced) [pdf, other]
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Title: Constraints on nonlinear tides due to $p$-$g$ mode coupling from the neutron-star merger GW170817Comments: 15 pages, 3 figures, submitted to ApJ, posteriors and evidences available from this https URLSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
- [65] arXiv:1811.04913 (replaced) [pdf, other]
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Title: One-form superfluids and magnetohydrodynamicsComments: v3: 69 + 1 pages, 1 figure, added clarifications and appendix with discrete symmetries, to be published in JHEPSubjects: High Energy Physics - Theory (hep-th); High Energy Astrophysical Phenomena (astro-ph.HE); Strongly Correlated Electrons (cond-mat.str-el); General Relativity and Quantum Cosmology (gr-qc); Plasma Physics (physics.plasm-ph)
- [66] arXiv:1902.08477 (replaced) [pdf, other]
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Title: Compact Star of Holographic Nuclear Matter and GW170817Comments: 7 pages, 5 figures; v2: published versionSubjects: High Energy Physics - Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Theory (hep-th)
- [67] arXiv:1902.09519 (replaced) [pdf, other]
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Title: Probing higher-spin fields from inflation with higher-order statistics of the CMBComments: v4: 26 pages, 6 figures. Fixed minor typo in Higuchi bound, Eq. (1)Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [68] arXiv:1903.08258 (replaced) [pdf, other]
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Title: Pulsar timing in extreme mass ratio binaries: a general relativistic approachComments: 19 pages, 15 Figures. Accepted for publication in MNRASSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
- [69] arXiv:1906.06701 (replaced) [pdf, other]
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Title: Constraining dark matter annihilation with HSC Low Surface Brightness GalaxiesAuthors: Daiki Hashimoto, Oscar Macias, Atsushi J. Nishizawa, Kohei Hayashi, Masahiro Takada, Masato Shirasaki, Shin'ichiro AndoComments: 19 pages, 6 figures, accepted to JCAPSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [70] arXiv:1907.06084 (replaced) [pdf, ps, other]
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Title: Energy Density, Temperature and Entropy Dynamics in Perturbative ReheatingComments: Compatible with the published PRD Version - 11 pages, 6 figuresJournal-ref: Phys. Rev. D 100, 123532 (2019)Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [71] arXiv:1907.10813 (replaced) [pdf, ps, other]
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Title: Model-independent reconstruction of $f(T)$ gravity from Gaussian ProcessesComments: 10 pages, 4 figures, 1 table; comments are welcomeJournal-ref: Astrophys.J. 888 (2020) no.2, 62Subjects: 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)
- [72] arXiv:1907.13065 (replaced) [pdf, other]
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Title: Simulation of primordial black hole formation using pseudo-spectral methodsAuthors: Albert EscrivàComments: v3: 13 pages and 13 figures. Clarifications added and plots improved. Accepted for publication in Physics of the Dark UniverseSubjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Theory (hep-th)
- [73] arXiv:1908.00604 (replaced) [pdf, other]
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Title: Characterisation of the Particle-Induced Background of XMM-Newton EPIC-pn: Short and Long Term VariabilityAuthors: Esra Bulbul, Ralph Kraft, Paul Nulsen, Michael Freyberg, Eric D. Miller, Catherine Grant, Mark W. Bautz, David N. Burrows, Steven Allen, Tanja Eraerds, Valentina Fioretti, Fabio Gasteldello, Vittorio Ghirardini, David Hall, Norbert Meidinger, Silvano Molendi, Arne Rau, Dan Wilkins, Joern WilmsComments: 18 pages, 10 figures, 5 tables. Accepted for publication in ApJSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
- [74] arXiv:1908.02534 (replaced) [pdf, ps, other]
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Title: de Sitter duality and logarithmic decay of dark energyComments: 39 pages, 1 figure, matches published versionJournal-ref: Phys. Rev. D 101, 023504 (2020)Subjects: High Energy Physics - Theory (hep-th); Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc)
- [75] arXiv:1908.02823 (replaced) [pdf, other]
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Title: The Emergence of the First Star-free Atomic Cooling Haloes in the UniverseAuthors: John A. Regan (Dublin City University), John H. Wise (Georgia Tech), Brian W. O'Shea (Michigan State), Michael L. Norman (UCSD)Comments: Minor updates after acceptance by MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [76] arXiv:1908.10865 (replaced) [pdf, other]
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Title: Atmospheric Cherenkov Telescopes as a Potential Veto Array for Neutrino AstronomyAuthors: D. Rysewyk, D. Lennarz, T. DeYoung, J. Auffenberg, M. Schaufel, T. Bretz, C. Wiebusch, M. U. NisaComments: 33 pages, 10 figures. Published by Astropart. PhysJournal-ref: Astropart.Phys. 117 (2020) 102417Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Experiment (hep-ex)
- [77] arXiv:1909.00587 (replaced) [pdf, other]
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Title: Standard Siren Speeds: Improving velocities in gravitational-wave measurements of $H_{0}$Comments: 13 pages, 5 figures. Updated to match accepted version in MNRAS; textual changes only (results/figures unchanged)Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [78] arXiv:1909.10420 (replaced) [pdf, other]
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Title: Three flavor neutrino conversions in supernovae: Slow $\&$ Fast instabilitiesComments: 22 pages, 3 figures, matches with the published versionJournal-ref: JCAP01(2020)005Subjects: High Energy Physics - Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE)
- [79] arXiv:1910.00015 (replaced) [pdf, other]
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Title: Direct Detection of Dark Matter Substructure in Strong Lens Images with Convolutional Neural NetworksComments: 12 pages+appendix, 7 figures, v2: incorporates changes in the accuracy of the network due to additional modelling steps, v3: matches published versionSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Astrophysical Phenomena (astro-ph.HE); Instrumentation and Methods for Astrophysics (astro-ph.IM); High Energy Physics - Phenomenology (hep-ph); Data Analysis, Statistics and Probability (physics.data-an)
- [80] arXiv:1910.01366 (replaced) [pdf, other]
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Title: Inferring the velocity of early massive stars from the abundances of extremely metal-poor starsComments: 25 pages, 15 figures, 6 tables, published in A&AJournal-ref: A&A 632, A62 (2019)Subjects: Solar and Stellar Astrophysics (astro-ph.SR)
- [81] arXiv:1910.01567 (replaced) [pdf, other]
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Title: Evidence for H$_{2}$ Dissociation and Recombination Heat Transport in the Atmosphere of KELT-9bAuthors: Megan Mansfield, Jacob L. Bean, Kevin B. Stevenson, Thaddeus D. Komacek, Taylor J. Bell, Xianyu Tan, Matej Malik, Thomas G. Beatty, Ian Wong, Nicolas B. Cowan, Lisa Dang, Jean-Michel Désert, Jonathan J. Fortney, B. Scott Gaudi, Dylan Keating, Eliza M.-R. Kempton, Laura Kreidberg, Michael R. Line, Vivien Parmentier, Keivan G. Stassun, Mark R. Swain, Robert T. ZellemJournal-ref: Astrophysical Journal Letters, 888, L15 (2020)Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
- [82] arXiv:1910.04894 (replaced) [pdf, other]
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Title: Multi-Scale Perturbation Theory I: Methodology and Leading-Order Bispectrum Corrections in the Matter-Dominated EraComments: 51 pages, 14 figuresSubjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [83] arXiv:1910.09476 (replaced) [pdf, other]
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Title: Gravitational wave signatures of ultralight vector bosons from black hole superradianceComments: 18 pages, 11 figures; updated to match PRD versionJournal-ref: Phys. Rev. D 101, 024019 (2020)Subjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Phenomenology (hep-ph)
- [84] arXiv:1911.08107 (replaced) [pdf, other]
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Title: The Masses of Isolated Neutron Stars Inferred from the Gravitational Redshift MeasurementsComments: 9 pages, 7 figures, 3 tables, ApJ publishedJournal-ref: 2020, ApJ, 888, 45Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)
- [85] arXiv:1911.10212 (replaced) [pdf, other]
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Title: Ionised gas outflow signatures in SDSS-IV MaNGA active galactic nucleiAuthors: Dominika Wylezalek, Anthony M. Flores, Nadia L. Zakamska, Jenny E. Greene, Rogemar A. RiffelComments: 16 pages, accepted for publication in MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA)
- [86] arXiv:1911.11570 (replaced) [pdf, other]
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Title: Magnetic energy dissipation and origin of non-thermal spectra in radiatively efficient relativistic sourcesComments: accepted for publication by MNRAS (minor changes)Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)
- [87] arXiv:1912.02056 (replaced) [pdf, other]
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Title: Exploring the latitude and depth dependence of solar Rossby waves using ring-diagram analysisComments: Submitted to and accepted by Astronomy and Astrophysics; includes minor changes from language editing reportSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
- [88] arXiv:1912.05422 (replaced) [pdf, other]
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Title: The Nucleus of Interstellar Comet 2I/BorisovComments: 24 Pages, 5 FiguresSubjects: Earth and Planetary Astrophysics (astro-ph.EP)
- [89] arXiv:1912.07255 (replaced) [pdf, other]
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Title: A detailed non-LTE analysis of LB-1: Revised parameters and surface abundancesAuthors: S. Simón-Díaz, J. Maíz Apellániz, D.J. Lennon, J.I. González Hernández, C. Allende Prieto, N. Castro, A. de Burgos, P. L. Dufton, A. Herrero, B. Toledo-Padrón, S. J. SmarttComments: Accepted for publiction in A&A on 2020/01/08Subjects: Solar and Stellar Astrophysics (astro-ph.SR)
- [90] arXiv:1912.11016 (replaced) [pdf, other]
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Title: Multipoles of the relativistic galaxy bispectrumSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [91] arXiv:2001.00755 (replaced) [pdf, other]
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Title: Unveiling the temporal properties of MAXI J1820+070 through AstroSat observationsAuthors: Sneha Prakash Mudambi, Bari Maqbool, Ranjeev Misra, Sabhya Hebbar, J. S. Yadav, Shivappa B. Gudennavar, Bubbly S. GComments: Accepted for publication in Astrophysical Journal Letters (ApJL). The article contains 8 pages, 4 figures and 1 Table. Missing reference added. Some typos correctedSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
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