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New submissions for Thu, 12 Dec 19

[1]  arXiv:1912.04903 [pdf, ps, other]

Title: Early-type Host Galaxies of Type Ia Supernovae. II. Evidence for Luminosity Evolution in Supernova Cosmology

Authors: Yijung Kang, Young-Wook Lee, Young-Lo Kim, Chul Chung, Chang Hee Ree

Comments: Accepted for publication in ApJ; see Figure 16 for the luminosity evolution mimicking dark energy

Subjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)

The most direct and strongest evidence for the presence of dark energy is provided by the measurement of galaxy distances using type Ia supernovae (SNe Ia). This result is based on the assumption that the corrected brightness of SN Ia through the empirical standardization would not evolve with look-back time. Recent studies have shown, however, that the standardized brightness of SN Ia is correlated with host morphology, host mass, and local star formation rate, suggesting a possible correlation with stellar population property. In order to understand the origin of these correlations, we have continued our spectroscopic observations to cover most of the reported nearby early-type host galaxies. From high-quality (signal-to-noise ratio ~175) spectra, we obtained the most direct and reliable estimates of population age and metallicity for these host galaxies. We find a significant correlation between SN luminosity (after the standardization) and stellar population age at a 99.5% confidence level. As such, this is the most direct and stringent test ever made for the luminosity evolution of SN Ia. Based on this result, we further show that the previously reported correlations with host morphology, host mass, and local star formation rate are most likely originated from the difference in population age. This indicates that the light-curve fitters used by the SNe Ia community are not quite capable of correcting for the population age effect, which would inevitably cause a serious systematic bias with look-back time. Notably, taken at face values, a significant fraction of the Hubble residual used in the discovery of the dark energy appears to be affected by the luminosity evolution. We argue, therefore, that this systematic bias must be considered in detail in SN cosmology before proceeding to the details of the dark energy.

[2]  arXiv:1912.04904 [pdf, other]

Title: Mass-Metallicity Trends in Transiting Exoplanets from Atmospheric Abundances of H$_2$O, Na, and K

Authors: Luis Welbanks, Nikku Madhusudhan, Nicole F. Allard, Ivan Hubeny, Fernand Spiegelman, Thierry Leininger

Comments: Accepted for publication in The Astrophysical Journal Letters

Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)

Atmospheric compositions can provide powerful diagnostics of formation and migration histories of planetary systems. We investigate constraints on atmospheric abundances of H$_2$O, Na, and K, in a sample of transiting exoplanets using latest transmission spectra and new H$_2$ broadened opacities of Na and K. Our sample of 19 exoplanets spans from cool mini-Neptunes to hot Jupiters, with equilibrium temperatures between $\sim$300 and 2700 K. Using homogeneous Bayesian retrievals we report atmospheric abundances of Na, K, and H$_2$O, and their detection significances, confirming 6 planets with strong Na detections, 6 with K, and 14 with H$_2$O. We find a mass-metallicity trend of increasing H$_2$O abundances with decreasing mass, spanning generally substellar values for gas giants and stellar/superstellar for Neptunes and mini-Neptunes. However, the overall trend in H$_2$O abundances, from mini-Neptunes to hot Jupiters, is significantly lower than the mass-metallicity relation for carbon in the solar system giant planets and similar predictions for exoplanets. On the other hand, the Na and K abundances for the gas giants are stellar or superstellar, consistent with each other, and generally consistent with the solar system metallicity trend. The H$_2$O abundances in hot gas giants are likely due to low oxygen abundances relative to other elements rather than low overall metallicities, and provide new constraints on their formation mechanisms. The differing trends in the abundances of species argue against the use of chemical equilibrium models with metallicity as one free parameter in atmospheric retrievals, as different elements can be differently enhanced.

[3]  arXiv:1912.04906 [pdf, other]

Title: Counting on Short Gamma-Ray Bursts: Gravitational-Wave Constraints of Jet Geometry

Authors: Amanda Farah, Reed Essick, Zoheyr Doctor, Maya Fishbach, Daniel E. Holz

Comments: 11 pages, 6 figures

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc)

The detection of GW170817 in gravitational waves and gamma rays revealed that short gamma-ray bursts are associated with the merger of neutron-stars. Gamma rays are thought to result from the formation of collimated jets, but the details of this process continue to elude us. One fundamental observable is the emission profile of the jet as a function of viewing angle. We present two methods to measure the effective angular width, $\theta_B$, of short gamma-ray burst (sGRB) jets using gravitational wave and gamma-ray data, assuming all sGRBs have the same angular dependence for their luminosities. The first is a counting experiment, where we combine the known detection thresholds of the LIGO/Virgo and Fermi Gamma Ray Burst Monitor detectors to infer parameters of systems that are detected in gravitational waves. This method requires minimal knowledge about each event, beyond whether or not they were detected in gamma-rays. The second method uses additional information from the gravitational-wave and electromagnetic data to estimate parameters of the source, and thereby improve constraints on jet properties. Applying our methods to GW170817, we find only weak constraints on the sGRB luminosity profile, with statistical uncertainty dominating differences between models. We also analyze simulated events from future observing runs, and find that with 5 and 100 BNS detections, the counting method constrains the relative uncertainty in $\theta_B$ to within 51% and 12%, respectively. Incorporating gravitational-wave parameter estimation would further tighten these constraints to 43% and 9.6%. In the limit of many detections, incorporating parameter estimation achieves only marginal improvements; we conclude that the majority of the information about jet structure comes from the relative sensitivities of gravitational-wave and gamma-ray detectors as encoded in simple counting experiments.

[4]  arXiv:1912.04908 [pdf, ps, other]

Title: UV and NIR size of the low-mass field galaxies: the UV compact galaxies

Authors: Cheng Cheng, Cong Kevin Xu, Lizhi Xie, Zhizheng Pan, Wei Du, Gustavo Orellana-González, Xu Shao, Shumei Wu, Roger Leiton, Jia-Sheng Huang, Sophia Yu Dai, Paulina Assmann, Nicole Araneda

Comments: 10 pages, 10 Figures, accepted by A&A

Subjects: Astrophysics of Galaxies (astro-ph.GA)

Most of the massive star-forming galaxies are found to have `inside-out' stellar mass growth modes, which means the inner parts of the galaxies mainly consist of the older stellar population, while the star forming in the outskirt of the galaxy is still ongoing. The high-resolution HST images from Hubble Deep UV Legacy Survey (HDUV) and Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) projects with the unprecedented depth in both F275W and F160W bands are the perfect data sets to study the forming and formed stellar distribution directly. We selected the low redshift ($0.05 < z_{\rm spec} < 0.3$) galaxy sample from the GOODS-North field where the HST F275W and F160W images are available. Then we measured the half light radius in F275W and F160W bands, which are the indicators of the star formation and stellar mass. By comparing the F275W and F160W half light radius, we find the massive galaxies are mainly follow the `inside-out' growth which is consistent with the previous results. Moreover, the HST F275W and F160W images reveal that some of the low-mass galaxies ($<10^8M_\odot$) have the `outside-in' growth mode: their images show a compact UV morphology, implying an ongoing star formation in the galaxy centre, the stars in the outskirts of the galaxies are already formed. The two modes transit smoothly at stellar mass range about $10^{8-9}M_\odot$ with a large scatter. We also try to identify the possible neighbour massive galaxies from the SDSS data, which represent the massive galaxy sample. We find that all of the spec-z selected galaxies have no massive galaxy nearby. Thus the `outside-in' mode we find in the low-mass galaxies are not likely originated from the environment.

[5]  arXiv:1912.04909 [pdf, other]

Title: The Aarhus Red Giants Challenge I: Stellar structures in the red giant branch phase

Authors: V. Silva Aguirre, J. Christensen-Dalsgaard, S. Cassisi, M. Miller Bertolami, A. M. Serenelli, D. Stello, A. Weiss, G. Angelou, C. Jiang, Y. Lebreton, F. Spada, E. P. Bellinger, S. Deheuvels, R. M. Ouazzani, A. Pietrinferni, J. R. Mosumgaard, R. H. D. Townsend, T. Battich, D. Bossini, T. Constantino, P. Eggenberger, S. Hekker, A. Mazumdar, A. Miglio, K. B. Nielsen, M. Salaris

Comments: accepted for publication in Astronomy and Astrophysics

Subjects: Solar and Stellar Astrophysics (astro-ph.SR)

(Abridged). We introduce the Aarhus Red Giants Challenge, a series of detailed comparisons between widely used stellar evolution and oscillation codes aiming at establishing the minimum level of uncertainties in properties of red giants arising solely from numerical implementations. Using 9 state-of-the-art stellar evolution codes, we defined a set of input physics and physical constants for our calculations and calibrated the convective efficiency to a specific point on the main sequence. We produced evolutionary tracks and stellar structure models at fixed radius along the red-giant branch for masses of 1.0 M$_\odot$, 1.5 M$_\odot$, 2.0 M$_\odot$, and 2.5 M$_\odot$, and compared the predicted stellar properties. Once models have been calibrated on the main sequence we find a residual spread in the predicted effective temperatures across all codes of ~20 K at solar radius and ~30-40 K in the RGB regardless of the considered stellar mass. The predicted ages show variations of 2-5% (increasing with stellar mass) which we track down to differences in the numerical implementation of energy generation. The luminosity of the RGB-bump shows a spread of about 10% for the considered codes, which translates into magnitude differences of ~0.1 mag in the optical V-band. We also compare the predicted [C/N] abundance ratio and found a spread of 0.1 dex or more for all considered masses. Our comparisons show that differences at the level of a few percent still remain in evolutionary calculations of red giants branch stars despite the use of the same input physics. These are mostly due to differences in the energy generation routines and interpolation across opacities, and call for further investigations on these matters in the context of using properties of red giants as benchmarks for astrophysical studies.

[6]  arXiv:1912.04910 [pdf, other]

Title: A hidden friend for the galactic center black hole, Sgr A*

Authors: Smadar Naoz, Clifford M. Will, Enrico Ramirez-Ruiz, Aurelien Hees, Andrea M. Ghez, Tuan Do

Comments: 9 pages, 6 figures, accepted to ApJ-Lett

Subjects: Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc)

The hierarchical nature of galaxy formation suggests that a supermassive black hole binary could exist in our galactic center. We propose a new approach to constraining the possible orbital configuration of such a binary companion to the galactic center black hole Sgr A* through the measurement of stellar orbits. Focusing on the star S0-2, we show that requiring its orbital stability in the presence of a companion to Sgr A* yields stringent constraints on the possible configurations of such a companion. Furthermore, we show that precise measurements of {\it time variations} in the orbital parameters of S0-2 could yield stronger constraints. Using existing data on S0-2 we derive upper limits on the binary black hole separation as a function of the companion mass. For the case of a circular orbit, we can rule out a 10^5 M_sun companion with a semimajor axis greater than 170 astronomical units or 0.8 mpc. This is already more stringent than bounds obtained from studies of the proper motion of Sgr A*. Including other stars orbiting the galactic center should yield stronger constraints that could help uncover the presence of a companion to Sgr A*. We show that a companion can also affect the accretion process, resulting in a variability which may be consistent with the measured infrared flaring timescales and amplitudes. Finally, if such a companion exists, it will emit gravitational wave radiation, potentially detectable with LISA.

[7]  arXiv:1912.04911 [pdf, other]

Title: The widest H$α$ survey of accreting protoplanets around nearby transition disks

Authors: A. Zurlo, G. Cugno, M. Montesinos, H. Canovas, S. Casassus, V. Christiaens, L. Cieza, N. Huelamo, S. Perez

Comments: Accepted for publication in A&A. 10 pages, 16 figures

Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM); Solar and Stellar Astrophysics (astro-ph.SR)

Mechanisms of planet formation are still under debate.Little we know about how planets form, even if $\sim$4000 exoplanets have been detected.Recent investigations target the cot of new born planets: the protoplanetary disk.At the first stages of their life,exoplanets are still accreting material from the gas rich disk.Transitional disks are indeed disks that show peculiarities such as gaps,spiral arms,rings which can be connected to the presence of substellar companions.To investigate on the responsible(s) of these features,we selected all the known TDs in the solar neighborhood (<200 pc) visible from the Southern hemisphere.We conducted a survey of 11 TDs with SPHERE.This is the largest Ha survey to look for protoplanets conducted so far.The observations were performed with the Ha filter of ZIMPOL,to target protoplanets that are still in the accretion stage.All the selected targets are very young stars(<20 Myr), and show low extinction in the visible.We reduced the pupil stabilized data applying the method of the ADI,which combines angular and spectral differential imaging.The datacubes are composed of the CntHa and the Ha filter taken simultaneously, to permit the suppression of the speckle pattern.PCA method was employed for the reduction of the data. For each dataset we derived the contrast limit and convert it in upper limits on the accretion luminosity.We do not detect any new accreting substellar companion around the targeted transition disks down to an average contrast of 12 mag at 0,2'' from the central star.We recovered the signal of the accreting companion around the star HD142527.We have resolved for the first time the quadruple system HD98800.For each other system we can exclude the presence of massive actively accreting companions,assuming that the accretion is not episodic and that the extinction is negligible.The mean accretion luminosity limit is 10e-6 L_S at 0,2''.

[8]  arXiv:1912.04914 [pdf, other]

Title: Modeling Dust and Starlight in Galaxies Observed by Spitzer and Herschel: The KINGFISH Sample

Authors: G. Aniano, B.T. Draine, L.K. Hunt, K. Sandstrom, D. Calzetti, R.C. Kennicutt, D.A. Dale, M. Galametz, K.D. Gordon, A.K. Leroy, J.-D.T. Smith, H. Roussel, M. Sauvage, F. Walter, L. Armus, A.D. Bolatto, M. Boquien, A. Crocker, I. De Looze, J. Donovan Meyer, G. Helou, J. Hinz, B.D. Johnson, J. Koda, A. Miller, E. Montiel, E.J. Murphy, M. Relano, H.-W. Rix, E. Schinnerer, R. Skibba, M.G. Wolfire, C.W. Engelbracht

Comments: ApJ, accepted

Subjects: Astrophysics of Galaxies (astro-ph.GA)

Dust and starlight are modeled for the KINGFISH project galaxies. With data from 3.6 micron to 500 micron, models are strongly constrained. For each pixel in each galaxy we estimate (1) dust surface density; (2) q_PAH, the dust mass fraction in PAHs; (3) distribution of starlight intensities heating the dust; (4) luminosity emitted by the dust; and (5) dust luminosity from regions with high starlight intensity. The models successfully reproduce both global and resolved spectral energy distributions. We provide well-resolved maps for the dust properties. As in previous studies, we find q_PAH to be an increasing function of metallicity, above a threshold Z/Z_sol approx 0.15. Dust masses are obtained by summing the dust mass over the map pixels; these "resolved" dust masses are consistent with the masses inferred from model fits to the global photometry. The global dust-to-gas ratios obtained from this study correlate with galaxy metallicities. Systems with Z/Z_sol > 0.5 have most of their refractory elements locked up in dust, whereas when Z/Z_sol < 0.3 most of these elements tend to remain in the gas phase. Within galaxies, we find that q_PAH is suppressed in regions with unusually warm dust with nu L_nu(70 um) > 0.4L_dust. With knowledge of one long-wavelength flux density ratio (e.g., f_{160}/f_{500}), the minimum starlight intensity heating the dust (U_min) can be estimated to within ~50%. For the adopted dust model, dust masses can be estimated to within ~0.07 dex accuracy using the 500 micron luminosity nu L_nu(500) alone. There are additional systematic errors arising from the choice of dust model, but these are hard to estimate. These calibrated prescriptions may be useful for studies of high-redshift galaxies.

[9]  arXiv:1912.04916 [pdf, other]

Title: Characterising the Dynamo in a Radiatively Inefficient Accretion Flow

Authors: Prasun Dhang, Abhijit Bendre, Prateek Sharma, Kandaswamy Subramanian

Comments: 13 pages, 11 figures, submitted to MNRAS. We welcome comments

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

We explore the MRI driven dynamo in a radiatively inefficient accretion flow (RIAF) using the mean field dynamo paradigm. Using singular value decomposition (SVD) we obtain the least squares fitting dynamo coefficients $\alpha$ and $\gamma$ by comparing the time series of the turbulent electromotive force and the mean magnetic field. Our study is the first one to show the poloidal distribution of these dynamo coefficients in global accretion flow simulations. Surprisingly, we obtain a high value of the turbulent pumping coefficient $\gamma$ which transports the mean magnetic flux radially outward. This would have implications for the launching of magnetised jets which are produced efficiently in presence a large-scale poloidal magnetic field close to the compact object. We present a scenario of a truncated disc beyond the RIAF where a large scale dynamo-generated poloidal magnetic field can aid jet-launching close to the black hole. Magnitude of all the calculated coefficients decreases with radius. Meridional variations of $\alpha_{\phi \phi}$, responsible for toroidal to poloidal field conversion, is very similar to that found in shearing box simulations using the `test field' (TF) method. By estimating the relative importance of $\alpha$-effect and shear, we conclude that the MRI driven large-scale dynamo, which operates at high latitudes beyond a disc scale height, is essentially of the $\alpha-\Omega$ type.

[10]  arXiv:1912.04921 [pdf, other]

Title: CMB distance priors revisited: effects of dark energy dynamics, spatial curvature, primordial power spectrum, and neutrino parameters

Authors: Zhongxu Zhai, Chan-Gyung Park, Yun Wang, Bharat Ratra

Comments: 10 pages, 6 figures, 1 table; comments welcome

Subjects: 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)

As a physical and sufficient compression of the full CMB data, the CMB distance priors, or shift parameters, have been widely used and provide a convenient way to include CMB data when obtaining cosmological constraints. In this paper, we revisit this data vector and examine its stability under different cosmological models. We find that the CMB distance priors are an accurate substitute for the full CMB data when probing dark energy dynamics. This is true when the primordial power spectrum model is directly generalized from the power spectrum of the model used in the derivation of the distance priors from the CMB data. We discover a difference when a non-flat model with the untilted primordial inflation power spectrum is used to measure the distance priors. This power spectrum is a radical change from the more conventional tilted primordial power spectrum and violates fundamental assumptions for the reliability of the CMB shift parameters. We also investigate the performance of CMB distance priors when the sum of neutrino masses $\sum m_{\nu}$ and the effective number of relativistic species $N_{\text{eff}}$ are allowed to vary. Our findings are consistent with earlier results: the neutrino parameters can change the measurement of the sound horizon from CMB data, and thus the CMB distance priors. We find that when the neutrino model is allowed to vary, the cold dark matter density $\omega_{c}$ and $N_{\text{eff}}$ need to be included in the set of parameters that summarize CMB data, in order to reproduce the constraints from the full CMB data. We present an updated and expanded set of CMB distance priors which can reproduce constraints from the full CMB data within $1\sigma$, and are applicable to models with massive neutrinos, as well as non-standard cosmologies.

[11]  arXiv:1912.04923 [pdf, ps, other]

Title: The Gas Accretion History of Low Mass Halos within the Cosmic Web from Cosmological Simulations

Authors: Kyungwon Chun, Rory Smith, Jihye Shin, Sungsoo S. Kim, Mojtaba Raouf

Comments: 14 pages, 9 figures. Accepted for publication in The Astrophysical Journal, November 23rd, 2019

Subjects: Astrophysics of Galaxies (astro-ph.GA)

Using high resolution hydrodynamical cosmological simulations, we study the gas accretion history of low mass halos located in a field-like, low density environment. We track their evolution individually from the early, pre-reionization era, through reionization, and beyond until $z=0$. Before reionization, low mass halos accrete cool cosmic web gas at a very rapid rate, often reaching the highest gas mass they will ever have. But when reionization occurs, we see that almost all halos lose significant quantities of their gas content, although some respond less quickly than others. We find that the response rate is influenced by halo mass first, and secondarily by their internal gas density at the epoch of reionization. Reionization also fully ionises the cosmic web gas by z$\sim$6. As a result, the lowest mass halos (M$\sim$10$^6~h^{-1}$M$_\odot$ at $z=6$) can never again re-accrete gas from the cosmic web, and by $z\sim5$ have lost all their internal gas to ionisation, resulting in a halt in star formation at this epoch. However, more massive halos can recover from their gas mass loss, and re-accrete ionised cosmic web gas. We find the efficiency of this re-accretion is a function of halo mass first, followed by local surrounding gas density. Halos that are closer to the cosmic web structure can accrete denser gas more rapidly. We find that our lower mass halos have a sweet spot for rapid, dense gas accretion at distances of roughly 1-5 virial radii from the most massive halos in our sample ($>$10$^8~h^{-1}$M$_\odot$), as these tend to be embedded deeply within the cosmic web.

[12]  arXiv:1912.04936 [pdf, other]

Title: The energy budgets of giant impacts

Authors: Philip J Carter, Simon J Lock, Sarah T Stewart

Comments: 16 pages, 11 figures. Accepted for publication in JGR: Planets. Supplementary material is available from this http URL . Accompanying animations are available from this http URL

Subjects: Earth and Planetary Astrophysics (astro-ph.EP)

Giant impacts dominate the final stages of terrestrial planet formation and set the configuration and compositions of the final system of planets. A giant impact is believed to be responsible for the formation of Earth's Moon, but the specific impact parameters are under debate. Because the canonical Moon-forming impact is the most intensely studied scenario, it is often considered the archetypal giant impact. However, a wide range of impacts with different outcomes are possible. Here we examine the total energy budgets of giant impacts that form Earth-mass bodies and find that they differ substantially across the wide range of possible Moon-forming events. We show that gravitational potential energy exchange is important, and we determine the regime in which potential energy has a significant effect on the collision outcome. Energy is deposited heterogeneously within the colliding planets, increasing their internal energies, and portions of each body attain sufficient entropy for vaporization. After gravitational re-equilibration, post-impact bodies are strongly thermally stratified, with varying amounts of vaporized and supercritical mantle. The canonical Moon-forming impact is a relatively low energy event and should not be considered the archetype of accretionary giant impacts that form Earth-mass planets. After a giant impact, bodies are significantly inflated in size compared to condensed planets of the same mass, and there are substantial differences in the magnitudes of their potential, kinetic and internal energy components. As a result, the conditions for metal-silicate equilibration and the subsequent evolution of the planet may vary widely between different impact scenarios.

[13]  arXiv:1912.04956 [pdf, other]

Title: Dynamics of Laterally Propagating Flames in X-ray Bursts. I. Burning Front Structure

Authors: Kiran Eiden, Michael Zingale, Alice Harpole, Donald Willcox, Yuri Cavecchi, Max P. Katz

Comments: Submitted to ApJ

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

We investigate the structure of laterally-propagating flames through the highly-stratified burning layer in an X-ray burst. Two-dimensional hydrodynamics simulations of flame propagation are performed through a rotating plane-parallel atmosphere, exploring the structure of the flame. We discuss the approximations needed to capture the length and time scales at play in an X-ray burst and describe the flame acceleration observed. Our studies complement other multidimensional studies of burning in X-ray bursts.

[14]  arXiv:1912.04963 [pdf, other]

Title: Detailed Abundances in the Ultra-faint Magellanic Satellites Carina II and III

Authors: Alexander P. Ji, Ting S. Li, Joshua D. Simon, Jennifer Marshall, Kathy Vivas, Andrew B. Pace, Keith Bechtol, Alex Drlica-Wagner, Sergey E. Koposov, Terese T. Hansen, Sahar Allam, Robert A. Gruendl, Michael D. Johnson, Mitch McNanna, Noelia E. De. Noel, Douglas L. Tucker, Alistair R. Walker, MagLiteS Collaboration

Comments: 21 pages + appendix, 9 figures, 6 tables, accepted to ApJ

Subjects: Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)

We present the first detailed elemental abundances in the ultra-faint Magellanic satellite galaxies Carina II (Car II) and Carina III (Car III). With high-resolution Magellan/MIKE spectroscopy, we determined abundances of nine stars in Car II including the first abundances of an RR Lyrae star in an ultra-faint dwarf galaxy; and two stars in Car III. The chemical abundances demonstrate that both systems are clearly galaxies and not globular clusters. The stars in these galaxies mostly display abundance trends matching those of other similarly faint dwarf galaxies: enhanced but declining [alpha/Fe] ratios, iron-peak elements matching the stellar halo, and unusually low neutron-capture element abundances. One star displays a low outlying [Sc/Fe] = -1.0. We detect a large Ba scatter in Car II, likely due to inhomogeneous enrichment by low-mass AGB star winds. The most striking abundance trend is for [Mg/Ca] in Car II, which decreases from +0.4 to -0.4 and indicates clear variation in the initial progenitor masses of enriching core-collapse supernovae. So far, the only ultra-faint dwarf galaxies displaying a similar [Mg/Ca] trend are likely satellites of the Large Magellanic Cloud. We find two stars with [Fe/H] < -3.5, whose abundances likely trace the first generation of metal-free Population III stars and are well-fit by Population III core-collapse supernova yields. An appendix describes our new abundance uncertainty analysis that propagates line-by-line stellar parameter uncertainties.

[15]  arXiv:1912.04970 [pdf, other]

Title: AUTO-MULTITHRESH: A General Purpose Automasking Algorithm

Authors: Amanda A. Kepley, Takahiro Tsutsumi, Crystal L. Brogan, Remy Indebetouw, Ilsang Yoon, Brian Mason, Brian Mason

Comments: accepted to PASP

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)

Producing images from interferometer data requires accurate modeling of the sources in the field of view, which is typically done using the CLEAN algorithm. Given the large number of degrees of freedom in interferometeric images, one constrains the possible model solutions for CLEAN by masking regions that contain emission. Traditionally this process has largely been done by hand. This approach is not possible with today's large data volumes which require automated imaging pipelines. This paper describes an automated masking algorithm that operates within CLEAN called AUTO-MULTITHRESH. This algorithm was developed and validated using a set of ~1000 ALMA images chosen to span a range of intrinsic morphology and data characteristics. It takes a top-down approach to producing masks: it uses the residual images to identify significant peaks and then expands the mask to include emission associated with these peaks down to lower signal-to-noise noise. The AUTO-MULTITHRESH algorithm has been implemented in CASA and has been used in production as part of the ALMA Imaging Pipeline starting with Cycle 5. It has been shown to be able to mask a wide range of emission ranging from simple point sources to complex extended emission with minimal tuning of the parameters based on the point spread function of the data. Although the algorithm was developed for ALMA, it is general enough to have been used successfully with data from other interferometers with appropriate parameter tuning. Integrating the algorithm more deeply within the minor cycle could lead to future performance improvements.

[16]  arXiv:1912.04983 [pdf, other]

Title: The ACCELERATION programme: I. Cosmology with the redshift drift

Authors: Ryan Cooke (Centre for Extragalactic Astronomy, Durham University)

Comments: 15 pages, 9 figures, Accepted for publication in Monthly Notices of the Royal Astronomical Society

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA)

Detecting the change of a cosmological object's redshift due to the time evolution of the Universal expansion rate is an ambitious experiment that will be attempted with future telescope facilities. In this paper, we describe the ACCELERATION programme, which aims to study the properties of the most underdense regions of the Universe. One of the highlight goals of this programme is to prepare for the redshift drift measurement. Using the EAGLE cosmological hydrodynamic simulations, we estimate the peculiar acceleration of gas in galaxies and in the Lya forest. We find that star-forming 'cold neutral gas' exhibits large peculiar acceleration due to the high local density of baryons near star-forming regions. We conclude that absorption by cold neutral gas is unlikely to yield a detection of the cosmological redshift drift. On the other hand, we find that the peculiar accelerations of Lya forest absorbers are more than an order of magnitude below the expected cosmological signal. We also highlight that the numerous low H I column density systems display lower peculiar acceleration. Finally, we propose a new 'Lya cell' technique that applies a small correction to the wavelength calibration to secure a relative measurement of the cosmic drift between two unrelated cosmological sources at different redshifts. For suitable combinations of absorption lines, the cosmological signal can be more than doubled, while the affect of the observer peculiar acceleration is mitigated. Using current data of four suitable Lya cells, we infer a limit on the cosmological redshift drift to be dv/dt_obs < 65 m/s/year (2 sigma).

[17]  arXiv:1912.05117 [pdf, ps, other]

Title: Recent bounds on graviton mass using galaxy clusters

Authors: Shantanu Desai, Sajal Gupta

Comments: 4 pages. TAUP 2019 conference proceedings

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc)

Although galaxy clusters have proved to be wonderful laboratories for testing a plethora of modified gravity theories and other exotic alternatives to $\Lambda$CDM, until a few years ago, there was only one paper (from 1974), which obtained a limit on graviton mass of $\mathcal{O}(10^{-29})$ eV with clusters. To rectify this, in the last few years multiple works have obtained different bounds on graviton mass using single cluster data as well as stacking galaxy catalogs. We review these recent limits on graviton mass using galaxy clusters obtained using disparate methods.

[18]  arXiv:1912.05192 [pdf, other]

Title: Measuring precise radial velocities on individual spectral lines : II. Dependance of stellar activity signal on line depth

Authors: M. Cretignier, X. Dumusque, R. Allart, F. Pepe, C. Lovis

Comments: 9 pages (main text), 9 pages (appendices), 9 figures (main text)

Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM); Solar and Stellar Astrophysics (astro-ph.SR)

Context. Although the new generation of radial-velocity (RV) instruments such as ESPRESSO are expected to reach the long-term precision required to find other earths, the RV measurements are contaminated by some signal from stellar activity. This makes these detections hard. Aims. On real observations, we here demonstrate for the first time the effect of stellar activity on the RV of individual spectral lines. Recent studies have shown that this is probably the key for mitigating this perturbing signal. Results. We estimate that at least 89% of the lines that appear in the spectrum of alpha Cen B for which we measure a reliable RV are correlated with the stellar activity signal. This can be interpreted as those lines being sensitive to the inhibition of the convective blueshift observed in active regions. Because the velocity of the convective blueshift increases with physical depth inside the stellar atmosphere, we find that the effect induced by stellar activity on the RV of individual spectral lines is inversely proportional to the line depth. The stellar activity signal can be mitigated down to 0.8-0.9 m/s, either by selecting lines that are less sensitive to activity or by using the difference between the RV of the spectral lines that are formed at different depths in the stellar atmosphere as an activity proxy. Conclusions. This paper shows for the first time that based on real observations of solar-type stars, it is possible to measure the RV effect of stellar activity on the RV of individual spectral lines. Our results are very promising and demonstrate that analysing the RV of individual spectral lines is probably one of the solutions to mitigate stellar activity signal in RV measurements down to a level enabling the detection of other earths.

[19]  arXiv:1912.05206 [pdf, ps, other]

Title: The Strength of the 2175Å Feature in the Attenuation Curves of Galaxies at 0.1<z<3

Authors: A. J. Battisti, E. da Cunha, I. Shivaei, D. Calzetti

Comments: 20 pages, 10 figures, 2 tables. Accepted for publication in ApJ. The updated MAGPHYS highz code can be downloaded at this http URL

Subjects: Astrophysics of Galaxies (astro-ph.GA)

We update the spectral modeling code MAGPHYS to include a 2175\AA\ absorption feature in its UV-to-near-IR dust attenuation prescription. This allows us to determine the strength of this feature and the shape of the dust attenuation curve in ~5000 star-forming galaxies at 0.1<z<3 in the COSMOS field. We find that a 2175\AA\ absorption feature of ~1/3 the strength of that in the Milky Way is required for models to minimize residuals. We characterize the total effective dust attenuation curves as a function of several galaxy properties and find that the UV slopes of the attenuation curve for COSMOS galaxies show a strong dependence with star formation rate (SFR) and total dust attenuation ($A_V$), such that galaxies with higher SFR and $A_V$ have shallower curves and vice versa. These results are consistent with expectations from radiative transfer that attenuation curves become shallower as the effective dust optical depth increases. We do not find significant trends in the strength of the 2175\AA\ absorption feature as a function of galaxy properties, but this may result from the high uncertainties associated with this measurement. The updated code is publicly available online.

[20]  arXiv:1912.05207 [pdf, other]

Title: Mercury, Moon, Mars: Surface expressions of mantle convection and interior evolution of stagnant-lid bodies

Authors: Nicola Tosi, Sebastiano Padovan

Comments: 45 pages, 6 figures, Accepted chapter to appear in "Mantle Convection and Surface Expressions", H. Marquardt, M. Ballmer, S. Cottar, K. Jasper (eds.), AGU Monograph Series

Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Geophysics (physics.geo-ph)

The evolution of the interior of stagnant-lid bodies is comparatively easier to model and predict with respect to the Earth's due to the absence of the large uncertainties associated with the physics of plate tectonics, its onset time and efficiency over the planet's history. Yet, the observational record for these bodies is both scarcer and sparser with respect to the Earth's. It is restricted to a limited number of samples and a variety of remote-sensing measurements of billions-of-years-old surfaces whose actual age is difficult to determine precisely. Combining these observations into a coherent picture of the thermal and convective evolution of the planetary interior represents thus a major challenge. In this chapter, we review key processes and (mostly geophysical) observational constraints that can be used to infer the global characteristics of mantle convection and thermal evolution of the interior of Mercury, the Moon and Mars, the three major terrestrial bodies where a stagnant lid has likely been present throughout most of their history.

[21]  arXiv:1912.05219 [pdf, other]

Title: Hypothetical hyperbolic encounters between Venus and proto-Mercury that partially \ stripped away proto-Mercury's mantle

Authors: Hongping Deng

Subjects: Earth and Planetary Astrophysics (astro-ph.EP)

Mercury has an unusually large metal core comprising ~70% of its mass comparing to all other terrestrial planets in the solar system. Giant impacts can remove a significant fraction of the silicate mantle of a chondritic proto-Mercury and form the iron rich present-day Mercury. However, such high-temperature giant impacts seem at odds with the retainment of moderately volatile elements on present-day Mercury (Peplowski et al. 2011). We simulated a series of hyperbolic encounters between proto-Mercury and proto-Venus, which may occur in the chaotic early solar system. Tidal disruption of proto-Mercury always removes part of its silicate mantle while its iron core remains intact. We find, in favourable cases, four close encounters with fast spinning projectiles (resulting from previous encounters) can lead to present-day Mercury iron fraction. More encounters are needed when the spin and orbital angular momentum are not always aligned. These hyperbolic encounters have various outcomes, such as orbital decay, binary planets and change of spin rates. These results suggest the importance of proper treatment of close encounters in N-body simulations of planetary accretion.

[22]  arXiv:1912.05221 [pdf, other]

Title: Search for galactic Pevatron candidates in a population of unidentified gamma-ray sources

Authors: Gerrit Spengler

Comments: Accepted for publication in Astronomy & Astrophysics

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Experiment (hep-ex)

Lower limits on the energy cutoff for unidentified gamma-ray sources detected in the HESS galactic plane survey are derived. Additional public data from the VERITAS, HESS and Milagro experiments are used for MGRO J1908+06 to confirm the limit derived from the HESS galactic plane survey data and to enable further conclusions on the presence of spectral breaks. Five Pevatron candidates are identified in the HESS galactic plane survey. The cutoff of the gamma-ray spectrum for these sources is larger than 20 TeV at 90% confidence level. The gamma-ray sources MGRO J1908+06 and HESS J1641-463, found to be Pevatron candidates in the analysis of the HESS galactic plane survey catalog, had been discussed as Pevatron candidates before. For MGRO J1908+06, the lower limit on the gamma-ray energy cutoff is 30 TeV at 90% confidence level. This is a factor of almost two larger than previous results. Additionally, a break in the gamma-ray spectrum at energies between 1 TeV and 10 TeV with an index change larger than 0.5 can be excluded at 90% confidence level for MGRO J1908+06. The energy cutoff of accelerated particles is larger than 100 TeV at 90% confidence level in a hadronic scenario for all five Pevatron candidates. A hadronic scenario is plausible for at least three of the Pevatron candidates, based on the presence of nearby molecular clouds and supernova remnants.

[23]  arXiv:1912.05242 [pdf, other]

Title: The isothermal evolution of a shock-filament interaction

Authors: K. J. A. Goldsmith, J. M. Pittard

Comments: 21 pages, 26 figures

Subjects: Astrophysics of Galaxies (astro-ph.GA)

Studies of filamentary structures that are prevalent throughout the interstellar medium are of great significance to a number of astrophysical fields. Here, we present 3D hydrodynamic simulations of shock-filament interactions where the equation of state has been softened to become almost isothermal. We investigate the effect of such an isothermal regime on the interaction (where both the shock and filament are isothermal), and we examine how the nature of the interaction changes when the orientation of the filament, the shock Mach number, and the filament density contrast are varied. We find that only sideways-oriented filaments with a density contrast of $10^2$ form a three-rolled structure, dissimilar to the results of a previous study. Moreover, the angle of orientation of the filament plays a large role in the evolution of the filament morphology: the greater the angle of orientation, the longer and less turbulent the wake. Turbulent stripping of filament material leading to fragmentation of the core occurs in most filaments; however, filaments orientated at an angle of $85^{\circ}$ to the shock front do not fragment and are longer-lived. In addition, values of the drag time are influenced by the filament length, with longer filaments being accelerated faster than shorter ones. Furthermore, filaments in an isothermal regime exhibit faster acceleration than those struck by an adiabatic shock. Finally, we find that the drag and mixing times of the filament increase as the angle of orientation of the filament is increased.

[24]  arXiv:1912.05268 [pdf, other]

Title: Triaxiality can explain the alleged dark matter deficiency in some dwarf galaxies

Authors: J. Sanchez Almeida (1, 2), M. Filho (3, 4) ((1) Instituto de Astrofisica de Canarias, La Laguna, Spain, (2) Universidad de La Laguna, (3) Faculty of Engineering, University Oporto, Oporto, Portugal, (4) CENTRA/SIM, Faculty of Sciences, University Lisbon, Lisbon, Portugal)

Comments: To appear as a RNAAS

Subjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)

Dark Matter (DM) is an ingredient essential to the current cosmological concordance model. It provides the gravitational pull needed for the baryons to form galaxies. Therefore, the existence of galaxies without DM is both disquieting and extremely interesting. Guo et al. recently presented "further evidence for a population of DM-deficient dwarf galaxies", however, their analysis bypasses the triaxiality of the dwarf galaxies. We carry out a Monte Carlo simulation showing how triaxiality must be considered to measure dynamical masses from projected axial ratios, calling into question the evidence for a population of DM-deficient dwarf galaxies. Such a population may consist of normal almost face-on HI disks with their inclination overestimated.

[25]  arXiv:1912.05269 [pdf, other]

Title: Estimating Statistical Uncertainties of Internal Kinematics of Galaxies and Star Clusters Derived Using Full Spectrum Fitting

Authors: Igor V. Chilingarian, Kirill A. Grishin

Comments: 8 pages, 2 figures, submitted to PASP; the code is available here this https URL

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Astrophysics of Galaxies (astro-ph.GA)

Pixel-space full spectrum fitting exploiting non-linear $\chi^2$ minimization became a \emph{de facto} standard way of deriving internal kinematics from absorption line spectra of galaxies and star clusters. However, reliable estimation of uncertainties for kinematic parameters remains a challenge and is usually addressed by running computationally expensive Monte-Carlo simulations. Here we derive simple formulae for the radial velocity and velocity dispersion uncertainties based solely on the shape of a template spectrum used in the fitting procedure and signal-to-noise information. Comparison with Monte-Carlo simulations provides perfect agreement for different templates, signal-to-noise ratios and velocity dispersion between 0.5 and 10 times of the instrumental spectral resolution. We provide {\sc IDL} and {\sc python} implementations of our approach. The main applications are: (i) exposure time calculators; (ii) design of observational programs and estimates on expected uncertainties for spectral surveys of galaxies and star clusters; (iii) a cheap and accurate substitute for Monte-Carlo simulations when running them for large samples of thousands of spectra is unfeasible or when uncertainties reported by a non-linear minimization algorithms are not considered reliable.

[26]  arXiv:1912.05290 [pdf, other]

Title: The Single Star Path to Be Stars

Authors: Ben Hastings, Chen Wang, Norbert Langer

Comments: in press

Subjects: Solar and Stellar Astrophysics (astro-ph.SR)

Be stars are rapidly rotating B main sequence stars, which show line emission due to an outflowing disc. By studying the evolution of rotating single star models, we can assess their contribution to the observed Be star populations.
We identify the main effects which are responsible for single stars to approach critical rotation as functions of initial mass and metallicity, and predict the properties of populations of rotating single stars.
We perform population synthesis with single star models of initial masses ranging between 3 and 30 solar masses, initial equatorial rotation velocities between 0 and 600 kms$^{-1}$ at compositions representing the Milky Way, Large and Small Magellanic Clouds. These models include efficient core-envelope coupling mediated by internal magnetic fields and correspond to the maximum efficiency of Be star production. We predict Be star fractions and the positions of fast rotating stars in the colour-magnitude diagram.
We identify stellar wind mass-loss and the convective core mass fraction as the key parameters which determine the time dependance of the stellar rotation rates. Using empirical distributions of initial rotational velocities,our single star models can reproduce the trends observed in Be star fractions with mass and metallicity. However,they fail to produce a significant number of stars rotating very close to critical. We also find that rapidly rotating Be stars in the Magellanic Clouds should have significant surface nitrogen enrichments, which may be in conflict with abundance determinations of Be stars.
Single star evolution may explain the high number of Be stars if 70 to 80% of critical rotationwould be sufficient to produce the Be phenomenon. However even in this case, the unexplained presence of many Be stars far below the cluster turn-off indicates the importance of the binary channel for Be star production.

[27]  arXiv:1912.05296 [pdf, ps, other]

Title: Search for dark matter towards the Galactic Centre with 11 years of ANTARES data

Authors: The ANTARES Collaboration

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

Neutrino detectors participate in the indirect search for the fundamental constituents of dark matter (DM) in form of weakly interacting massive particles (WIMPs). In WIMP scenarios, candidate DM particles can pair-annihilate into Standard Model products, yielding considerable fluxes of high-energy neutrinos. A detector like ANTARES, located in the Northern Hemisphere, is able to perform a competitive search looking towards the Galactic Centre, where a high density of dark matter is thought to accumulate. Both this directional information and the spectral features of annihilating DM pairs are entered into an unbinned likelihood method to scan the data set in search for DM-like signals in ANTARES data. Results obtained upon unblinding 11 years of data are presented. A non-observation of dark matter is converted into limits on the velocity-averaged cross section for WIMP pair annihilation.

[28]  arXiv:1912.05299 [pdf, other]

Title: Diffusive shock acceleration and the resulting non-thermal emission from colliding-wind binary systems

Authors: J. M. Pittard, G. S. Vila, G. E. Romero

Comments: 14 pages, 20 figures, submitted to MNRAS

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)

We present a new model for the non-thermal emission from a colliding-wind binary. Relativistic protons and electrons are assumed to be accelerated through diffusive shock acceleration at the global shocks bounding the wind-wind collision region. The non-thermal particles that flow downstream from the shocks are subject to various cooling processes. We carefully resolve this cooling and calculate the anisotropic inverse Compton and relativistic bremsstrahlung emission from electrons, and the $\pi^{0}$-decay emission from the collision of non-thermal and thermal protons. We explore how the non-thermal emission changes with the stellar separation and the viewing angle of the system, and with the momentum ratio of the winds. In future work we will apply our model to real systems.

[29]  arXiv:1912.05309 [pdf, other]

Title: Testing CIBER cosmic infrared background measurements and axionlike particles with observations of TeV blazars

Authors: G. B. Long, W. P. Lin, P. H. T. Tam, W. S. Zhu

Comments: 15 pages, 5 figure, Accepted for publication in PRD

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA)

The first measurements from the CIBER experiment of extragalactic background light (EBL) in near-infrared (NIR) band exhibit a higher intensity than those inferred through $\gamma$-ray observations. Recent theoretical-EBL intensities are typically consistent with the very high energy (VHE) $\gamma$-ray observations. Yet, it is possible that the excess NIR radiation is a new component of EBL and not in tension with the TeV spectra of distant blazars, since the hypothetical axion-like particle (ALP) may lead to a reduced opacity of the Universe for VHE $\gamma$-rays. In order to probe whether the excess component arises mainly from EBL, thirteen observed spectra in high energy and VHE ranges from ten distant TeV BL Lac objects are fitted by four theoretical spectra which involve theoretical EBL (Gilmore ), Gilmore's EBL model including photon/ALP coupling, Gilmore's EBL with CIBER excess and the latter including photon/ALP coupling respectively. We find the goodness of fit for the model with CIBER excess can be improved with a significance of $7.6~\sigma$ after including the photon/ALP coupling; Thus, the ALP/photon mixing mechanism can effectively alleviate the tension; However, the Gilmore EBL model, on the whole, is more compatible with the observed spectra compared to those with ALP, although individual blazars such as PKS 1424+240 and 1ES 1101-232 prefer the ALP-model. Our results suggest that the recent EBL models can solely explain the VHE $\gamma$-ray observations, and assuming the existence of the ALP to alleviate the tension is not required in a statistical sense, thus the excess over the EBL models is less likely to be a new EBL component.

[30]  arXiv:1912.05310 [pdf, other]

Title: The first high-redshift changing-look quasars

Authors: Nicholas P. Ross, Matthew J. Graham, Giorgio Calderone, K. E. Saavik Ford, Barry McKernan, Daniel Stern

Comments: 12 pages, 7 figures, 4 tables. All data, analysis code and text are fully available at: github.com/d80b2t/CIV_CLQs. Comments, questions and suggestions welcome and encouraged

Subjects: Astrophysics of Galaxies (astro-ph.GA)

We report on three redshift $z>2$ quasars with dramatic changes in their C IV emission lines, the first sample of changing-look quasars (CLQs) at high redshift. This is also the first time the changing-look behaviour has been seen in a high-ionisation emission line. SDSS J1205+3422, J1638+2827, and J2228+2201 show interesting behaviour in their observed optical light curves, and subsequent spectroscopy shows significant changes in the C IV broad emission line, with both line collapse and emergence being displayed on rest-frame timescales of $\sim$240-1640 days. These are rapid changes, especially when considering virial black hole mass estimates of $M_{\rm BH} > 10^{9} M_{\odot}$ for all three quasars. Continuum and emission line measurements from the three quasars show changes in the continuum-equivalent width plane with the CLQs seen to be on the edge of the full population distribution, and showing indications of an intrinsic Baldwin effect. We put these observations in context with recent state-change models, and note that even in their observed low-state, the C IV CLQs are generally above $\sim$5\% in Eddington luminosity.

[31]  arXiv:1912.05316 [pdf, other]

Title: Success of Machine Learning algorithms in Dynamical Mass Measurements of Galaxy Clusters

Authors: Muhammad Haider Abbas

Comments: 14 pages, 3 figures

Subjects: Astrophysics of Galaxies (astro-ph.GA); Instrumentation and Methods for Astrophysics (astro-ph.IM)

In recent years, machine learning (ML) algorithms have been successfully employed in Astronomy for analyzing and interpreting the data collected from various surveys. The need for new robust and efficient data analysis tools in Astronomy is imminently growing as we enter the new decade. Astronomical data sets are growing both in size and complexity at an exponential rate and ML methodologies can revolutionize our ability to interpret observations and provide new means of discovery. In this essay we focus on recent success of ML algorithms in predicting the dynamical mass of galaxy clusters. We discuss the results of the study performed by Ho et al. [1] and their implications, where it was found that ML algorithms outperform conventional statistical methods and can offer a robust and accurate tool for dynamical mass estimation.

[32]  arXiv:1912.05318 [pdf, other]

Title: Searching for water ice in the coma of interstellar object 2I/Borisov

Authors: Bin Yang, Michael S. P. Kelley, Karen J. Meech, Jacqueline V. Keane, Silvia Protopapa, Schelte J. Bus

Comments: 5 pages, 4 figures, accepted for publication in A&A Letter

Subjects: Earth and Planetary Astrophysics (astro-ph.EP)

Interstellar Objects (ISO) passing through our Solar System offer a rare opportunity to probe the physical and chemical processes involved in solid body and planet formation in extrasolar systems. The main objective of our study is to search for diagnostic absorption features of water ice in the near infrared (NIR) spectrum of the second interstellar object 2I/2019 Q4 (Borisov) and compare its ice features to those of the Solar system icy objects. We observed 2I in the NIR on three separate occasions. The first observation was made on 2019 September 19 UT using the SpeX spectrograph at the 3-m IRTF and again on September 24 UT with the GNIRS spectrograph at the 8-m GEMINI telescope and the last observation was made on October 09 UT with IRTF. The spectra obtained from all three nights appear featureless. No absorption features associated with water ice are detected. Spectral modeling suggests that water grains, if present, comprise no more than 10% of the coma cross-section. The comet consistently exhibits a red D-type like spectrum with a spectral slope of about 6% per 100nm, which is similar to that of 1I/'Oumuamua and is comparable to Solar system comets.

[33]  arXiv:1912.05340 [pdf, ps, other]

Title: INAF Trieste Astronomical Observatory Information Technology Framework

Authors: S. Bertocco, D. Goz, L. Tornatore, A. Ragagnin, G. Maggio, F. Gasparo, C. Vuerli, G. Taffoni, M. Molinaro

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)

INAF Trieste Astronomical Observatory (OATs) has a long tradition in information technology applied to Astronomical and Astrophysical use cases, particularly for what regards computing for data reduction, analysis and simulations; data and archives management; space missions data processing; design and software development for ground-based instruments. The ensemble of these activities, in the last years, pushed the need to acquire new computing resources and technologies and to deep competences in theirs management. In this paper we describe INAF-OATs computing centre technological stuff, our involvement in different EU Projects both in the path of building of EOSC, the European Open Science Cloud; in the design and prototyping of new Exascale supercomputers in Europe and the main research activities carried on using our computing centre.

[34]  arXiv:1912.05343 [pdf, other]

Title: Spectroscopic characterization of nine binary star systems as well as HIP107136 and HIP107533

Authors: T. Heyne, M. Mugrauer, R. Bischoff, D. Wagner, S. Hoffmann, O. Lux, V. Munz, M. Geymeier, R. Neuhäuser

Comments: accepted for publication in AN, 16 pages, 5 figures, 16 tables

Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Earth and Planetary Astrophysics (astro-ph.EP)

We present the results of our 2nd radial velocity monitoring campaign, carried out with the \'Echelle spectrograph FLECHAS at the University Observatory Jena in the course of the Gro{\ss}schwabhausen binary survey between December 2016 and June 2018. The aim of this project is to obtain precise radial velocity measurements for spectroscopic binary stars in order to redetermine, verify, improve and constrain their Keplerian orbital solutions. In this paper we describe the observations, data reduction and analysis and present the results of this project. In total, we have taken 721 RV measurements of 11 stars and derived well determined orbital solutions for 9 systems (7 single-, and 2 double-lined spectroscopic binaries) with periods in the range between 2 and 70 days. In addition, we could rule out the orbital solutions for the previously classified spectroscopic binary systems HIP107136 and HIP107533, whose radial velocities are found to be constant on the km/s-level over a span of time of more than 500 days. In the case of HIP2225 a significant change of its systematic velocity is detected between our individual observing epochs, indicating the presence of an additional companion, which is located on a wider orbit in this system.

[35]  arXiv:1912.05352 [pdf, ps, other]

Title: Tracing the Dynamical Mass in Galaxy Disks Using HI Velocity Dispersion and its Implications for the Dark Matter Distribution in Galaxies

Authors: Mousumi Das, Stacy McGaugh, Roger Ianjamasimanana, James Schombert, K.S.Dwarakanath

Comments: 13 pages, 4 figures and 2 tables. To appear in ApJ

Subjects: Astrophysics of Galaxies (astro-ph.GA)

We present a method to derive the dynamical mass of face-on galaxy disks using their neutral hydrogen (HI) velocity dispersion. We have applied the method to nearby, gas rich galaxies that have extended HI gas disks and have low inclinations. The galaxy sample includes 4 large disk galaxies; NGC628, NGC6496, NGC3184, NGC4214 and 3 dwarf galaxies DDO46, DDO63 and DDO187. We have used archival data from the THINGS and LITTLE THINGS surveys to derive the HI gas distributions and SPITZER mid-infrared images to determine the stellar disk mass distributions. We examine the disk dynamical and baryonic mass ratios in the extreme outer disks where there is HI gas but no visible stellar disk. We find that for the large galaxies the disk dynamical and Hi gas mass surface densities are comparable in the outer disks. But in the smaller dwarf galaxies, for which the total HI gas mass dominates the baryonic mass i.e. M(HI)>M(stars), the disk dynamical mass is much larger than the baryonic mass. For these galaxies there must either be a very low luminosity stellar disk which provides the vertical support for the HI gas disk or there is halo dark matter associated with their disks, which is possible if the halo has an oblate shape so that the inner part of the dark matter halo is concentrated around the disk. Our results are important for explaining the equilibrium of HI disks in the absence of stellar disks, and is especially important for gas rich, dwarf galaxies that appear to have significant dark matter masses associated with their disks.

[36]  arXiv:1912.05369 [pdf, ps, other]

Title: Relativistic ocean $r$-modes during type-I X-ray bursts

Authors: Frank R. N. Chambers, Anna L. Watts

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

Accreting neutron stars (NS) can exhibit high frequency modulations in their lightcurves during thermonuclear X-ray bursts, known as burst oscillations. These frequencies can be offset from the NS spin frequency by several Hz (where known independently) and can drift by 1-3 Hz. One plausible explanation is that a wave is present in the bursting ocean, the rotating frame frequency of which is the offset. The frequency of the wave should decrease (in the rotating frame) as the burst cools hence explaining the drift. A strong candidate is a buoyant $r$-mode. To date, models that calculated the frequency of this mode taking into account the radial structure neglected relativistic effects and predicted rotating frame frequencies of $\sim$ 4 Hz and frequency drifts of > 5 Hz; too large to be consistent with observations. We present a calculation that includes frame-dragging and gravitational redshift that reduces the rotating frame frequency by up to 30 % and frequency drift by up to 20 %. Updating previous models for the ocean cooling in the aftermath of the burst to a model more representative of detailed calculations of thermonuclear X-ray bursts reduces the frequency of the mode still further. This model, combined with relativistic effects, can reduce the rotating frequency of the mode to $\sim$ 2 Hz and frequency drift to $\sim$ 2 Hz, which is closer to the observed values.

[37]  arXiv:1912.05380 [pdf, ps, other]

Title: The Comptonising medium of the neutron star in 4U 1636-53 through its lower kilohertz Quasi-Periodic Oscillations

Authors: Konstantinos Karpouzas, Mariano Méndez, Evandro M. Ribeiro, Diego Altamirano, Omer Blaes, Federico García

Comments: 20 pages, 9 figures

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

Inverse Compton scattering dominates the high energy part of the spectra of neutron star (NS) low mass X-ray binaries (LMXBs). It has been proposed that inverse Compton scattering also drives the radiative properties of kilohertz quasi periodic oscillations (kHz QPOs). In this work, we construct a model that predicts the energy dependence of the rms amplitude and time lag of the kHz QPOs. Using this model, we fit the rms amplitude and time lag energy spectra of the lower kHz QPO in the NS LMXB 4U 1636-53 over 11 frequency intervals of the QPO and report three important findings: (i) A medium that extends 1-8 km above the NS surface is required to fit the data; this medium can be sustained by the balance between gravity and radiation pressure, without forcing any equilibrium condition. (ii) We predict a time delay between the oscillating NS temperature, due to feedback, and the oscillating electron temperature of the medium which, with the help of phase resolved spectroscopy, can be used as a probe of the geometry and the feedback mechanism. (iii) We show that the observed variability as a function of QPO frequency is mainly driven by the oscillating electron temperature of the medium. This provides strong evidence that the Comptonising medium in LMXBs significantly affects, if not completely drives, the radiative properties of the lower kHz QPOs regardless of the nature of the dynamical mechanism that produces the QPO frequencies.

[38]  arXiv:1912.05392 [pdf, other]

Title: Climate bistability of Earth-like exoplanets

Authors: Murante G., Provenzale A., Vladilo G., Taffoni G., Silv L., Palazzi E., Hardenberg J., Maris M., Londero E., Knapic C., Zorba S

Comments: 14 pages, 7 figures, accepted for publication in MNRAS

Subjects: Earth and Planetary Astrophysics (astro-ph.EP)

Before about 500 million years ago, most probably our planet experienced temporary snowball conditions, with continental and sea ices covering a large fraction of its surface. This points to a potential bistability of Earth's climate, that can have at least two different (statistical) equilibrium states for the same external forcing (i.e., solar radiation). Here we explore the probability of finding bistable climates in earth-like exoplanets, and consider the properties of planetary climates obtained by varying the semi-major orbital axis (thus, received stellar radiation), eccentricity and obliquity, and atmospheric pressure. To this goal, we use the Earth-like planet surface temperature model (ESTM), an extension of 1D Energy Balance Models developed to provide a numerically efficient climate estimator for parameter sensitivity studies and long climatic simulations. After verifying that the ESTM is able to reproduce Earth climate bistability, we identify the range of parameter space where climate bistability is detected. An intriguing result of the present work is that the planetary conditions that support climate bistability are remarkably similar to those required for the sustainance of complex, multicellular life on the planetary surface. The interpretation of this result deserves further investigation, given its relevance for the potential distribution of life in exoplanetary systems.

[39]  arXiv:1912.05398 [pdf, ps, other]

Title: Low energy core collapse supernovae in the frame of the jittering jets explosion mechanism

Authors: Roni Anna Gofman, Noam Soker

Comments: Will be submitted in a couple of days to allow comments by readers

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

We relate the pre-explosion binding energy of the ejecta of core-collapse supernovae (CCSNe) of stars with masses in the lower range of CCSNe and the location of the convection zones in the pre-collapse core of these stars, to explosion properties in the frame of the jittering jets explosion mechanism. Our main conclusion is that in the frame of the jittering jets explosion mechanism the remnant of a pulsar in these low energy CCSNe has some significance, in that the launching of jets by the newly born neutron star (NS) spins-up the NS and create a pulsar. We crudely estimated the period of the pulsars to be tens of milliseconds in these cases. The convective zones seed perturbations that lead to accretion of stochastic angular momentum that in turn is assumed to launch jittering jets in this explosion mechanism. We calculate the binding energy and the location of the convective zones with the stellar evolution code \textsc{mesa}. For the lowest stellar masses, we study, $M_{\rm ZAMS} \simeq 8.5-11 M_\odot$, the binding energy above the convective zones is low, and so is the expected explosion energy in the jittering jets explosion mechanism that works in a negative feedback cycle. The expected mass of the NS remnant is $M_{\rm NS} \approx 1.25M_\odot-1.6M_\odot$, even for these low energy CCSNe.

[40]  arXiv:1912.05399 [pdf, other]

Title: The exponential tail of inflationary fluctuations: consequences for primordial black holes

Authors: Jose María Ezquiaga, Juan García-Bellido, Vincent Vennin

Comments: 31 + 2 pages, 13 figures

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Theory (hep-th)

The curvature perturbations produced during an early era of inflation are known to have quasi-Gaussian distribution functions close to their maximum, where they are well constrained by measurements of the cosmic microwave background anisotropies and of the large-scale structures. In contrast, the tails of these distributions are poorly known, although this part is the relevant one for rare, extreme objects such as primordial black holes. We show that these tails are highly non-Gaussian, and cannot be described with standard non-Gaussian expansions, that are designed to approximate the distributions close to their maximum only. Using the stochastic-$\delta N$ formalism, we develop a generic framework to compute the tails, which are found to have an exponential, rather than Gaussian, decay. These exponential tails are inevitable, and do not require any non-minimal feature as they simply result from the quantum diffusion of the inflaton field along its potential. We apply our formalism to a few relevant single-field, slow-roll inflationary potentials, where our analytical treatment is confirmed by comparison with numerical results. We discuss the implications for the expected abundance of primordial black holes in these models, and highlight that it can differ from standard results by several orders of magnitude. In particular, we find that potentials with an inflection point overproduce primordial black holes, unless slow roll is violated.

[41]  arXiv:1912.05412 [pdf, other]

Title: RSM detection map for direct exoplanet detection in ADI sequences

Authors: Carl-Henrik Dahlqvist, Faustine Cantalloube, Olivier Absil

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Earth and Planetary Astrophysics (astro-ph.EP)

Beyond the choice of wavefront control systems or coronographs, advanced data processing methods play a crucial role in disentangling potential planetary signals from bright quasi-static speckles. Among these methods, angular differential imaging (ADI) for data sets obtained in pupil tracking mode (ADI sequences) is one of the foremost research avenues, considering the many observing programs performed with ADI-based techniques and the associated discoveries. Inspired by the field of econometrics, here we propose a new detection algorithm for ADI sequences, deriving from the regime-switching model first proposed in the 1980s. The proposed model is very versatile as it allows the use of PSF-subtracted data sets (residual cubes) provided by various ADI-based techniques, separately or together, to provide a single detection map. The temporal structure of the residual cubes is used for the detection as the model is fed with a concatenated series of pixel-wise time sequences. The algorithm provides a detection probability map by considering two possible regimes for concentric annuli, the first one accounting for the residual noise and the second one for the planetary signal in addition to the residual noise. The algorithm performance is tested on data sets from two instruments, VLT/NACO and VLT/SPHERE. The results show an overall better performance in the receiver operating characteristic space when compared with standard signal-to-noise-ratio maps for several state-of-the-art ADI-based post-processing algorithms.

[42]  arXiv:1912.05422 [pdf, other]

Title: The Nucleus of Interstellar Comet 2I/Borisov

Authors: David Jewitt, Man-To Hui, Yoonyoung Kim, Max Mutchler, Harold Weaver, Jessica Agarwal

Comments: 24 Pages, 5 Figures

Subjects: Earth and Planetary Astrophysics (astro-ph.EP)

We present high resolution imaging observations of interstellar comet 2I/Borisov (formerly C/2019 Q4) obtained using the Hubble Space Telescope. Scattering from the comet is dominated by a coma of large particles (characteristic size 0.1 mm) ejected anisotropically. Convolution modeling of the coma surface brightness profile sets a robust limit to the spherical-equivalent nucleus radius r_n < 0.5 km (geometric albedo 0.04 assumed). We obtain an independent constraint based on the non-gravitational acceleration of the nucleus, finding r_n > 0.2 km (nucleus density 500 kg/m3 assumed). The profile and the non-gravitational constraints cannot be simultaneously satisfied if density < 25 kg/m3; the nucleus of comet Borisov cannot be a low density fractal assemblage of the type proposed elsewhere for the nucleus of 1I/'Oumuamua. We show that the spin-up timescale to outgassing torques, even at the measured low production rates, is comparable to or shorter than the residence time in the Sun's water sublimation zone. The spin angular momentum of the nucleus should be changed significantly during the current solar fly-by. Lastly, we find that the differential interstellar size distribution in the 0.5 mm to 100 m size range can be represented by power laws with indices < 4 and that interstellar bodies of 100 m size scale strike Earth every one to two hundred million years.

[43]  arXiv:1912.05423 [pdf, ps, other]

Title: Chemical properties of two dense cores in a Planck Galactic Cold Clump G168.72-15.48

Authors: Mengyao Tang, J. X. Ge, Sheng-Li Qin, Tie Liu, Yuefang Wu, Kee-Tae Kim, Sheng-Yuan Liu, Chao Zhang, J. H. He, Bing-Gang Ju, Xinhe Fang

Subjects: Astrophysics of Galaxies (astro-ph.GA)

To deepen our understanding of the chemical properties of the Planck Galactic Cold Clump (PGCC) G168.72-15.48, we performed observations of nine molecular species, namely, \ce{c-C3H}, \ce{H2CO}, \ce{HC5N}, \ce{HC7N}, \ce{SO}, \ce{CCH}, \ce{N2H+}, \ce{CH3OH}, and \ce{CH3CCH}, toward two dense cores in PGCC G168.72-15.48 using the Tianma Radio Telescope and Purple Mountain Observatory Telescope. We detected \ce{c-C3H}, \ce{H2CO}, \ce{HC5N}, \ce{N2H+}, \ce{CCH}, and \ce{CH3OH} in both G168-H1 and G168-H2 cores, whereas \ce{HC7N} and \ce{CH3CCH} were detected only in G168-H1 and SO was detected only in G168-H2. Mapping observations reveal that the \ce{CCH}, \ce{N2H+}, \ce{CH3OH}, and \ce{CH3CCH} emissions are well coupled with the dust emission in G168-H1. Additionally, \ce{N2H+} exhibits an exceptionally weak emission in the denser and more evolved G168-H2 core, which may be attributed to the \ce{N2H+} depletion. We suggest that the \ce{N2H+} depletion in G168-H2 is dominated by \ce{N2} depletion, rather than the destruction by CO. The local thermodynamic equilibrium calculations indicate that the carbon-chain molecules of \ce{CCH}, \ce{HC5N}, \ce{HC7N}, and \ce{CH3CCH} are more abundant in the younger G168-H1 core. We found that starless core G168-H1 may have the properties of cold dark clouds based on its abundances of carbon-chain molecules. While, the prestellar core G168-H2 exhibits lower carbon-chain molecular abundances than the general cold dark clouds. With our gas-grain astrochemical model calculations, we attribute the observed chemical differences between G168-H1 and G168-H2 to their different gas densities and different evolutionary stages.

[44]  arXiv:1912.05429 [pdf, other]

Title: Cosmological-scale parity violation of galaxy spin patterns

Authors: Lior Shamir

Comments: To be submitted. Comments welcome

Subjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)

Spiral galaxies are unique astronomical objects in the sense that their visual appearance depends on the perspective of the observer. Since the spin patterns of spiral galaxies (clockwise or counterclockwise) are expected to be randomly distributed, in a sufficiently large universe no difference between clockwise and counterclockwise galaxies is expected. Here I test the spin pattern distribution of ~6.4*10^5 galaxies with spectra from SDSS DR14, and compare the number of clockwise and counterclockwise galaxies in different redshift and RA ranges. The comparison shows a statistically significant asymmetry between the number of clockwise and counterclockwise galaxies. The data also shows that the asymmetry between the number of clockwise and counterclockwise galaxies changes with the redshift. The parts of the sky in which asymmetry was observed also show photometric asymmetry between clockwise and counterclockwise galaxies. When normalizing the data such that the redshift distribution of clockwise galaxies is similar to the redhsift distribution of the counterclockwise galaxies, the photometric asymmetry is eliminated. However, when normalizing the two datasets by the magnitude, statistically significant differences in the redshift remain. These evidence suggest that the local universe, as seen from Earth, might violate the isotropy and homogeneity assumptions.

[45]  arXiv:1912.05444 [pdf, other]

Title: Distribution of the C statistic with applications to the sample mean of Poisson data

Authors: M. Bonamente

Comments: Journal of Applied Statistics, accepted

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Instrumentation and Methods for Astrophysics (astro-ph.IM)

The C statistics, also known as the Cash statistic, is often used in astronomy for the analysis of low-count Poisson data. One of the challenges of the C statistic is that its probability distribution, under the null hypothesis that the data follow a parent model, is not known exactly. Such distribution is needed for model testing, namely to determine the acceptability of models and then to determine confidence intervals of model parameters. This is in contrast with the accurate knowledge, for Gaussian data, of the $\chi^2$ statistic for any number of free parameters in the parent model.
This paper presents an effort towards improving our understanding of the C statistic by studying (a) the distribution of for a fully specified model, (b) the distribution of $C_{min}$ resulting from a maximum-likelihood fit to a simple one-parameter constant model, i.e., a model that represents the sample mean of $N$ Poisson measurements, and (c) the distribution of the associated $\Delta C$ statistic that is used for parameter estimation. The results confirm the expectation that, in the high-count limit, both statistics have the same mean and variance as a $\chi^2$ statistic with same number of degrees of freedom. It is also found that, in the low-count regime, the expectation of the C statistic can be substantially lower than for a $\chi^2$ distribution. These result have implications for hypothesis testing in the low-count Poisson regime that are also discussed in the paper.
The paper makes use of recent X-ray observations of the astronomical source PG 1116+215 to illustrate the application of the C statistic to Poisson data. These measurements are also used to identify biases in the use of the $\chi^2$ statistic for Poisson data, especially in the low-count regime.

[46]  arXiv:1912.05461 [pdf, other]

Title: Long term operation with the DarkSide-50 detector

Authors: N. Canci

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Experiment (hep-ex); Instrumentation and Detectors (physics.ins-det)

DarkSide is a staged experimental project based on radiopure argon aiming at direct dark matter detection. The DarkSide-50 (DS-50) detector is currently operating underground at the Gran Sasso National Laboratory. DS-50 detector is a dual-phase, 50 kg, liquid argon time-projection-chamber readout by 38 cryogenic PMTs (Hamamatsu R11065), surrounded by an active liquid scintillator veto and contained in a water Cherenkov detector acting as a muon veto. DS-50 has been been operating continuously since 2013, first with atmospheric argon and subsequently filled in 2015 with argon from an underground source, allowing a reduction of the Ar-39 isotope by more than a factor 1000. Features of the DS-50 detector are described, long term operations and stability are reported and its performances in scintillation light detection discussed. Results on dark matter searches obtained with DarkSide-50 detector are briefly reported.

[47]  arXiv:1912.05464 [pdf, other]

Title: Search for Eccentric Binary Neutron Star Mergers in the first and second observing runs of Advanced LIGO

Authors: Alexander H. Nitz, Amber Lenon, Duncan A. Brown

Comments: 7 pages, 3 figures, 1 table, supplemental materials at this https URL

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc)

We present a search for gravitational waves from merging binary neutron stars which have non-negligible eccentricity as they enter the LIGO observing band. We use the public Advanced LIGO data which covers the period from 2015 through 2017 and contains $\sim164$ days of LIGO-Hanford and LIGO-Livingston coincident observing time. The search was conducted using matched-filtering using the PyCBC toolkit. We find no significant binary neutron star candidates beyond GW170817, which has previously been reported by searches for binaries in circular orbits. We place a 90 \% upper limit of $\sim1700$ mergers $\textrm{Gpc}^{-3} \textrm{Yr}^{-1}$ for eccentricities $\lesssim 0.43$ at a dominant-mode gravitational-wave frequency of 10 Hz. The absence of a detection with these data is consistent with theoretical predictions of eccentric binary neutron star merger rates. Using our measured rate we estimate the sensitive volume of future gravitational-wave detectors and compare this to theoretical rate predictions. We find that, in the absence of a prior detection, the rate limits set by six months of Cosmic Explorer observations would constrain all current plausible models of eccentric binary neutron star formation.

[48]  arXiv:1912.05479 [pdf, ps, other]

Title: Spectroscopic Tomography: A First Weak Lensing Detection Using Spectroscopic Redshifts Only

Authors: Ian Dell'Antonio, Jubee Sohn, Margaret J. Geller, Jacqueline McCleary

Comments: 20 pages, 9 figures

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)

We describe the first spectroscopic tomographic (spectrotomographic) weak lensing measurement for a galaxy cluster based only on background galaxies with spectroscopically determined redshifts. We use the massive cluster A2029 to demonstrate the power of combining spectroscopy and lensing to obtain accurate masses and to overcome biases from contamination and photometric redshift errors. We detect the shear signal from the cluster at $>3.9 \sigma$. The shear signal scales with source redshift in a way that is consistent with the angular diameter distance ratio variation in a $\Lambda$CDM Universe. Furthermore, the amplitude of the measured signal is consistent with the X-ray mass. Upcoming spectroscopic instruments such as the Prime Focus Spectrograph on Subaru will permit spectrotomographic weak lensing measurements with S/N comparable to current photometric-redshift-based weak lensing measurements for hundreds of galaxy clusters. Thus, spectrotomography may enable sensitive cosmological constraints that complement and are independent of other measurement techniques.

[49]  arXiv:1912.05491 [pdf, other]

Title: Implications for cosmology from Ground-based Cosmic Microwave Background observations

Authors: Ke Wang, Qing-Guo Huang

Comments: 6 pages and 5 figures

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)

Cosmic Microwave Background (CMB) anisotropy encodes a lot of information about our Universe. In this paper we take the ground-based CMB observations (GCMB), including the South Pole Telescope (SPT), SPTpol, the Atacama Cosmology Telescope Polarimeter (ACTPol) and BICEP2/Keck Array, as a new probe to the CMB anisotropy independent of two satellite observations, i.e. Wilkinson Microwave Anisotropy Probe (WMAP) and Planck. The combination of current GCMB data is consistent with WMAP and Planck. In the spatially flat $\Lambda$CDM model, the Hubble constant is $H_0=70.07\pm 1.57$ km/s/Mpc at $68\%$ confidence level (CL). Combining with baryon acoustic oscillation (BAO) and the Pantheon sample of Type Ia supernovae (SN), we find that $H_0=68.43\pm 0.59$ km/s/Mpc ($68\%$ CL) in the spatially flat $\Lambda$CDM cosmology which has a tension with local measurement given by Riess et al. in 2019 at $3.6\sigma$ level, and $\Omega_k=-0.0023\pm0.0037$ and $N_{\rm{eff}}=2.88\pm 0.39$ ($68\%$ CL) in the extended cosmological models.

[50]  arXiv:1912.05505 [pdf, other]

Title: Multiband optical flux density and polarization microvariability study of optically bright blazars

Authors: Magdalena Pasierb, Arti Goyal, Michał Ostrowski, Łukasz Stawarz, Paul J. Wiita, Gopal-Krishna, Valeri M. Larionov, Daria A. Morozova, Ryosuke Itoh, Fahri Alicavus, Ahmet Erdem, Santosh Joshi, Staszek Zola, Georgy A. Borman, Tatiana S. Grishina, Evgenia N. Kopatskaya, Elena G.Larionova, Sergey S. Savchenko, Anna A. Nikiforova, Yulia V. Troitskaya, Ivan S. Troitsky, Hiroshi Akitaya, Miho Kawabata, Tatsuya Nakaoka

Comments: MNRAS accepted

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

We present the results of flux density, spectral index, and polarization intra-night monitoring studies of a sample of eight optically bright blazars, carried out by employing several small to moderate aperture (0.4\,m to 1.5\,m diameter) telescopes fitted with CCDs and polarimeters located in Europe, India, and Japan. The duty cycle of flux variability for the targets is found to be $\sim 45$ percent, similar to that reported in earlier studies. The computed two-point spectral indices are found to be between 0.65 to 1.87 for our sample, comprised of low- and intermediate frequency peaked blazars, with one exception; they are also found to be statistically variable for about half the instances where `confirmed' variability is detected in flux density. In the analysis of the spectral evolution of the targets on hourly timescale, a counter-clockwise loop (soft-lagging) is noted in the flux-spectral index plane on two occasions, and in one case a clear spectral flattening with the decreasing flux is observed. In our data set, we also observe a variety of flux-polarization degree variability patterns, including instances with a relatively straightforward anti-correlation, correlation, or counter-clockwise looping. These changes are typically reflected in the flux-polarization angle plane: the anti-correlation between the flux and polarization degree is accompanied by an anti-correlation between the polarization angle and flux, while the counter-clockwise flux-PD looping behaviour is accompanied by a clockwise looping in the flux-polarization angle representation. We discuss our findings in the framework of the internal shock scenario for blazar sources.

[51]  arXiv:1912.05527 [pdf, other]

Title: On the Radio Image of Relativistic Jets -- I. Internal Structure, Doppler Boosting, and Polarization Maps

Authors: A.V. Chernoglazov (1, 2, 3), V.S. Beskin (2, 3), V.I. Pariev (2) ((1) University of New Hampshire, (2) P.N. Lebedev Physical Institute, (3) Moscow Institute of Physics and Technology)

Comments: 10 pages, 10 figures, published in MNRAS

Journal-ref: MNRAS, v. 488, 2019, p. 224-233

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

In this first paper from forthcoming series of works devoted to radio image of relativistic jets from active galactic nuclei the role of internal structure of a flow is discussed. We determine the radial profiles of all physical values for reasonable Michel magnetization parameter $\sigma_{\rm M}$ and ambient pressure $P_{\rm ext}$. Maps of Doppler boosting factor $\delta$ and observed directions of linear polarization of synchrotron emission are also constructed.

[52]  arXiv:1912.05528 [pdf, other]

Title: Evidence for cosmic acceleration with next-generation surveys: A model-independent approach

Authors: Carlos A. P. Bengaly

Comments: 5 pages, 4 figures. Comments welcome

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)

We quantify the evidence for cosmic acceleration using simulations of $H(z)$ measurements from SKA- and Euclid-like surveys. We perform a non-parametric reconstruction of the Hubble parameters and its derivative to obtain the deceleration parameter $q(z)$ using the Gaussian Processes method. This is a completely model-independent approach, so we can determine whether the Universe is undergoing accelerated expansion {\it regardless} of any assumption of a dark energy model. We find that Euclid-like and SKA-like band 1 surveys can probe cosmic acceleration at over $3$ and $5\sigma$ confidence level, respectively. Combining them with a SKA-like B2 survey, which reaches lower redshift ranges, the evidence for a current accelerated phase increases to over $7\sigma$. This is a significant improvement from current $H(z)$ measurements from cosmic chronometers and galaxy redshift surveys, showing that these surveys can underpin cosmic acceleration in a model-independent way.

Cross-lists for Thu, 12 Dec 19

[53]  arXiv:1910.05738 (cross-list from gr-qc) [pdf, other]

Title: Astro- and Quantum Physical Tests of Screened Scalar Fields

Authors: Christian Käding

Comments: PhD thesis; 140 pages

Subjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Theory (hep-th); Quantum Physics (quant-ph)

In general, modified gravity theories are modifications or extensions of Einstein's general relativity. Some of them give rise to additional scalar degrees of freedom in Nature. If these scalar fields exist and are light enough, they should cause a gravity-like fifth force that could, in principle, exceed gravity in its strength. However, there are tight constraints on fifth forces from Solar System-based tests. Screening mechanisms are popular means for avoiding these constraints by suppressing a fifth force in regions of high environmental mass density but allowing for phenomenologically interesting effects in environments of lower densities. In this thesis, scalar field models with screening mechanisms will be discussed and some astro- and quantum physical tests for their existence presented. At first, the impact of disformally coupled symmetrons on gravitational lensing by galaxies will be evaluated. Secondly, it will be shown how fluctuations of a chameleon scalar field induce the open dynamics of a quantum test particle. For this, tools from non-equilibrium quantum field theory will be introduced, developed and applied, and a quantum master equation derived.

[54]  arXiv:1912.05202 (cross-list from gr-qc) [pdf, ps, other]

Title: Stellar structure models in modified theories of gravity: lessons and challenges

Authors: Gonzalo J. Olmo, Diego Rubiera-Garcia, Aneta Wojnar

Comments: Review article, 88 pages. Comments and suggestions are welcome

Subjects: General Relativity and Quantum Cosmology (gr-qc); Solar and Stellar Astrophysics (astro-ph.SR); High Energy Physics - Theory (hep-th)

The understanding of stellar structure represents the crossroads of our theories of the nuclear force and the gravitational interaction under the most extreme conditions observably accessible. It provides a powerful probe of General Relativity on its strong field regime, and opens fruitful avenues for the exploration of new gravitational physics. The latter can be captured via the so-called modified theories of gravity. These theories typically change the Tolman-Oppenheimer-Volkoff equations of stellar's hydrostatic equilibrium, having a large impact on the astrophysical properties of the corresponding stars. For relativistic stars, such as neutron stars, the uncertainty on the equation of state of matter at supranuclear densities intertwines with the new parameters coming from the modified gravity side, providing a whole new phenomenology for the typical predictions of stellar structure models, such as mass-radius relations, maximum masses, or moment of inertia. For non-relativistic stars, the weakening/strengthening of the gravitational force inside astrophysical bodies via the modified Newtonian (Poisson) equation may induce changes on the star's mass, radius, central density or luminosity, having an impact, for instance, in the Chandrasekhar's limit for white dwarfs, or in the minimum mass for stable hydrogen burning for high-mass brown dwarfs. This work aims to provide a broad overview of the main such results achieved in the recent literature for many such modified theories of gravity, by combining the results and constraints obtained from the analysis of relativistic and non-relativistic stars in different scenarios. Moreover, we will build a bridge between the efforts of the community working on different theories, formulations, types of stars, theoretical modellings, and observational aspects, highlighting some of the most promising opportunities in the field.

[55]  arXiv:1912.05215 (cross-list from physics.plasm-ph) [pdf, other]

Title: Modeling imbalanced collisionless Alfvén wave turbulence with nonlinear diffusion equations

Authors: George Miloshevich, Thierry Passot, Pierre-Louis Sulem

Comments: 10 pages, 5 figures

Subjects: Plasma Physics (physics.plasm-ph); Solar and Stellar Astrophysics (astro-ph.SR); Space Physics (physics.space-ph)

A pair of nonlinear diffusion equations in Fourier space} is used to study the dynamics of strong Alfv\'en-wave turbulence, from MHD to electron scales. Special attention is paid to the regime of imbalance between the energies of counter-propagating waves commonly observed in the solar wind (SW), especially in regions relatively close to the Sun. In the collisionless regime where dispersive effects arise at scales comparable to or larger than those where dissipation becomes effective, the imbalance produced by a given injection rate of generalized cross-helicity (GCH), which is an invariant, is much larger than in the corresponding collisional regime described by the usual (or reduced) magnetohydrodynamics. The combined effect of high imbalance and ion Landau damping induces a steep energy spectrum for the transverse magnetic field at sub-ion scales. This spectrum is consistent with observations in highly Alfvenic regions of the SW, such as trailing edges, but does not take the form of a transition range continued at smaller scales by a shallower spectrum. This suggests that the observed spectra displaying such a transition result from the superposition of contributions originating from various streams with different degrees of imbalance. Furthermore, when imbalanced energy injection is supplemented at small scales in an already fully developed turbulence, for example under the effect of magnetic reconnection, a significant enhancement of the imbalance at all scales is observed.

[56]  arXiv:1912.05300 (cross-list from gr-qc) [pdf, ps, other]

Title: Black hole or Fuzz ball or a Loop quantum star ? Assessing the fate of a massive collapsing star

Authors: S. Kalyana Rama

Comments: Version 1. 17 pages

Subjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Theory (hep-th)

Using the effective equations in our Loop Quantum Cosmology (LQC) -- inspired models, we resolve the $(n + 2)$ dimensional black hole singularity. This resolution in the four dimensional case is same as that given recently by Ashtekar, Olmedo, and Singh. We then study the fate of a massive collapsing star in $(n + 2)$ dimensions, focussing on a singularity resolved black hole, a string theoretic fuzz ball, and a Loop quantum star -- which is a solution to the the effective modified equations for static spherically symmetric stars we obtained recently using LQC ideas. We find qualitatively that a massive collapsing star is likely to become a Loop quantum star : it is likely to have a macroscopic core region with Planckian densities and pressures which is surrounded by a low density corona region extending to the Schwarzschild radius.

[57]  arXiv:1912.05326 (cross-list from nucl-th) [pdf, other]

Title: Delineating the properties of neutron star matter in cold, dense QCD

Authors: Toru Kojo

Comments: 14 pages, 10 figures, talk given at 37th International Symposium on Lattice Field Theory - Lattice2019, 16-22 June 2019, Wuhan, China. arXiv admin note: text overlap with arXiv:1904.05080

Subjects: Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Lattice (hep-lat)

The properties of dense QCD matter are delineated through the construction of equations of state which should be consistent with the low and high density limits of QCD, nuclear laboratory experiments, and the neutron star observations. These constraints, together with the causality condition of the sound velocity, are used to develop the picture of hadron-quark continuity in which hadronic matter continuously transforms into quark matter (modulo small 1st order phase transitions). The resultant unified equation of state at zero temperature and $\beta$-equilibrium, which we call Quark-Hadron-Crossover (QHC19), is consistent with the measured properties of neutron stars as well as the microphysics known for the hadron phenomenology. In particular to $\sim 10n_0$ ($n_0$: saturation density) the gluons remain as non-perturbative as in vacuum and the strangeness can be as abundant as up- and down-quarks at the core of two-solar mass neutron stars. Within our modeling the maximum mass is found less than $\simeq 2.35$ times solar mass and the baryon density at the core ranges in $\sim 5$-8$n_0$.

[58]  arXiv:1912.05389 (cross-list from gr-qc) [pdf, other]

Title: Search for strongly lensed counterpart images of binary black hole mergers in the first two LIGO observing runs

Authors: Connor McIsaac, David Keitel, Thomas Collett, Ian Harry, Simone Mozzon, Oliver Edy, David Bacon

Comments: 5 pages + 7 pages in appendix. Comments welcome. Data release: this https URL

Subjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Astrophysical Phenomena (astro-ph.HE)

Strong gravitational lensing can produce multiple images of the same gravitational-wave signal, each arriving at different times and with different magnification factors. Previous work has explored if lensed pairs exist among the known high-significance events and found no evidence of this. However, the possibility remains that weaker counterparts of these events are present in the data, unrecovered by previous searches. We conduct a targeted search specifically looking for sub-threshold lensed images of known binary black hole (BBH) observations. We recover candidates matching three of the additional events first reported by Venumadhav et al. (2019), but find no evidence for additional BBH events. We also find no evidence that any of the Venumadhav et al. observations are lensed pairs. We demonstrate how this type of counterpart search can constrain hypotheses about the overall source and lens populations and we rule out at very high confidence the extreme hypothesis that all heavy BBH detections truly come from black holes with intrinsic masses < 15Msun at high redshift.

Replacements for Thu, 12 Dec 19

[59]  arXiv:1802.08255 (replaced) [pdf, other]

Title: Agama reference documentation

Authors: Eugene Vasiliev

Comments: The most up-to-date version of this document is always found on the GitHub page for Agama: this https URL; the arXiv version will be updated on major occasions. Additions in v2: new DF types, Schwarzschild modelling framework, etc

Journal-ref: https://ascl.net/1805.008 2018

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Astrophysics of Galaxies (astro-ph.GA)

[60]  arXiv:1805.06304 (replaced) [pdf]

Title: The dynamics of asteroid rotation, governed by YORP effect: the kinematic ansatz

Authors: Sergey V. Ershkov, Roman V. Shamin

Comments: 23 pages, 4 figures; Keywords: tidal dissipation, asteroid rotation, YORP effect; article is accepted for publication in "Acta Astronautica" (14 May 2018), DOI 10.1016/j.actaastro.2018.05.023

Journal-ref: Acta Astronautica 149, August 2018, Pages 47-54

Subjects: General Physics (physics.gen-ph); Earth and Planetary Astrophysics (astro-ph.EP)

[61]  arXiv:1810.10546 (replaced) [pdf, other]

Title: Scalaron-Higgs inflation

Authors: Anirudh Gundhi, Christian F. Steinwachs

Comments: References added, abstract changed, overall discussion improved, 31 pages (two-column layout), 18 figures; new subsection (VI C) added with precise conditions for a SM RG driven realization of the extremely small Higgs self-coupling scenario

Subjects: High Energy Physics - Theory (hep-th); Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc)

[62]  arXiv:1901.09573 (replaced) [pdf, other]

Title: Location, orbit and energy of a meteoroid impacting the moon during the Lunar Eclipse of January 21, 2019

Authors: Jorge I. Zuluaga (SEAP/IF/UdeA), Matipon Tangmatitham (MTU), Pablo A. Cuartas-Restrepo (SEAP/IF/UdeA), Jonathan Ospina (CAMO/SAA), Fritz Pichardo (ASTRODOM), Sergio A. Lopez (Astrosur/Orion/SAA), Karls Pena (ASTRODOM), J. Mauricio Gaviria-Posada (Obs.LaLoma)

Comments: 19 pages, 11 figures, 4 tables. Data and scripts available in this https URL Accepted for publication in MNRAS

Subjects: Earth and Planetary Astrophysics (astro-ph.EP)

[63]  arXiv:1902.09064 (replaced) [pdf, ps, other]

Title: Does spatial flatness forbid the turnaround epoch of collapsing structures?

Authors: Boudewijn F. Roukema, Jan J. Ostrowski

Comments: 38 pages; 9 figures; 6 tables; includes reproducibility script files, also available at this https URL ; v2: wording clarifications, discussion section substantially extended

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc)

[64]  arXiv:1903.06788 (replaced) [pdf, other]

Title: The Radio Scream from Black Holes at Cosmic Dawn: A Semi-Analytic Model for the Impact of Radio Loud Black-Holes on the 21 cm Global Signal

Authors: Aaron Ewall-Wice, Tzu-Ching Chang, T. Joseph W. Lazio

Comments: 21 pages. 15 figures. Accepted to MNRAS. Replacement matches accepted version

Subjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)

[65]  arXiv:1904.04842 (replaced) [pdf, other]

Title: Compact Binary Waveform Center-of-Mass Corrections

Authors: Charles J. Woodford, Michael Boyle, Harald P. Pfeiffer

Comments: 20 pages, 15 figures

Journal-ref: Phys. Rev. D 100, 124010 (2019)

Subjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Astrophysical Phenomena (astro-ph.HE)

[66]  arXiv:1905.04316 (replaced) [pdf, other]

Title: Searching for Dark Photon Dark Matter in LIGO O1 Data

Authors: Huai-Ke Guo, Keith Riles, Feng-Wei Yang, Yue Zhao

Comments: 8 pages, 4 figures

Journal-ref: Commun Phys 2, 155 (2019)

Subjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO)

[67]  arXiv:1905.12710 (replaced) [pdf, other]

Title: A cooling anomaly of high-mass white dwarfs

Authors: Sihao Cheng, Jeffrey D. Cummings, Brice Ménard

Comments: 18 pages, 11 figures; published in ApJ; discussions of double-WD merger rate have been moved to arxiv:1910.09558

Journal-ref: The Astrophysical Journal, Volume 886, Issue 2, article id. 100, 15 pp. (2019)

Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE)

[68]  arXiv:1906.03230 (replaced) [pdf, other]

Title: The M101 Satellite Luminosity Function and the Halo to Halo Scatter Among Local Volume Hosts

Authors: P. Bennet, D. J. Sand, D. Crnojević, K. Spekkens, A. Karunakaran, D. Zaritsky, B. Mutlu-Pakdil

Comments: 23 pages, 10 figures, accepted by ApJ

Journal-ref: 2019, ApJ, 885, 153

Subjects: Astrophysics of Galaxies (astro-ph.GA)

[69]  arXiv:1906.05406 (replaced) [pdf, ps, other]

Title: Can the quantum vacuum fluctuations really solve the cosmological constant problem?

Authors: Gabriel R. Bengochea, Gabriel León, Elias Okon, Daniel Sudarsky

Comments: 12 pages. Minor changes, comments added in Conclusions and new references. Accepted for publication in EPJC

Subjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO)

[70]  arXiv:1907.04938 (replaced) [pdf, other]

Title: Mini-EUSO data acquisition and control software

Authors: F. Capel, A. Belov, G. Cambiè, M. Casolino, C. Fornaro, P. Klimov, L. Marcelli, L. W. Piotrowski, S. Turriziani

Comments: Updated to match published version in JATIS. Code available at this https URL

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)

[71]  arXiv:1907.06669 (replaced) [pdf, other]

Title: Understanding Broad Mg II Variability in Quasars with Photoionization: Implications for Reverberation Mapping and Changing-Look Quasars

Authors: Hengxiao Guo (Illinois), Yue Shen (Illinois), Zhicheng He (USTC), Tinggui Wang (USTC), Xin Liu (Illinois), Shu Wang (KIAA), Mouyuan Sun (USTC), Qian Yang (Illinois), Minzhi Kong (HNU), Zhenfeng Sheng (USTC)

Comments: 15 pages, 10 figures, accepted for publication in ApJ

Subjects: Astrophysics of Galaxies (astro-ph.GA)

[72]  arXiv:1907.06676 (replaced) [pdf, other]

Title: Spectral Energy Distributions of Candidate Periodically-Variable Quasars: Testing the Binary Black Hole Hypothesis

Authors: Hengxiao Guo (Illinois), Xin Liu (Illinois), Zafar Tayyaba (AAO), Wei-Ting Liao (Illinois)

Comments: 14 pages, 10 figures, 2 tables, accepted for publication in MNRAS

Subjects: Astrophysics of Galaxies (astro-ph.GA)

[73]  arXiv:1907.12216 (replaced) [pdf, other]

Title: Coupled vector dark energy

Authors: Shintaro Nakamura, Ryotaro Kase, Shinji Tsujikawa

Comments: 18 pages, 3 figures, published version

Journal-ref: JCAP12(2019)032

Subjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Theory (hep-th)

[74]  arXiv:1908.00072 (replaced) [pdf, other]

Title: Discovery of A Mg II Changing-look AGN and its Implications for a Unification Sequence of Changing-look AGNs

Authors: Hengxiao Guo (Illinois), Mouyuan Sun (USTC), Xin Liu (Illinois), Tinggui Wang (USTC), Minzhi Kong (HNU), Shu Wang (KIAA), Zhenfeng Sheng (USTC), Zhicheng He (USTC)

Comments: 10 pages, 4 figures, 1 table, accepted for publication in ApJL

Journal-ref: The Astrophysical Journal Letters, Volume 883, Issue 2, article id. L44, 7 pp. (2019)

Subjects: Astrophysics of Galaxies (astro-ph.GA)

[75]  arXiv:1908.10873 (replaced) [pdf, ps, other]

Title: An empirical infrared transit spectrum of Earth: opacity windows and biosignatures

Authors: Evelyn J. R. Macdonald, Nicolas B. Cowan

Comments: 9 pages, 7 figures; updated figures 3, 6, and 7 to relabel the CO$_2$ feature at 2.7 $\mu$m; water vapour is more difficult to detect than originally stated

Journal-ref: Monthly Notices of the Royal Astronomical Society 489 (2019) 196-204

Subjects: Earth and Planetary Astrophysics (astro-ph.EP)

[76]  arXiv:1909.04735 (replaced) [pdf, other]

Title: Indirect effects of dark matter

Authors: K. M. Belotsky, E.A. Esipova, A.Kh. Kamaletdinov, E.S. Shlepkina, M.L. Solovyov

Comments: 20 pages, 14 figures

Journal-ref: International Journal of Modern Physics D, Volume 28, Issue 13, 1941011 (2019)

Subjects: High Energy Physics - Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE)

[77]  arXiv:1910.06945 (replaced) [pdf, other]

Title: Design and Performance of the first IceAct Demonstrator at the South Pole

Authors: M. G. Aartsen, M. Ackermann, J. Adams, J. A. Aguilar, M. Ahlers, M. Ahrens, C. Alispach, K. Andeen, T. Anderson, I. Ansseau, G. Anton, C. Argüelles, T. C. Arlen, J. Auffenberg, S. Axani, P. Backes, H. Bagherpour, X. Bai, A. Balagopal V., A. Barbano, I. Bartos, S. W. Barwick, B. Bastian, V. Baum, S. Baur, R. Bay, J. J. Beatty, K.-H. Becker, J. Becker Tjus, S. BenZvi, D. Berley, E. Bernardini, D. Z. Besson, G. Binder, D. Bindig, E. Blaufuss, S. Blot, C. Bohm, M. Bohmer, M. Börner, S. Böser, O. Botner, J. Böttcher, E. Bourbeau, J. Bourbeau, F. Bradascio, J. Braun, S. Bron, J. Brostean-Kaiser, A. Burgman, J. Buscher, R. S. Busse, T. Carver, C. Chen, E. Cheung, D. Chirkin, S. Choi, K. Clark, L. Classen, A. Coleman, G. H. Collin, J. M. Conrad, P. Coppin, P. Correa, D. F. Cowen, et al. (332 additional authors not shown)

Comments: Submitted to JINST

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); High Energy Astrophysical Phenomena (astro-ph.HE)

[78]  arXiv:1910.10516 (replaced) [pdf, other]

Title: Trans-Planckian censorship and other swampland bothers addressed in warm inflation

Authors: Arjun Berera, Jaime R. Calderón

Comments: 11 pages, 2 figures. In Press Physical Review D

Subjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Theory (hep-th)

[79]  arXiv:1911.01669 (replaced) [pdf, other]

Title: Relativistic stars in a cubic Galileon Universe

Authors: Hiromu Ogawa, Tsutomu Kobayashi, Kazuya Koyama

Comments: 8 pages, 3 figures. Accepted for publication in PRD

Subjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Theory (hep-th)

[80]  arXiv:1911.02819 (replaced) [pdf, other]

Title: New achievements in optical turbulence forecast systems in operational mode

Authors: E. Masciadri, Alessio Turchi, G. Martelloni (INAF-Osservatorio Astrofisico di Arcetri)

Comments: 8 figures, Proceedings of AO4ELT6 Conference, Quebec City 9-14 June 2019

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Atmospheric and Oceanic Physics (physics.ao-ph)

[81]  arXiv:1911.04201 (replaced) [pdf, ps, other]

Title: Neutron Star as Mirror for Gravitational Waves

Authors: Hao Wei, Da-Chun Qiang, Zhong-Xi Yu, Hua-Kai Deng

Comments: 6 pages, 3 figures, revtex4; v2: discussions added. arXiv admin note: text overlap with arXiv:1912.03466

Subjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Theory (hep-th)

[82]  arXiv:1911.04809 (replaced) [pdf, other]

Title: Slicing the cool circumgalactic medium along the major-axis of a star-forming galaxy at $z = 0.7$

Authors: S. Lopez, N. Tejos, L. F. Barrientos, C. Ledoux, K. Sharon, A. Katsianis, M. K. Florian, E. Rivera-Thorsen, M. B. Bayliss, H. Dahle, A. Fernandez-Figueroa, M. D. Gladders, M. Gronke, M. Hamel, I. Pessa, J. R. Rigby

Comments: Accepted for publication in MNRAS

Subjects: Astrophysics of Galaxies (astro-ph.GA)

[83]  arXiv:1912.01024 (replaced) [pdf, other]

Title: Toward the low-scatter selection of X-ray clusters: Galaxy cluster detection with eROSITA through cluster outskirts

Authors: Florian Käfer, Alexis Finoguenov, Dominique Eckert, Nicolas Clerc, Miriam E. Ramos-Ceja, Jeremy S. Sanders, Vittorio Ghirardini

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)

[84]  arXiv:1912.01550 (replaced) [pdf, ps, other]

Title: Supernovae Ia in 2019 (review): a rising demand for spherical explosions

Authors: Noam Soker (Technion, Israel)

Comments: A review paper. Updated, and then submitted, following valuable comments from readers

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)

[85]  arXiv:1912.02904 (replaced) [pdf, ps, other]

Title: The photon time delay in magnetized vacuum magnetosphere

Authors: A.W. Romero Jorge, E. Rodríguez Querts, H. Pérez Rojas, A. Pérez Martínez, L. Cruz Rodríguez, G. Piccinelli Bocchi, J. A. Rueda

Comments: 10 pages, 6 figures, and one appendix

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Phenomenology (hep-ph)

[86]  arXiv:1912.03933 (replaced) [pdf, ps, other]

Title: Comment on "Measurement of d + 7Be Cross Sections for Big-Bang Nucleosynthesis"

Authors: Alain Coc, Barry Davids

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)

[87]  arXiv:1912.04325 (replaced) [pdf, other]

Title: A model independent comparison of supernova and strong lensing cosmography: implications for the Hubble constant tension

Authors: Shivam Pandey, Marco Raveri, Bhuvnesh Jain

Comments: 13 pages, 11 figures, corrected typos and added references

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA)

[88]  arXiv:1912.04839 (replaced) [pdf, ps, other]

Title: Homogeneous Analysis of Globular Clusters from the APOGEE Survey with the BACCHUS Code. II. The Southern Clusters and Overview

Authors: Szabolcs Mészáros, Thomas Masseron, D. A. García-Hernández, Carlos Allende Prieto, Timothy C. Beers, Dmitry Bizyaev, Drew Chojnowski, Roger E. Cohen, Katia Cunha, Flavia Dell'Agli, Garrett Ebelke, José G. Fernández-Trincado, Peter Frinchaboy, Doug Geisler, Sten Hasselquist, Fred Hearty, Jon Holtzman, Jennifer Johnson, Richard R. Lane, Ivan Lacerna, Penelopé Longa-Peña, Steven R. Majewski, Sarah L. Martell, Dante Minniti, David Nataf, David L. Nidever, Kaike Pan, Ricardo P. Schiavon, Matthew Shetrone, Verne V. Smith, Jennifer S. Sobeck, Guy S. Stringfellow, László Szigeti, Baitian Tang, John C. Wilson, Olga Zamora

Comments: Accepted for publication in MNRAS, 31 pages, 24 figures, 7 tables. Updated version includes the correct iron scale used by Carretta et al. 2009, and referenced in Section 4.1

Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)

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