Astrophysics
New submissions
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New submissions for Mon, 2 Mar 20
- [1] arXiv:2002.12350 [pdf]
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Title: Coming of Age of the Standard ModelComments: Published in Nature Astronomy. Summary of the 10th Anniversary KICC ConferenceJournal-ref: Nat Astron 4, 122-123 (2020)Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
Cosmology now has a standard model - a remarkably simple description of the universe, its contents and its history. A symposium held last September in Cambridge, UK, gave this model a 'health check' and discussed fascinating questions that lie beyond it.
- [2] arXiv:2002.12368 [pdf, other]
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Title: Magnetohydrodynamic Non-linearities in Sunspot Atmospheres: Chromospheric Detections of Intermediate ShocksAuthors: S.J. Houston, D.B. Jess, R. Keppens, M. Stangalini, P.H. Keys, S.D.T. Grant, S. Jafarzadeh, L.M. McFetridge, M. Murabito, I. Ermolli, F. GiorgiComments: 17 pages, 9 figures, accepted by ApJSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
The formation of shocks within the solar atmosphere remains one of the few observable signatures of energy dissipation arising from the plethora of magnetohydrodynamic waves generated close to the solar surface. Active region observations offer exceptional views of wave behavior and its impact on the surrounding atmosphere. The stratified plasma gradients present in the lower solar atmosphere allow for the potential formation of many theorized shock phenomena. In this study, using chromospheric Ca II 854.2nm spectropolarimetric data of a large sunspot, we examine fluctuations in the plasma parameters in the aftermath of powerful shock events that demonstrate polarimetric reversals during their evolution. Modern inversion techniques are employed to uncover perturbations in the temperatures, line-of-sight velocities, and vector magnetic fields occurring across a range of optical depths synonymous with the shock formation. Classification of these non-linear signatures is carried out by comparing the observationally-derived slow, fast, and Alfv\'en shock solutions to the theoretical Rankine-Hugoniot relations. Employing over 200,000 independent measurements, we reveal that the Alfv\'en (intermediate) shock solution provides the closest match between theory and observations at optical depths of log(tau) = -4, consistent with a geometric height at the boundary between the upper photosphere and lower chromosphere. This work uncovers first-time evidence of the manifestation of chromospheric intermediate shocks in sunspot umbrae, providing a new method for the potential thermalization of wave energy in a range of magnetic structures, including pores, magnetic flux ropes, and magnetic bright points.
- [3] arXiv:2002.12369 [pdf, ps, other]
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Title: The Curious Case of PHL 293B: A Long-Lived Transient in a Metal-Poor Blue Compact Dwarf GalaxyAuthors: Colin J. Burke, Vivienne F. Baldassare, Xin Liu, Ryan J. Foley, Yue Shen, Antonella Palmese, Hengxiao Guo, K. Herner, A. R. Walker, A. A. Plazas, A. Carnero Rosell, B. Santiago, D. Gruen, D. Brooks, D. J. James, D. L. Hollowood, E. Krause, E. Bertin, E. Gaztanaga, E. Suchyta, E. Sanchez, F. Menanteau, F. Paz-Chinchon, G. Gutierrez, G. Tarle, I. Sevilla-Noarbe, J. Carretero, J. Frieman, J. De Vicente, J. Garcia-Bellido, J. Gschwend, K. Honscheid, K. Kuehn, L. N. da Costa, M. Soares-Santos, M. A. G. Maia, M. Smith, M. Carrasco Kind, M. Aguena, M. E. C. Swanson, P. Doel, R. Miquel, S. Allam, S. Avila, S. Serrano, S. Desai, S. Everett, T. N. Varga, T. F. Eifler, T. F. Eifler, V. Scarpine, DES CollaborationComments: 14 pages, 5 figures, 1 table. Submitted to ApJ Letters. Comments welcome!Subjects: Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE)
We report on small-amplitude optical variability and recent dissipation of the unusually persistent broad emission lines in the blue compact dwarf galaxy PHL 293B. The galaxy's unusual spectral features (P Cygni-like profiles with $\sim$800 km s$^{-1}$ blueshifted absorption lines) have resulted in conflicting interpretations of the nature of this source in the literature. However, analysis of new Gemini spectroscopy reveals the broad emission has begun to fade after being persistent for over a decade prior. Precise difference imaging light curves constructed with the Sloan Digital Sky Survey and the Dark Energy Survey reveal small-amplitude optical variability of $\sim$0.1 mag in the g band offset by $100\pm15$ pc from the brightest pixel of the host. The light curve is well-described by an active galactic nuclei (AGN)-like damped random walk process. However, we conclude that the origin of the optical variability and spectral features of PHL 293B is due to a long-lived stellar transient, likely a Type IIn supernova or non-terminal outburst, mimicking long-term AGN-like variability. This work highlights the challenges of discriminating between scenarios in such extreme environments, relevant to searches for AGNs in dwarf galaxies. This is the second long-lived transient discovered in a blue compact dwarf, after SDSS1133. Our result implies such long-lived stellar transients may be more common in metal-deficient galaxies. Systematic searches for low-level variability in dwarf galaxies will be possible with the upcoming Legacy Survey of Space and Time at Vera C. Rubin Observatory.
- [4] arXiv:2002.12370 [pdf, other]
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Title: Spurious Point Source Signals in the Galactic Center ExcessComments: 5+5 pages, 3+3 figures. Accompanying paper "The Enigmatic Galactic Center Excess: Spurious Point Sources and Signal Mismodeling" posted simultaneouslySubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Phenomenology (hep-ph)
We re-examine evidence that the Galactic Center Excess (GCE) originates primarily from point sources (PSs). We show that in our region of interest, non-Poissonian template fitting (NPTF) evidence for GCE PSs is an artifact of unmodeled north-south asymmetry of the GCE. This asymmetry is strongly favored by the fit (although it is unclear if this is physical), and when it is allowed, the preference for PSs becomes insignificant. We reproduce this behavior in simulations, including detailed properties of the spurious PS population. We conclude that NTPF evidence for GCE PSs is highly susceptible to certain systematic errors, and should not at present be taken to robustly disfavor a dominantly smooth GCE.
- [5] arXiv:2002.12371 [pdf, other]
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Title: The Enigmatic Galactic Center Excess: Spurious Point Sources and Signal MismodelingComments: 47 pages, 14 figures. Accompanying paper "Spurious Point Sources in the Galactic Center Excess" posted simultaneouslySubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Phenomenology (hep-ph)
The Galactic Center GeV excess (GCE) has garnered great interest as a possible signal of either dark matter annihilation or some novel astrophysical phenomenon, such as a new population of gamma-ray emitting pulsars. In a companion paper, we showed that in a $10^\circ$ radius region of interest (ROI) surrounding the Galactic Center, apparent evidence for GCE point sources (PSs) from non-Poissonian template fitting (NPTF) is actually an artifact of unmodeled north-south asymmetry of the GCE. In this work, we develop a simplified analytic description of how signal mismodeling can drive an apparent preference for a PS population, and demonstrate how the behavior pointed out in the companion paper also appears in simpler simulated datasets that contain no PS signals at all. We explore the generality of this behavior in the real gamma-ray data, and discuss the implications for past and future studies using NPTF techniques. While the drop in PS preference once north-south asymmetry is included is not ubiquitous in larger ROIs, we show that any overly-rigid signal model is expected to yield a spurious PS signal that can appear very convincing: as well as apparent significance comparable to what one would expect from a true PS population, the signal can exhibit stability against a range of variations in the analysis, and a source count function that is very consistent with previous apparent NPTF-based detections of a GCE PS population. This contrasts with previously-studied forms of systematic mismodeling which are unlikely to mimic a PS population in the same way. In the light of this observation, and its explicit realization in the region where the GCE is brightest, we argue that a dominantly smooth origin for the GCE is not in tension with existing NPTF analyses.
- [6] arXiv:2002.12373 [pdf, other]
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Title: Foreground Mismodeling and the Point Source Explanation of the Fermi Galactic Center ExcessAuthors: Malte Buschmann, Nicholas L. Rodd, Benjamin R. Safdi, Laura J. Chang, Siddharth Mishra-Sharma, Mariangela Lisanti, Oscar MaciasComments: 27 pages, 18 figures, comments welcomeSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Phenomenology (hep-ph)
The Fermi Large Area Telescope has observed an excess of ~GeV energy gamma rays from the center of the Milky Way, which may arise from near-thermal dark matter annihilation. Firmly establishing the dark matter origin for this excess is however complicated by challenges in modeling diffuse cosmic-ray foregrounds as well as unresolved astrophysical sources, such as millisecond pulsars. Non-Poissonian Template Fitting (NPTF) is one statistical technique that has previously been used to show that at least some fraction of the GeV excess is likely due to a population of dim point sources. These results were recently called into question by Leane and Slatyer (2019), who showed that a synthetic dark matter annihilation signal injected on top of the real Fermi data is not recovered by the NPTF procedure. In this work, we perform a dedicated study of the Fermi data and explicitly show that the central result of Leane and Slatyer (2019) is likely driven by the fact that their choice of model for the Galactic foreground emission does not provide a sufficiently good description of the data. We repeat the NPTF analyses using a state-of-the-art model for diffuse gamma-ray emission in the Milky Way and introduce a novel statistical procedure, based on spherical-harmonic marginalization, to provide an improved description of the Galactic diffuse emission in a data-driven fashion. With these improvements, we find that the NPTF results continue to robustly favor the interpretation that the Galactic Center excess is due, in part, to unresolved astrophysical point sources across the analysis variations that we have explored.
- [7] arXiv:2002.12375 [pdf, other]
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Title: TYCHO -- Realistically Simulating Exoplanets within Stellar Clusters I: Improving the Monte Carlo ApproachAuthors: Joseph P. Glaser, Stephen L.W. McMillan, Aaron M. Geller, Jonathan D. Thornton, Mark R. GiovinazziComments: 16 Pages, 9 Figures, 4 Tables; Submitted to ApJSubjects: Earth and Planetary Astrophysics (astro-ph.EP); Astrophysics of Galaxies (astro-ph.GA); Instrumentation and Methods for Astrophysics (astro-ph.IM); Solar and Stellar Astrophysics (astro-ph.SR)
To fully understand the diverse population of exoplanets, we must study their early lives within open clusters, the birthplace of most stars with masses $>0.5M_\odot$ (including those currently in the field). Indeed, when we observe planets within clustered environments, we notice highly eccentric and odd systems that suggest the importance of dynamical pathways created by interactions with additional bodies (as in the case of HD 285507b). However, it has proven difficult to investigate these effects, as many current numerical solvers for the multi-scale $N$-body problem are simplified and limited in scope. To remedy this, we aim to create a physically complete computational solution to explore the role of stellar close encounters and interplanetary interactions in producing the observed exoplanet populations for both open cluster stars and field stars. We present a new code, TYCHO, which employs a variety of different computational techniques, including multiple $N$-body integration methods, close encounter handling, modified Monte Carlo scattering experiments, and a variety of empirically informed initial conditions. We discuss the methodology in detail, and its implementation within the AMUSE software framework. Approximately 1$\%$ of our systems are promptly disrupted by star-star encounters contributing to the rogue planets occurrence rate. Additionally, we find that close encounters which perturb long-period planets lead to 38.3$\%$ of solar-system-like planetary systems becoming long-term unstable.
- [8] arXiv:2002.12378 [pdf, other]
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Title: Lyman Alpha Reference Sample: X. Predicting Lyman alpha output from starforming galaxies using multivariate regressionAuthors: Axel Runnholm, Matthew Hayes, Jens Melinder, Emil Rivera-Thorsen, Göran Östlin, John Cannon, Daniel KunthComments: Accepted for publication in ApJ. 23 pages, 6 figuresSubjects: Astrophysics of Galaxies (astro-ph.GA)
Understanding the production and escape of Lyman $\alpha$ (Ly$\alpha$) radiation from star-forming galaxies is a long standing problem in astrophysics. The ability to predict the Ly$\alpha$ luminosity of galaxies would open up new ways of exploring the Epoch of Reionization (EoR), and to estimate Ly$\alpha$ emission from galaxies in cosmological simulations where radiative transfer calculations cannot be done. We apply multivariate regression methods to the Lyman Alpha Reference Sample dataset to obtain a relation between the galaxy properties and the emitted Ly$\alpha$. The derived relation predicts the Ly$\alpha$ luminosity of our galaxy sample to good accuracy, regardless of whether we consider only direct observables (root-mean-square (RMS) dispersion around the relation of $\sim 0.19$ dex) or derived physical quantities (RMS $\sim 0.27$ dex). We confirm the predictive ability on a separate sample of compact star-forming galaxies and find that the prediction works well, but that aperture effects on measured Ly$\alpha$ luminosity may be important, depending on the redshift of the galaxy. We apply statistical feature selection techniques to determine an order of importance of the variables in our dataset, enabling future observations to be optimized for predictive ability. When using physical variables, we are able to determine that the most important predictive parameters are, in order, star formation rate, dust extinction, compactness and the gas covering fraction. We discuss the application of our results in terms of studying the EoR and intensity mapping experiments.
- [9] arXiv:2002.12380 [pdf, other]
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Title: Exploring the differences of integrated and spatially resolved analysis using integral field unit data: The case of Abell 14Authors: Stavros Akras, Hektor Monteiro, Isabel Aleman, Marcos A. F. Farias, D. May, Claudio B. PereiraComments: 16 pages, 11 figures, 3 tables. Accepted for publication in MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)
We present a new approach to study planetary nebulae using integral field spectroscopy. VLT@VIMOS datacube of the planetary nebula Abell 14 is analysed in three different ways by extracting: (i) the integrated spectrum, (ii) 1-dimensional simulated long slit spectra for different position angles and (iii) spaxel-by-spaxel spectra. These data are used to built emission-line diagnostic diagrams and explore the ionization structure and excitation mechanisms combining data from 1- and 3- dimensional photoionization models. The integrated and 1D simulated spectra are suitable for developing diagnostic diagrams, while the spaxel spectra can lead to misinterpretation of the observations. We find that the emission-line ratios of Abell 14 are consistent with UV photo-ionized emission, however there are some pieces of evidence of an additional thermal mechanism. The chemical abundances confirm its previous classification as a Type I planetary nebula, without spatial variation. We find, though, variation in the ionization correction factors (ICFs) as a function of the slit position angle. The star at the geometric centre of Abell 14 has an A5 spectral type with an effective temperature of Teff = 7909$\pm$135 K and surface gravity log(g) = 1.4$\pm$0.1 cm s$^{-2}$. Hence, this star cannot be responsible for the ionization state of the nebula. Gaia parallaxes of this star yield distances between 3.6 and 4.5 kpc in good agreement with the distance derived from a 3-dimensional photoionization modelling of Abell 14, indicating the presence of a binary system at the centre of the planetary nebula.
- [10] arXiv:2002.12382 [pdf, other]
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Title: No Evidence for Type Ia Supernova Luminosity Evolution: Evidence for Dark Energy is RobustAuthors: B. M. Rose, D. Rubin, A. Cikota, S. Deustua, S. Dixon, A. Fruchter, D. O. Jones, A. G. Riess, D. M. ScolnicComments: 12 pages, 5 figures, 3 tables. Submitted to ApJLSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA)
Type Ia Supernovae (SNe Ia) are powerful standardized candles for constraining the cosmological model and provided the first evidence of accelerated expansion. Their precision derives from empirical correlations now measured from $>1000$ SNe Ia between their luminosities, light curve shapes, colors and most recently a modest relationship with the mass of their host galaxy. As mass correlates with other host properties, these have been investigated to improve SN Ia standardization though none have been shown to significantly alter the determination of cosmological parameters. We re-examine a recent claim, based on 34 SN Ia in nearby passive host galaxies, of a 0.05 mag/Gyr dependence of standardized SN Ia luminosity on host age which if extrapolate to higher redshifts, might accrue to 0.25 mag challenging the inference of dark energy. We reanalyze this sample of hosts using both the original method and a Bayesian Hierarchical Model and find after a fuller accounting of the errors the significance for a dependence on age to be $\leq2\sigma$ and $\sim1\sigma$ after removal of a single poorly-measured SN. To test the claim that a trend seen in old stellar populations can be applied to younger ages, we extend our analysis to a larger sample which includes young hosts. We find the residual dependence of host age (after all standardization typically employed for cosmological measurements) to be $0.0011\pm0.0018$ mag/Gyr ($0.6\sigma$) for 254 SNe Ia from the Pantheon sample, consistent with no trend and strongly ruling out the large but low significance trend claimed from the passive hosts.
- [11] arXiv:2002.12383 [pdf, other]
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Title: The study of the angular and spatial distribution of radio selected AGNs and star-forming galaxies in the ELAIS N1 fieldComments: There are 13 pages, 9 figures and 2 tables. The paper is submitted on 25th January, 2020 and it is under review process. Any comments or suggestions are welcomeSubjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
The cosmic evolution of bias of different source populations with underlying dark matter density field in post reionization era can shed light on large scale structures. Studying the angular and spatial distribution of different compact sources using deep radio catalogue at low-frequency is essential to understand the matter distribution of the present Universe. Here, we investigate the relationship of luminous matter with their host dark matter haloes by measuring the angular and spatial clustering of sources (two-point statistics), using deep radio observation of ELAIS N1 (EN1) field with upgraded Giant Metrewave Radio Telescope (uGMRT) at 300-500 MHz. We also analyze the 612 MHz GMRT archival data of the same field to understand the cosmic evolution of clustering of different source populations. We classify the sources as star-forming galaxies (SFGs) and active galactic nuclei (AGN) based on their radio luminosity. We find that the spatial clustering length and bias to the dark matter density field of SFGs are smaller than AGNs at both frequencies. This proves that AGNs are mainly hosted by massive haloes and hence strongly clustered. However, a small decrease in the bias for both kind of sources at higher frequency indicates that we are most likely tracing the faint objects residing in less massive haloes at higher frequencies. Our results are in excellent agreement with previous findings at radio and multi-frequency surveys. However, comparison with SKADS simulation suggests that the halo mass for different populations used in the simulation is systematically lower. This work quantifies the spatial distribution of extragalactic compact objects in EN1 field.
- [12] arXiv:2002.12384 [pdf, other]
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Title: Intermittent hydrodynamic jets in collapsars do not produce GRBsSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
Strong variability is a common characteristic of the prompt emission of gamma-ray bursts (GRB). This observed variability is widely attributed to an intermittency of the central engine, through formation of strong internal shocks in the GRB-emitting jet expelled by the engine. In this paper we study numerically the propagation of hydrodynamic jets, injected periodically by a variable engine, through the envelope of a collapsed star. By post-processing the output of 3D numerical simulations, we compute the net radiative efficiency of the outflow. We find that all intermittent jets are subject to heavy baryon contamination that inhibits the emission at and above the photosphere well below detection limits. This is in contrast to continuous jets that, as shown recently, produce a highly variable gamma-ray photospheric emission with high efficiency, owing to the interaction of the jet with the stellar envelope. Our results challenge the variable engine model for hydrodynamic jets, and may impose constraints on the duty cycle of GRB engines. If such systems exist in nature, they are not expected to produce bright gamma-ray emission, but should appear as X-ray, optical and radio transients that resemble a delayed GRB afterglow signal.
- [13] arXiv:2002.12386 [pdf, other]
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Title: Imbalance Learning for Variable Star ClassificationComments: 11 pages, 8 figures, Accepted for publication in MNRASSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Machine Learning (cs.LG)
The accurate automated classification of variable stars into their respective sub-types is difficult. Machine learning based solutions often fall foul of the imbalanced learning problem, which causes poor generalisation performance in practice, especially on rare variable star sub-types. In previous work, we attempted to overcome such deficiencies via the development of a hierarchical machine learning classifier. This 'algorithm-level' approach to tackling imbalance, yielded promising results on Catalina Real-Time Survey (CRTS) data, outperforming the binary and multi-class classification schemes previously applied in this area. In this work, we attempt to further improve hierarchical classification performance by applying 'data-level' approaches to directly augment the training data so that they better describe under-represented classes. We apply and report results for three data augmentation methods in particular: $\textit{R}$andomly $\textit{A}$ugmented $\textit{S}$ampled $\textit{L}$ight curves from magnitude $\textit{E}$rror ($\texttt{RASLE}$), augmenting light curves with Gaussian Process modelling ($\texttt{GpFit}$) and the Synthetic Minority Over-sampling Technique ($\texttt{SMOTE}$). When combining the 'algorithm-level' (i.e. the hierarchical scheme) together with the 'data-level' approach, we further improve variable star classification accuracy by 1-4$\%$. We found that a higher classification rate is obtained when using $\texttt{GpFit}$ in the hierarchical model. Further improvement of the metric scores requires a better standard set of correctly identified variable stars and, perhaps enhanced features are needed.
- [14] arXiv:2002.12391 [pdf, ps, other]
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Title: Test the hypothesis of compact-binary-coalescence origin of fast radio bursts through a multi-messenger approachComments: 6 pages, 2 figures, accepted by APJLSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
In the literature, compact binary coalescences (CBCs) have been proposed as one of the main scenarios to explain the origin of some non-repeating fast radio bursts (FRBs). The large discrepancy between the FRB and CBC event rate densities suggest their associations, if any, should only apply at most for a small fraction of FRBs. Through a Bayesian estimation method, we show how a statistical analysis of the coincident associations of FRBs with CBC gravitational wave (GW) events may test the hypothesis of these associations. We show that during the operation period of advanced LIGO, the detection of $\sim100$ ($\sim1000$) GW-less FRBs with dispersion measure (DM) values smaller than 500 ${\rm pc~cm^{-3}}$ could reach the constraint that less than $10\%$ (or $1\%$) FRBs are related to binary black hole (BBH) mergers. The same number of FRBs with DM values smaller than 100 ${\rm pc~cm^{-3}}$ is required to reach the same constraint for binary neutron star (BNS) mergers. With the upgrade of GW detectors, the same constraints for BBH and BNS mergers can be reached with less FRBs or looser requirements for the DM values. It is also possible to pose constraints on the fraction of each type of CBCs that are able to produce observable FRBs based on the event density of FRBs and CBCs. This would further constrain the dimensionless charge of black holes in binary BH systems.
- [15] arXiv:2002.12437 [pdf, other]
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Title: Dusty Stellar Birth and Death in the Metal-Poor Galaxy NGC 6822Authors: Alec S. Hirschauer, Laurin Gray, Margaret Meixner, Olivia C. Jones, Sundar Srinivasan, Martha L. Boyer, B. A. SargentComments: Accepted for publication in The Astrophysical Journal; 27 pages, 13 figures, 12 tables (master catalog will be available from publisher)Subjects: Astrophysics of Galaxies (astro-ph.GA)
The nearby ($\sim$500 kpc) metal-poor ([Fe/H] $\approx$ -1.2; $Z$ $\approx$ 30% $Z_{\odot}$) star-forming galaxy NGC 6822 has a metallicity similar to systems at the epoch of peak star formation. Through identification and study of dusty and dust-producing stars, it is therefore a useful laboratory to shed light on the dust life cycle in the early Universe. We present a catalog of sources combining near- and mid-IR photometry from the United Kingdom Infrared Telescope (UKIRT; $J$, $H$, and $K$) and the $Spitzer$ $Space$ $Telescope$ (IRAC 3.6, 4.5, 5.8, and 8.0 $\mu$m and MIPS 24 $\mu$m). This catalog is employed to identify dusty and evolved stars in NGC 6822 utilizing three color-magnitude diagrams (CMDs). With diagnostic CMDs covering a wavelength range spanning the near- and mid-IR, we develop color cuts using kernel density estimate (KDE) techniques to identify dust-producing evolved stars, including red supergiant (RSG) and thermally-pulsing asymptotic giant branch (TP-AGB) star candidates. In total, we report 1,292 RSG candidates, 1,050 oxygen-rich AGB star candidates, and 560 carbon-rich AGB star candidates with high confidence in NGC 6822. Our analysis of the AGB stars suggests a robust population inhabiting the central stellar bar of the galaxy, with a measured global stellar metallicity of [Fe/H] = -1.286 $\pm$ 0.095, consistent with previous studies. In addition, we identify 277 young stellar object (YSO) candidates. The detection of a large number of YSO candidates within a centrally-located, compact cluster reveals the existence of an embedded, high-mass star-formation region that has eluded previous detailed study. Spitzer I appears to be younger and more active than the other prominent star-forming regions in the galaxy.
- [16] arXiv:2002.12481 [pdf, other]
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Title: The UTMOST pulsar timing programme II: Timing noise across the pulsar populationAuthors: Marcus E. Lower, Matthew Bailes, Ryan M. Shannon, Simon Johnston, Chris Flynn, Stefan Osłowski, Vivek Gupta, Wael Farah, Timothy Bateman, Anne J. Green, Richard Hunstead, Andrew Jameson, Fabian Jankowski, Aditya Parthasarathy, Daniel C. Price, Angus Sutherland, David Temby, Vivek Venkatraman KrishnanComments: Accepted by MNRAS. 28 pages, 8 figures, 8 tablesSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)
While pulsars possess exceptional rotational stability, large scale timing studies have revealed at least two distinct types of irregularities in their rotation: red timing noise and glitches. Using modern Bayesian techniques, we investigated the timing noise properties of 300 bright southern-sky radio pulsars that have been observed over 1.0-4.8 years by the upgraded Molonglo Observatory Synthesis Telescope (MOST). We reanalysed the spin and spin-down changes associated with nine previously reported pulsar glitches, report the discovery of three new glitches and four unusual glitch-like events in the rotational evolution of PSR J1825$-$0935. We develop a refined Bayesian framework for determining how red noise strength scales with pulsar spin frequency ($\nu$) and spin-down frequency ($\dot{\nu}$), which we apply to a sample of 280 non-recycled pulsars. With this new method and a simple power-law scaling relation, we show that red noise strength scales across the non-recycled pulsar population as $\nu^{a} |\dot{\nu}|^{b}$, where $a = -0.84^{+0.47}_{-0.49}$ and $b = 0.97^{+0.16}_{-0.19}$. This method can be easily adapted to utilise more complex, astrophysically motivated red noise models. Lastly, we highlight our timing of the double neutron star PSR J0737$-$3039, and the rediscovery of a bright radio pulsar originally found during the first Molonglo pulsar surveys with an incorrectly catalogued position.
- [17] arXiv:2002.12483 [pdf, other]
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Title: Atmospheric Circulation on Black Widow CompanionsComments: 14 pages, 9 figures. Version accepted for publication in ApJSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
We present a model for atmospheric wind circulation in binary millisecond pulsar (MSP) companions, showing how the optical light curve (LC) and radial velocities (RV) are sensitive to the wind flow, causing LC orbital phase shifts and asymmetries, as observed for several `spider' MSP. Velocity widths of spectral lines offer additional opportunities for measuring surface wind speed. As examples, we fit optical data for a black widow pulsar J1959+2048 and a redback pulsar J2215+5135; the wind heating models (WH) are statistically strongly preferred over direct heating (DH) for both objects, although the latter is even better fit with a heated spot. In general, WH effects tend to increase the inferred orbital inclination $i$ and decrease the inferred companion center-of-mass radial velocity amplitude $K_\mathrm{c}$; both effects decrease the inferred neutron star mass. Even with such a decrease, we find large masses for the two neutron stars: $2.18\pm0.09M_\odot$ and $2.28^{+0.10}_{-0.09}M_\odot$, respectively (for the modest surface speeds fit from the bulk heat flow; supersonic photospheric winds can slightly change these values). These are among the highest masses known, and our improved modeling increases confidence that the results are important for understanding the dense matter equation of state.
- [18] arXiv:2002.12512 [pdf, ps, other]
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Title: Distortion of Magnetic Fields in BHR 71Authors: Ryo Kandori, Motohide Tamura, Masao Saito, Kohji Tomisaka, Tomoaki Matsumoto, Ryo Tazaki, Tetsuya Nagata, Nobuhiko Kusakabe, Yasushi Nakajima, Jungmi Kwon, Takahiro Nagayama, Ken'ichi TatematsuComments: Accepted for publication in ApJSubjects: Astrophysics of Galaxies (astro-ph.GA)
The magnetic field structure of a star-forming Bok globule BHR 71 was determined based on near-infrared polarimetric observations of background stars. The magnetic field in BHR 71 was mapped from 25 stars. By using a simple 2D parabolic function, the plane-of-sky magnetic axis of the core was found to be $\theta_{\rm mag} = 125^{\circ} \pm 11^{\circ}$. The plane-of-sky mean magnetic field strength of BHR 71 was found to be $B_{\rm pos} = 8.8 - 15.0$ $\mu$G, indicating that the BHR 71 core is magnetically supercritical with $\lambda = 1.44 - 2.43$. Taking into account the effect of thermal/turbulent pressure and the plane-of-sky magnetic field component, the critical mass of BHR 71 was $M_{\rm cr} = 14.5-18.7$ M$_{\odot}$, which is consistent with the observed core mass of $M_{\rm core} \approx 14.7$ M$_{\odot}$ (Yang et al. 2017). We conclude that BHR 71 is in a condition close to a kinematically critical state, and the magnetic field direction lies close to the plane of sky. Since BHR 71 is a star-forming core, a significantly subcritical condition (i.e., the magnetic field direction deviating from the plane of sky) is unlikely, and collapsed from a condition close to a kinematically critical state. There are two possible scenarios to explain the curved magnetic fields of BHR 71, one is an hourglass-like field structure due to mass accumulation and the other is the Inoue \& Fukui (2013) mechanism, which proposes the interaction of the core with a shock wave to create curved magnetic fields wrapping around the core.
- [19] arXiv:2002.12513 [pdf, other]
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Title: Proper Motions of the Radio Source Orion MR, Formerly Known as Orion n, and New Sources with Large Proper Motions in Orion BN/KLAuthors: Luis F. Rodriguez, Sergio A. Dzib, Luis Zapata, Susana Lizano, Laurent Loinard, Karl M. Menten, Laura GomezComments: 14 pages, 7 figures, to appear in The Astrophysical JournalSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)
The infrared source known as Orion n was detected in 1980 with observations made with the 3.8-m United Kingdom Infrared Telescope. About two decades later, sensitive observations made with the Very Large Array revealed the presence of a mJy double radio source apparently coincident in position with the infrared source n. The radio source was assumed to be the counterpart of the infrared source. However, over the years it has been concluded that the radio source shows large proper motions to the south while the infrared source n is stationary. Here we reanalyze the proper motions of the radio source adding both older and newer VLA observations than previously used. We confirm the proper motions of the radio source that at present no longer coincides positionally with the infrared source. The solution to this problem is, most probably, that the infrared source n and the radio source are not the same object: the infrared source is a stationary object in the region while the radio counterpart is moving as a result of the explosion that took place in this region some 500 years ago and that expelled large amounts of molecular gas as well as several compact sources. Considering the paper where it was first reported, we refer to this double radio source as Orion MR.
In addition, we use these new observations to fully confirm the large proper motions of the sources IRc23 and Zapata 11. Together with sources BN, I, Orion MR, and x, there are at least six compact sources that recede from a point in common in Orion BN/KL. However, IRc23 is peculiar in that its ejection age appears to be only $\sim$300 years. The relatively large number of sources rules out as a possible mechanism the classic three-body scenario since then only two escaping bodies are expected: a tight binary plus the third star involved in the encounter. - [20] arXiv:2002.12517 [pdf, ps, other]
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Title: Time-Resolved and Energy-Resolved Polarizations of GRB Prompt EmissionComments: 20 pages, 6 figures, Accepted by ApJSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
Besides light curves and spectra, polarization provides a different powerful tool of studying the $\gamma-$ray burst (GRB) prompt phase. Compared with the time-integrated and energy-integrated polarization, time-resolved and energy-resolved polarization can deliver more physical information about the emitting region. Here we investigate time-resolved and energy-resolved polarization of GRB prompt emission using the synchrotron models. We find that the equal arrival time surface effect is very important in shaping the PD curves when the physical conditions of emitting region changes violently with radius. Polarization properties are neither correlated with the spectral lag nor the peak energy evolution patterns. Polarization properties with a mixed magnetic field are very similar to those for a corresponding ordered magnetic field but the former has a smaller polarization degree. The emission at the MeV peak can be highly polarized for a synchrotron model while it is unpolarized as predicted by a dissipative photosphere model. Future energy-resolved polarization observations can distinguish between these two models.
- [21] arXiv:2002.12525 [pdf, other]
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Title: An ALMA Survey of H$_2$CO in Protoplanetary DisksAuthors: Jamila Pegues, Karin I. Öberg, Jennifer B. Bergner, Ryan A. Loomis, Chunhua Qi, Romane Le Gal, L. Ilsedore Cleeves, Viviana V. Guzmán, Jane Huang, Jes K. Jørgensen, Sean M. Andrews, Geoffrey A. Blake, John M. Carpenter, Kamber R. Schwarz, Jonathan P. Williams, David J. WilnerComments: 20 pages, 14 figures, 3 figure sets, 9 tables. Published in ApJ (February 2020)Journal-ref: The Astrophysical Journal, 890, 142 (2020)Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Earth and Planetary Astrophysics (astro-ph.EP); Astrophysics of Galaxies (astro-ph.GA)
H$_2$CO is one of the most abundant organic molecules in protoplanetary disks and can serve as a precursor to more complex organic chemistry. We present an ALMA survey of H$_2$CO towards 15 disks covering a range of stellar spectral types, stellar ages, and dust continuum morphologies. H$_2$CO is detected towards 13 disks and tentatively detected towards a 14th. We find both centrally-peaked and centrally-depressed emission morphologies, and half of the disks show ring-like structures at or beyond expected CO snowline locations. Together these morphologies suggest that H$_2$CO in disks is commonly produced through both gas-phase and CO-ice-regulated grain-surface chemistry. We extract disk-averaged and azimuthally-averaged H$_2$CO excitation temperatures and column densities for four disks with multiple H$_2$CO line detections. The temperatures are between 20-50K, with the exception of colder temperatures in the DM Tau disk. These temperatures suggest that H$_2$CO emission in disks is generally emerging from the warm molecular layer, with some contributions from the colder midplane. Applying the same H$_2$CO excitation temperatures to all disks in the survey, we find that H$_2$CO column densities span almost three orders of magnitude ($\sim 5 \times 10^{11} - 5 \times 10^{14} \mathrm{cm}^{-2}$). The column densities appear uncorrelated with disk size and stellar age, but Herbig Ae disks may have less H$_2$CO compared to T Tauri disks, possibly because of less CO freeze-out. More H$_2$CO observations towards Herbig Ae disks are needed to confirm this tentative trend, and to better constrain under which disk conditions H$_2$CO and other oxygen-bearing organics efficiently form during planet formation.
- [22] arXiv:2002.12533 [pdf, other]
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Title: First Constraints on Compact Dark Matter from Fast Radio Burst MicrostructureAuthors: Mawson W. Sammons, Jean-Pierre Macquart, Ron D. Ekers, Ryan M. Shannon, Hyerin Cho, J. Xavier Prochaska, Adam T. Deller, Cherie K. DayComments: 9 pages, 5 Figures, 1 table, Submitted to ApJ LettersSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Astrophysical Phenomena (astro-ph.HE)
Despite existing constraints it remains possible that up to $35\%$ of all dark matter is comprised of compact objects, such as the black holes in the 10-100\,M$_\odot$ range whose existence has been confirmed by LIGO. The strong gravitational lensing of transients such as FRBs and GRBs has been suggested as a more sensitive probe for compact dark matter than intensity fluctuations observed in microlensing experiments. Recently ASKAP has reported burst substructure down to $15\mu$s timescales in FRBs in the redshift range $0.3-0.5$. We investigate here the implications of this for the detectability of dark matter by FRBs. A sample size of $\sim 10^3$ localized FRBs is required to exclude the fraction of dark matter in compact objects in the 10-100M$_\odot$ range, residing in intercepted individual galaxy halos (with impact distances $\lesssim 50\,$kpc) along FRB sightlines, to less than 35$\%$ with 95$\%$ confidence. Approximately $10^2$ localised FRBs would be required to constrain dark matter to a similar level if it were distributed along $\gtrsim 1\,$Gpc-long FRB sightlines through the cosmic web. Conversely, existing constraints on the fraction of compact dark matter permit as many as 1 in $\approx 50$ of all $z \lesssim 0.4$ FRBs to exhibit micro-lensed burst structure. We further consider the constraints that recently observed high time resolution FRB pulse profiles place on dark matter substructure on yet smaller scales, through the cumulative effect of a large collection of tiny lenses on the pulse profile; we conclude that, even if present, their effect is likely not yet observed.
- [23] arXiv:2002.12539 [pdf, other]
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Title: Spectropolarimetric analysis of FRB 181112 at microsecond resolution: Implications for Fast Radio Burst emission mechanismAuthors: Hyerin Cho, Jean-Pierre Macquart, Ryan M. Shannon, Adam T. Deller, Ian S. Morrison, Ron D. Ekers, Keith W. Bannister, Wael Farah, Hao Qiu, Mawson W. Sammons, Matthew Bailes, Shivani Bhandari, Cherie K. Day, Clancy W. James, Chris J. Phillips, J. Xavier Prochaska, John TuthillComments: Accepted to ApJ Letters; 13 pages, 5 figuresSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
We have developed a new coherent dedispersion mode to study the emission of Fast Radio Bursts that trigger the voltage capture capability of the Australian SKA Pathfinder (ASKAP) interferometer. In principle the mode can probe emission timescales down to 3 ns with full polarimetric information preserved. Enabled by the new capability, here we present a spectropolarimetric analysis of FRB 181112 detected by ASKAP, localized to a galaxy at redshift 0.47. At microsecond time resolution the burst is resolved into four narrow pulses with a rise time of just $15 \mu$s for the brightest. The pulses have a diversity of morphology, but do not show evidence for temporal broadening by turbulent plasma along the line of sight, nor is there any evidence for periodicity in their arrival times. The pulses are highly polarized (up to 95%), with the polarization position angle varying both between and within pulses. The pulses have apparent rotation measures that vary by $15\pm 2\, {\rm rad \,m^{-2}}$ and apparent dispersion measures that vary by $0.041\pm 0.004\,{\rm pc\,cm^{-3}}$. Conversion between linear and circular polarization is observed across the brightest pulse. We conclude that the FRB 181112 pulses are most consistent with being a direct manifestation of the emission process or the result of propagation through a relativistic plasma close to the source. This demonstrates that our method, which facilitates high-time-resolution polarimetric observations of FRBs, can be used to study not only burst emission processes, but also a diversity of propagation effects present on the gigaparsec paths they traverse.
- [24] arXiv:2002.12574 [pdf, other]
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Title: A multi-wavelength view of the open cluster NGC 2527: Discovery of active starsSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)
Star clusters are ideal platforms for categorising X-ray emitting stars and to study X-ray emission as a function of stellar age and activity. We present a comprehensive study of an open star cluster, NGC2527, by combining data from XMM-UVOT-Gaia. Cluster membership of stars and their photometry are taken from Gaia and cross-matched with XMM and UVOT detections. We estimate the age of NGC2527 as ~630 Myr, reddening as E(B-V)=0.13 mag, and a distance of 642+/-30 pc using PARSEC isochrones. We detect 5 sub-subgiants and 5 bandgap stars, which defy single star evolution. We estimate the temperature, mass, radius, and luminosity of 53 single stars and 10 potential binary stars using a python code which fits single and composite Kurucz spectra to broad-band Spectral Energy Distribution. Among the 12 X-ray emitting members, we find 5 are potential RS CVn type binaries, 2 are potential FK Comae type of RGB stars, and 5 are main sequence (MS) stars with high coronal activity. Members with strong UV emission comprise of 1 RGB star, and several MS stars with UV excess suggestive of chromospheric activity. Based on comparison with other clusters, we tentatively suggest that X-ray luminosity of both RS CVn and contact binaries increases with age suggesting more active binaries are present in older clusters as compared to younger clusters. This study suggests the possible presence of W UMa and FK Comae type stars in younger (age~630 Myr) clusters.
- [25] arXiv:2002.12577 [pdf, other]
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Title: Does $Λ$CDM really be in tension with the Hubble diagram data?Comments: 8 pages, 5 figures, comments are welcomeSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
In this article, we elaborate further on the $\Lambda$CDM "tension", suggested recently by the authors \cite{Lusso:2019akb,Risaliti:2018reu}. We combine Supernovae type Ia (SNIa) with quasars (QSO) and Gamma Ray Bursts (GRB) data in order to reconstruct a model independent Hubble diagram to as high redshifts as possible. Specifically, in the case of either SNIa or SNIa/QSO data, we find that the cosmokinetic parameters extracted from the Gaussian process are consistent with those of $\Lambda$CDM. Including GRBs, in the analysis, we find a tension, which however is not as significant as that mentioned in \cite{Lusso:2019akb, Risaliti:2018reu}. Finally, we argue that the choice of the kernel function used in extracting the luminosity distance might affect the amount of tension.
- [26] arXiv:2002.12583 [pdf, ps, other]
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Title: On the formation of PSR J1640+2224: a neutron star born massive?Comments: 24 pages, 5 figures, accepted for publication in ApJSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)
PSR J1640+2224 is a binary millisecond pulsar (BMSP) with a white dwarf (WD) companion. Recent observations indicate that the WD is very likely to be a $\sim 0.7\,M_{\odot}$ CO WD. Thus the BMSP should have evolved from an intermediate-mass X-ray binary (IMXB). However, previous investigations on IMXB evolution predict that the orbital periods of the resultant BMSPs are generally $<40$ days, in contrast with the 175 day orbital period of PSR J1640+2224. In this paper, we explore the influence of the mass of the neutron star (NS) and the chemical compositions of the companion star on the formation of BMSPs. Our results show that, the final orbital period becomes longer with increasing NS mass, and the WD mass becomes larger with decreasing metallicity. In particular, to reproduce the properties of PSR J1640+2224, the NS was likely born massive ($>2.0\,M_{\odot}$).
- [27] arXiv:2002.12598 [pdf, other]
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Title: PPN motion of the S-stars around Sgr A*Authors: R. I. GainutdinovComments: Prepared for submission to 'Astrophysics' journalSubjects: Astrophysics of Galaxies (astro-ph.GA); General Relativity and Quantum Cosmology (gr-qc)
Parametrized Post-Newtonian (PPN) equations of motion for several S-stars nearest to the Galactic Center compact relativistic object SgrA* are considered. The effect of the orbital periods difference between Newtonian and Post-Newtonian cases is taken into account. The best fit PN orbit of S2 has a period which is 16 days longer than Newtonian one. The PPN parameters $\beta_\text{PPN}$ and $\gamma_\text{PPN}$ are measured. Bayesian sampling is used to fit the trajectories of the PPN laws of motion. Posterior estimates of $\beta_\text{PPN}$ and $\gamma_\text{PPN}$ are $0.97^{+0.42}_{-0.65}$ and $0.81^{+0.46}_{-0.60}$ respectively. The result confirms General Relativity prediction for the Post-Newtonian equations of motion in the conditions of orbital motions in vicinity of the SgrA*.
- [28] arXiv:2002.12600 [pdf, other]
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Title: 2MASS J15460752-6258042: a mid-M dwarf hosting a prolonged accretion discComments: 7 pages, 6 figuresSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Earth and Planetary Astrophysics (astro-ph.EP); Astrophysics of Galaxies (astro-ph.GA)
We report the discovery of the oldest (~55 Myr) mid-M type star known to host on-going accretion. 2MASS J15460752-6258042 (2M1546, spectral type M5, 59.2 pc) shows spectroscopic signs of accretion such as strong Ha, He I, and [O I] emission lines, from which we estimate an accretion rate of ~10^-10 Msun/yr. Considering the clearly detected infrared excess in all WISE bands, the shape of its spectral energy distribution and its age, we believe the star is surrounded by a transitional disc, clearly with some gas still present at inner radii. The position and kinematics of the star from Gaia DR2 and our own radial velocity measurements suggest membership in the nearby ~55 Myr-old Argus moving group. At only 59pc from Earth, 2M1546 is one of the nearest accreting mid-M dwarfs, making it an ideal target for studying the upper limit on the lifetimes of gas-rich discs around low mass stars.
- [29] arXiv:2002.12650 [pdf]
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Title: Indexing Exoplanets with Physical Conditions Potentially Suitable for Rock-Dependent ExtremophilesAuthors: Madhu Kashyap Jagadeesh, Sagarika Rao Valluri, Vani Kari, Katarzyna Kubska, Łukasz KaczmarekJournal-ref: LIFE, 2020Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
The search for different life forms elsewhere in the universe is a fascinating area of research in astrophysics and astrobiology. Currently, according to the NASA Exoplanet Archive database, 3876 exoplanets have been discovered. The Earth Similarity Index (ESI) is defined as the geometric mean of radius, density, escape velocity, and surface temperature and ranges from 0 (dissimilar to Earth) to 1 (similar to Earth). The ESI was created to index exoplanets on the basis of their similarity to Earth. In this paper, we examined rocky exoplanets whose physical conditions are potentially suitable for the survival of rock-dependent extremophiles, such as the cyanobacteria Chroococcidiopsis and the lichen Acarospora. The Rock Similarity Index (RSI) is first introduced and then applied to 1659 rocky exoplanets. The RSI represents a measure for Earth-like planets on which physical conditions are potentially suitable for rocky extremophiles that can survive in Earth-like extreme habitats (i.e., hot deserts and cold, frozen lands).
- [30] arXiv:2002.12656 [pdf, ps, other]
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Title: Let there be more variability in two gamma Cas starsAuthors: Yael Naze (ULiege), Andrzej Pigulski (Univ. Wroclaw), Gregor Rauw (ULiege), Myron Smith (NOAO)Comments: accepted by MNRAS - the arxiv version has some figures in low-resolutionSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
We investigate the short-term optical variability of two gamma Cas analogs, pi Aqr and BZ Cru, thanks to intensive ground-based spectroscopic and space-borne photometric monitorings. For both stars, low-amplitude (mmag) coherent photometric variability is detected. The associated signals display long-term amplitude variations, as in other Be stars. However, these signals appear at high frequencies, especially in pi Aqr, indicating p-modes with a high degree l, a quite unusual feature amongst Be stars. While BZ Cru presents only low-level spectral variability, without clear periodicity, this is not the case of pi Aqr. In this star, the dominant photometric frequencies, near ~12/d, are confirmed spectroscopically in separate monitorings taken during very different disk activity levels ; the spectroscopic analysis suggests a probable tesseral nature for the mode.
- [31] arXiv:2002.12658 [pdf, other]
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Title: Filtering techniques to enhance optical turbulence forecast performances at short time scalesAuthors: E. Masciadri, G. Martelloni, A. Turchi (INAF - Osservatorio Astrofisico di Arcetri, Florence, Italy)Comments: 7 figures, 10 tablesJournal-ref: Masciadri et al., 2020, MNRAS, 2020, 492, 140Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Atmospheric and Oceanic Physics (physics.ao-ph)
The efficiency of the management of top-class ground-based astronomical facilities supported by Adaptive Optics (AO) relies on our ability to forecast the optical turbulence (OT) and a set of relevant atmospheric parameters. Indeed, in spite of the fact that the AO is able to achieve, at present, excellent levels of wavefront corrections (a Strehl Ratio up to 90% in H band), its performances strongly depend on the atmospheric conditions. Knowing in advance the turbulence conditions allows an optimization of the AO use. It has already been proven that it is possible to provide reliable forecasts of the optical turbulence (CN2 profiles and integrated astroclimatic parameters such as seeing, isoplanantic angle, wavefront coherence time, ...) for the next night. In this paper we prove that it is possible to improve the forecast performances on shorter time scales (order of one or two hours) with consistent gains (order of 2 to 8) using filtering techniques. This has permitted us to achieve forecasts accuracies never obtained before and reach a fundamental milestone for the astronomical applications. The time scale of one or two hours is the most critical one for an efficient management of the ground-based telescopes supported by AO. Results shown here open, therefore, to an important revolution in the field. We implemented this method in the operational forecast system of the Large Binocular Telescope, named ALTA Center that is, at our knowledge, the first operational system providing forecasts of turbulence and atmospheric parameters at short time scales to support science operations.
- [32] arXiv:2002.12673 [pdf, ps, other]
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Title: The Spatial Evolution of Young Massive Clusters II. Looking for Imprints of Star Formation in NGC 2264 with Gaia DR2Authors: Anne S.M. Buckner, Zeinab Khorrami, Marta Gonzalez, Stuart L. Lumsden, Estelle Moraux, Rene D. Oudmaijer, Paul Clark, Isabelle Joncour, Jose Manuel Blanco, Ignacio de la Calle, Alvaro Hacar, Jose M. Herrera-Fernandez, Frederique Motte, Jesus Salgado, Luis Valero-MartinComments: 13 pages, 4 figures, 5 tables, Accepted for publication in A&ASubjects: Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)
Aims. To demonstrate that INDICATE is a powerful spatial analysis tool which when combined with kinematic data from Gaia DR2 can be used to robustly probe a cluster's star formation history.
Methods. We compare the dynamic and spatial distributions of Young Stellar Objects (YSOs) at different evolutionary stages in NGC 2264 using Gaia DR2 proper motion data and INDICATE.
Results. Both the dynamic and spatial behaviour of YSOs at different evolutionary stages are distinct. Dynamically, Class IIs predominately have non-random trajectories which are consistent with known substructures, whereas Class IIIs have random trajectories with no clear expansion or contraction patterns. Spatially, there is a correlation between evolutionary stage and source concentration, with 69.4% (Class 0/I), 27.9% (Class II) and 7.7% (Class III) found to be clustered. The proportion of YSOs clustered with objects of the same class follows this trend also. Class 0/Is are found to be both more tightly clustered with the general populous/ objects of the same class than Class IIs and IIIs by a factor of 1.2/ 4.1 and 1.9/ 6.6 respectively. An exception to these findings is within 0.05 degrees of S Mon where Class IIIs mimic the behaviours of Class IIs across the wider cluster region. Our results suggest (i) current YSOs distributions are a result of dynamical evolution, (ii) prolonged star formation has been occurring sequentially, (iii) stellar feedback from S Mon is causing YSOs to appear as more evolved sources.
Conclusions. INDICATE is a powerful tool with which to perform rigorous spatial analyses as it - crucially - provides a quantitative measure of clustering behaviours. Our findings are consistent with what is known about NGC 2264, effectively demonstrating that when combined with kinematic data from Gaia DR2 INDICATE can be used to robustly study the star formation history of a cluster. - [33] arXiv:2002.12689 [pdf, other]
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Title: A major optical & X-ray outburst from the Magellanic Bridge source RX J0209.6-7427Authors: Malcolm J. Coe, Itumeleng M. Monageng, Elizabeth S. Bartlett, David A. H. Buckley, Andrzej UdalskiComments: 6 pages, 6 figures. Submitted for publication in MNRASSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
RX J0209.6-7427 is an X-ray source in the Magellanic Bridge that was first detected in 1993, but not seen again till 2019. It has been identified as a member of the Be/X-ray binary class, a category of objects that are well established as bright, often-unpredictable transients. Such systems are rarely known in the Bridge, possibly because they lie outside the area most commonly studied by X-ray telescopes. Whatever the reason for the sparse number of such systems in the Bridge, they can provide useful tools for trying to understand the result of the tidal dynamics of the two Magellanic Clouds. In this paper the nature of the object is explored with the help of new data obtained during the latest outburst. In particular, the first optical spectrum of the counterpart is presented to help classify the star, plus measurements of the Balmer emission lines over several years are used to investigate changes in the size and structure of the circumstellar disk.
- [34] arXiv:2002.12692 [pdf, other]
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Title: [CII] 158 μm self-absorption and optical depth effectsAuthors: C. Guevara, J. Stutzki, V. Ossenkopf-Okada, R. Simon, J. P. Pérez-Beaupuits, H. Beuther, S. Bihr, R. Higgins, U. Graf, R. GüstenComments: 40 pages, 49 figuresSubjects: Astrophysics of Galaxies (astro-ph.GA)
Context. The [CII] 158 {\mu}m far-infrared (FIR) fine-structure line is one of the most important cooling lines of the star-forming interstellar medium (ISM). High spectral resolution observations have shown complex structures in the line profiles of the [CII] emission. Aims. Our aim is to determine whether the complex profiles observed in [^{12}CII] are due to individual velocity components along the line-of-sight or to self-absorption based on a comparison of the [^{12}CII] and isotopic [^{13}CII] line profiles. Methods. Deep integrations with the SOFIA/upGREAT 7-pixel array receiver in M43, Horsehead~PDR, Monoceros~R2, and M17~SW allow for the detection of optically thin [^{13}CII] emission lines, along with the [^{12}CII] emission lines, with a high signal-to-noise ratio. We first derived the [^{12}CII] optical depth and the [CII] column density from a single component model. However, the complex line profiles observed require a double layer model with an emitting background and an absorbing foreground. A multi-component velocity fit allows us to derive the physical conditions of the [CII] gas: column density and excitation temperature. Results. We find moderate to high [^{12}CII] optical depths in all four sources and self-absorption of [^{12}CII] in Mon R2 and M17 SW. The high column density of the warm background emission corresponds to an equivalent Av of up to 41 mag. The foreground absorption requires substantial column densities of cold and dense [CII] gas, with an equivalent Av ranging up to about 13 mag. Conclusions. The column density of the warm background material requires multiple photon-dominated region (PDR) surfaces stacked along the line of sight and in velocity. The substantial column density of dense and cold foreground [CII] gas detected in absorption cannot be explained with any known scenario and we can only speculate on its origins
- [35] arXiv:2002.12695 [pdf, other]
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Title: Optimising tomography for weak gravitational lensing surveysAuthors: Marvin Sipp (1), Bjoern Malte Schaefer (1), Robert Reischke (2, 3) ((1) ZAH Heidelberg, (2) Technion Haifa, (3) Open University of Israel)Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
The subject of this paper is optimisation of weak lensing tomography: We carry out numerical minimisation of a measure of total statistical error as a function of the redshifts of the tomographic bin edges by means of a Nelder-Mead-algorithm to optimise the sensitivity of weak lensing with respect to different optimisation targets. Working under the assumption of a Gaussian likelihood for the parameters of a $w$CDM-model and using Euclid's survey specifications, we show that optimisations are feasible and provide reductions of the statistical errors by up to a few 10%. Commonly, optimising tomography places bins at higher redshift than conventional binning. More importantly, we find that nearly saturated information content can be gained using few tomographic bins. This is crucial for photometric redshift surveys with large redshift errors. We consider a large range of targets for optimisation that can be computed from the parameter covariance (or equivalently, from the Fisher-matrix), and extend these studies to information entropy measures such as the Kullback-Leibler-divergence.
- [36] arXiv:2002.12700 [pdf, other]
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Title: Machine Learning meets the redshift evolution of the CMB TemperatureAuthors: Rubén ArjonaComments: 17 pages, 5 figures and 1 table. Comments welcomeSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Phenomenology (hep-ph)
We present a model independent and non-parametric reconstruction with a Machine Learning algorithm of the redshift evolution of the Cosmic Microwave Background (CMB) temperature from a wide redshift range $z\in \left[0,3\right]$ without assuming any dark energy model, an adiabatic universe or photon number conservation. In particular we use the genetic algorithms which avoid the dependency on an initial prior or a cosmological fiducial model. Through our reconstruction we constrain new physics at late times. We provide novel and updated estimates on the $\beta$ parameter from the parametrisation $\text{T}(z)=\text{T}_0(1+z)^{1-\beta}$, the duality relation $\eta(z)$ and the cosmic opacity parameter $\tau(z)$. Furthermore we place constraints on a spatial varying fine structure constant $\alpha$, which would have signatures in a broad spectrum of physical phenomena such as the CMB anisotropies. Overall we find no evidence of deviations within the $1\sigma$ region from the well established $\Lambda\text{CDM}$ model, thus confirming its predictive potential.
- [37] arXiv:2002.12708 [pdf]
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Title: Characteristics of SEPs during Solar Cycle 21-24Comments: 17 pages, 6 figures (accepted for the publication in Journal of Astrophysics and Astronomy)Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Space Physics (physics.space-ph)
The study of the solar energetic particle events (SEPs) and their association with solar flares and other activities are very crucial to understand the space weather. Keeping this in view, in this paper, we present the study of the SEPs (intensity equal to or greater than 10 pfu) during the solar cycle 21 to 24 (1976-2017) in > 10 MeV energy channels associated with solar flares. For our analysis, we have used the data from different instruments onboard SOHO satellite. We have examined the flare size, source location, CMEs characteristics of associated SEPs. About 31% and 69% of the SEPs were originated from the eastern and western solar hemisphere respectively. The average CME speed and width were 1238 km/s and 253 deg respectively. About 58 % SEPs were associated with halo CMEs and 42% of SEPs associated with CMEs width varying from 10 deg to 250 deg respectively.
- [38] arXiv:2002.12712 [pdf, ps, other]
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Title: TNOs are Cool! A Survey of the transneptunian Region XV. Physical characteristics of 23 resonant transneptunian and scattered disk objectsAuthors: A. Farkas-Takács, Cs. Kiss, E. Vilenius, G. Marton, T.G. Müller, M. Mommert, J. Stansberry, E. Lellouch, P. Lacerda, A. PálComments: Accepted for publication in A&ASubjects: Earth and Planetary Astrophysics (astro-ph.EP)
The goal of this work is to determine the physical characteristics of resonant, detached and scattered disk objects in the transneptunian region, observed mainly in the framework of the "TNOs are Cool!" Herschel Open Time Key Program. Based on thermal emission measurements with the Herschel/PACS and Spitzer/MIPS instruments we determine size, albedo, and surface thermal properties for 23 objects using radiometric modelling techniques. This is the first analysis in which the physical properties of objects in the outer resonances are determined for a notable sample. In addition to the results for individual objects, we have compared these characteristics with the bulk properties of other populations of the transneptunian region. The newly analyzed objects show a large variety of beaming factors, indicating a diversity of thermal properties, and in general, they follow the albedo-colour clustering identified earlier for Kuiper belt objects and Centaurs, further strengthening the evidence for a compositional discontinuity in the young Solar System.
- [39] arXiv:2002.12714 [pdf, other]
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Title: CMB-HD: Astro2020 RFI ResponseAuthors: Neelima Sehgal, Simone Aiola, Yashar Akrami, Kaustuv moni Basu, Michael Boylan-Kolchin, Sean Bryan, Caitlin M Casey, Sébastien Clesse, Francis-Yan Cyr-Racine, Luca Di Mascolo, Simon Dicker, Thomas Essinger-Hileman, Simone Ferraro, George Fuller, Nicholas Galitzki, Dongwon Han, Matthew Hasselfield, Gil Holder, Bhuvnesh Jain, Bradley R. Johnson, Matthew Johnson, Pamela Klaassen, Amanda MacInnis, Mathew Madhavacheril, Philip Mauskopf, Daan Meerburg, Joel Meyers, Tony Mroczkowski, Suvodip Mukherjee, Moritz Münchmeyer, Sigurd Kirkevold Naess, Daisuke Nagai, Toshiya Namikawa, Laura Newburgh, Nam Nguyen, Michael Niemack, Benjamin D. Oppenheimer, Elena Pierpaoli, Emmanuel Schaan, Blake Sherwin, Anže Slosar, David Spergel, Eric Switzer, Pranjal Trivedi, Yu-Dai Tsai, Alexander van Engelen, et al. (2 additional authors not shown)Comments: Response to request for information (RFI) by the Panel of Radio, Millimeter, and Submillimeter Observations from the Ground (RMS) of the Astro2020 Decadal Survey regarding the CMB-HD APC (arXiv:1906.10134). Note some text overlap with original APC. Note also detector count and cost have been reduced by 1/3, and observing time increased by 1/3 compared to original APC; science goals expandedSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Instrumentation and Methods for Astrophysics (astro-ph.IM); High Energy Physics - Phenomenology (hep-ph)
CMB-HD is a proposed ultra-deep (0.5 uk-arcmin), high-resolution (15 arcseconds) millimeter-wave survey over half the sky that would answer many outstanding questions in both fundamental physics of the Universe and astrophysics. This survey would be delivered in 7.5 years of observing 20,000 square degrees, using two new 30-meter-class off-axis cross-Dragone telescopes to be located at Cerro Toco in the Atacama Desert. Each telescope would field 800,000 detectors (200,000 pixels), for a total of 1.6 million detectors.
- [40] arXiv:2002.12734 [pdf, other]
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Title: Mass transfer of low-mass binaries and chemical anomalies among unevolved stars in globular clustersComments: 11 pages, 9 figures, 1 tableSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
While it is well known that mass transfer in binaries can pollute the surfaces of the accretors, it is still unclear whether this mechanism can reproduce the observed chemical inhomogeneities in globular clusters. We study the surface abundances of the accretors in low-mass binaries, as a first step towards understanding whether mass transfer in low-mass binaries is one of the potential origins of the aforementioned abundance anomalies in globular clusters. We use the Modules for Experiments in Stellar Astrophysics code to calculate binary evolutionary models with different initial donor masses between 0.9 and 1.9 $ \rm {M}_\odot$ for an initial metallicity of Z = 0.0034. The results show that in some low-mass binary systems, the accretors exhibit peculiar chemical patterns when they are still unevolved stars, e.g. C and O depletion; Na and N enhancement; constant Mg, Al and C+N+O. The abundance patterns of the accretors are significantly different from their initial abundances (or that of normal single stars), and can match the observed populations. These abundance patterns strongly depend not only on the initial parameters of binaries (donor mass, mass ratio, and orbital period), but also on the assumptions regarding mass-transfer efficiency and angular momentum loss. These results support the hypothesis that mass transfer in low-mass binaries is at least partly responsible for the unevolved anomalous stars in globular clusters. More work on binary evolutionary models and binary population synthesis is required to fully evaluate the contribution of this scenario.
- [41] arXiv:2002.12736 [pdf, other]
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Title: Near optimal angular quadratures for polarised radiative transferComments: 7 pages, 3 figures, 2 tables; accepted for publication in A&ASubjects: Solar and Stellar Astrophysics (astro-ph.SR); Earth and Planetary Astrophysics (astro-ph.EP); Astrophysics of Galaxies (astro-ph.GA)
In three-dimensional (3D) radiative transfer (RT) problems, the tensor product quadratures are generally not optimal in terms of the number of discrete ray directions needed for a given accuracy of the angular integration of the radiation field. In this paper, we derive a new set of angular quadrature rules more suitable for solving 3D RT problems with the short- and long-characteristics formal solvers. These quadratures are more suitable than the currently used ones for numerical calculation of the radiation field tensors that are relevant in non-LTE radiative transfer problems with polarisation. We show that our new quadratures can save up to about 30 % of computing time with respect to the Gaussian-trapezoidal product quadratures with the same accuracy.
- [42] arXiv:2002.12739 [pdf]
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Title: The Case for Probe-class NASA Astrophysics MissionsAuthors: Martin Elvis (1), Jon Arenberg (2), David Ballantyne (3), Mark Bautz (4), Charles Beichman (5), Jeffrey Booth (5), James Buckley (6), Jack O. Burns (7), Jordan Camp (8), Alberto Conti (9), Asantha Cooray (10), William Danchi (8), Jacques Delabrouille (11), Gianfranco De Zotti (12), Raphael Flauger (13), Jason Glenn (7), Jonathan Grindlay (1), Shaul Hanany (14), Dieter Hartmann (15), George Helou (16), Diego Herranz (17), Johannes Hubmayr (18), Bradley R. Johnson (19), William Jones (20), N. Jeremy Kasdin (20), Chryssa Kouvoliotou (21), Kerstin E. Kunze (22), Charles Lawrence (5), Joseph Lazio (5), Sarah Lipscy (9), Charles F. Lillie (23), Tom Maccarone (24), Kristin C. Madsen (25), Richard Mushotzky (26), Angela Olinto (27), Peter Plavchan (28), Levon Pogosian (29), Andrew Ptak (8), Paul Ray (30), et al. (9 additional authors not shown)Comments: Submitted to the Astro2020 Decadal Survey call for Activities, Projects or State of the Profession Consideration (APC). 10 pagesSubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Astrophysics of Galaxies (astro-ph.GA)
Astrophysics spans an enormous range of questions on scales from individual planets to the entire cosmos. To address the richness of 21st century astrophysics requires a corresponding richness of telescopes spanning all bands and all messengers. Much scientific benefit comes from having the multi-wavelength capability available at the same time. Most of these bands,or measurement sensitivities, require space-based missions. Historically, NASA has addressed this need for breadth with a small number of flagship-class missions and a larger number of Explorer missions. While the Explorer program continues to flourish, there is a large gap between Explorers and strategic missions. A fortunate combination of new astrophysics technologies with new, high capacity, low dollar-per-kg to orbit launchers, and new satellite buses allow for cheaper missions with capabilities approaching strategic mission levels. NASA has recognized these developments by calling for Probe-class mission ideas for mission studies, spanning most of the electromagnetic spectrum from GeV gamma-rays to the far infrared, and the new messengers of neutrinos and ultra-high energy cosmic rays. The key insight from the Probes exercise is that order-of-magnitude advances in science performance metrics are possible across the board for initial total cost estimates in the range 500M-1B dollars.
- [43] arXiv:2002.12774 [pdf, ps, other]
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Title: Can Orbital Clustering of KBOs in the Ecliptic be due to the Solar Toroidal Field Generated Spacetime Dragging?Authors: Babur M. MirzaJournal-ref: Astrophys Space Sci 365, 31 (2020)Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)
The Kuiper belt objects (KBOs) exhibit an orbital clustering of the outer planets lying at perihelion distances larger than Neptune and semimajor axes greater than 150 AU from the Sun. This implies a hitherto unknown dynamical mechanism to counter randomizing of the orbital elements caused by the giant solar system planets. Using the toroidal field induced frame-dragging we deduce here the observed range of the Kuiper belt region, the semi-major axis of Sedna like objects in the Kuiper belt, as well as the orbital clustering of the KBOs in the ecliptic, without assuming dynamical effects induced by trans-Neptunian-objects (TNOs). We also calculate the orbital precession rates for the inner planets and show their correspondence, within the range of observational accuracy, with recent planetary ephemerides.
- [44] arXiv:2002.12775 [pdf, other]
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Title: NuSTAR observations of G11.2-0.3Journal-ref: ApJ, 2020, 889, 23Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)
We present in this paper the hard X-ray view of the pulsar wind nebula in G11.2-0.3 and its central pulsar PSR J1811-1925 as seen by NuSTAR. We complement the data with Chandra for a more complete picture and confirm the existence of a hard, power-law component in the shell with photon index Gamma = 2.1 +/- 0.1, which we attribute to synchrotron emission. Our imaging observations of the shell show a slightly smaller radius at higher energies, consistent with Chandra results, and we find shrinkage as a function of increased energy along the jet direction, indicating that the electron outflow in the PWN may be simpler than that seen in other young PWNe. Combining NuSTAR with Integral, we find that the pulsar spectrum can be fit by a power-law with Gamma=1.32 +/- 0.07 up to 300 keV without evidence of curvature.
- [45] arXiv:2002.12778 [pdf, other]
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Title: Constraints on Primordial Black HolesComments: 59 pages, 21 figures, REVTeX 4.1. arXiv admin note: text overlap with arXiv:0912.5297Subjects: 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)
We update the constraints on the fraction of the Universe going into primordial black holes (PBHs) over the mass range $10^{-5}$--$10^{50}$ g. Those smaller than $\sim 10^{15}$ g would have evaporated by now due to Hawking radiation, so their abundance at formation is constrained by the effects of evaporated particles on big bang nucleosynthesis, the cosmic microwave background (CMB), the Galactic and extragalactic $\gamma$-ray and cosmic ray backgrounds and the possible generation of stable Planck mass relics. PBHs larger than $\sim 10^{15}$ g are subject to a variety of constraints associated with gravitational lensing, dynamical effects, influence on large-scale structure, accretion and gravitational waves. We discuss the constraints on both the initial collapse fraction and the current fraction of the cold dark matter in PBHs at each mass scale but stress that many of the constraints are associated with observational or theoretical uncertainties and some are no longer applicable. We also consider indirect constraints associated with the amplitude of the primordial density fluctuations, such as second-order tensor perturbations and $\mu$-distortions arising from the effect of acoustic reheating on the CMB, but these only apply if PBHs are created from the high-$\sigma$ peaks of nearly Gaussian fluctuations. Finally we discuss how the constraints are modified if the PBHs have an extended mass function, this being relevant if PBHs provide some combination of the dark matter, the LIGO/Virgo coalescences and the seeds for cosmic structure.
- [46] arXiv:2002.12820 [pdf, other]
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Title: On structure and kinematics of the Virgo cluster of galaxiesComments: 10 pages, 10 figures, 6 tables. Accepted for publication on Astronomy & AstrophysicsSubjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
Aims. This work considers the Virgo cluster of galaxies, focusing on its structure, kinematics, and morphological landscape. Our principal aim is to estimate the virial mass of the cluster. For this purpose, we present a sample of 1537 galaxies with radial velocities $V_{LG} < 2600$~km~s$^{-1}$ situated within a region of $\Delta{}SGL = 30^\circ$ and $\Delta{}SGB = 20^\circ$ around M87. About half of the galaxies have distance estimates.
Methods. We selected 398 galaxies with distances in a $(17\pm5)$~Mpc range. Based on their 1D and 2D number-density profiles and their radial velocity dispersions, we made an estimate for the virial mass of the Virgo cluster.
Results. We identify the infall of galaxies towards the Virgo cluster core along the Virgo Southern Extension filament. From a 1D profile of the cluster, we obtain the virial mass estimate of $(6.3\pm0.9) \times 10^{14} M_\odot, $ which is in tight agreement with its mass estimate via the external infall pattern of galaxies.
Conclusions. We conclude that the Virgo cluster outskirts between the virial radius and the zero-velocity radius do not contain significant amounts of dark matter beyond the virial radius. - [47] arXiv:2002.12823 [pdf, other]
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Title: Modeling the Infrared Reverberation Response of the Circumnuclear Dusty Torus in AGNs: An Investigation of Torus Response FunctionsComments: 38 pages, 36 figures (13 in appendices), published in the Astrophysical JournalSubjects: Astrophysics of Galaxies (astro-ph.GA)
The size and structure of the dusty circumnuclear torus in active galactic nuclei (AGN) can be investigated by analyzing the temporal response of the torus's infrared (IR) dust emission to variations in the AGN ultraviolet/optical luminosity. This method, reverberation mapping, is applicable over a wide redshift range, but the IR response is sensitive to several poorly constrained variables relating to the dust distribution and its illumination, complicating the interpretation of measured reverberation lags. We have used an enhanced version of our torus reverberation mapping code (TORMAC) to conduct a comprehensive exploration of the torus response functions at selected wavelengths, for the standard interstellar medium grain composition. The shapes of the response functions vary widely over the parameter range covered by our models, with the largest variations occurring at shorter wavelengths ($\leq 4.5\,\mu$m). The reverberation lag, quantified as the response-weighted delay (RWD), is most affected by the radial depth of the torus, the steepness of the radial cloud distribution, the degree of anisotropy of the AGN radiation field, and the volume filling factor. Nevertheless, we find that the RWD provides a reasonably robust estimate, to within a factor of $\sim 3$, of the luminosity-weighted torus radius, confirming the basic assumption underlying reverberation mapping. However, overall, the models predict radii at $2.2\,\mu$m that are a typically factor of $\sim 2$ larger than those derived from K-band reverberation mapping. This is likely an indication that the innermost region of the torus is populated by clouds dominated by large graphite grains.
- [48] arXiv:2002.12827 [pdf, ps, other]
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Title: Redshift factor and diffusive equilibrium of unbound neutrons in the single nucleus model of accreting neutron star crustComments: To be submitted for publication. Remarks and comments on the present paper will be welcome by the authorsSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
Using a Wigner-Seitz approximation with spherical cells, we re-analyze a widely used single nucleus model of accreting neutron star crust. We calculate beta disequilibrium within the crust, which is sizable, and implies that neutron and baryon chemical potentials, $\mu_n$ and $\mu_{\rm b}$, are not equal. We include also non-equilibrium reactions, driven by matter compression, and proceeding in the reaction layers. The constancy of $e^{\Phi}\mu_n$, where the spacetime metric component $g_{00}=e^{2\Phi}$, in the shells between the reaction layers is not applicable, because single electron captures are blocked, so that the neutron fraction is fixed, and therefore neutrons are not an independent component of the crust matter. The absence of neutron diffusion in the shells between the reaction layers, stems from the constancy of the neutron fraction (concentration) in these shells. In the reaction layers, the outward force resulting from neutron fraction gradient is balanced by the inward gravitational force acting on unbound neutrons. Neglecting the thickness of the reaction layers compared to the shell thickness, we obtain condition $e^{\Phi(r)}f_Q(r)g(r)=$constant, where $g$ is Gibbs energy per nucleon, undergoing discontinuous drops on the reaction surfaces, and $f_Q(r)g(r)={\widetilde{g}}(r)$ is a continuous function, due to the factor $f_Q(r)$ canceling the discontinuities (drops) in $g(r)$. The function $f_Q(r)$ is calculated using the Tolman-Oppenheimer-Volkov equations from $f_Q(P)$ and $g(P)$ obtained from the equation of state (EOS) with discontinuites. The constancy of of $e^{\Phi(r)}{\widetilde{g}}(r)$ is an extension of the standard relation $e^{\Phi(r)}{{\mu}}_{\rm b}(r)=$constant, valid in hydrostatic equilibrium for catalyzed crust.
- [49] arXiv:2002.12834 [pdf, ps, other]
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Title: Repeating fast radio bursts caused by small bodies orbiting a pulsar or a magnetarComments: Submitted to Astronomy and Astrophysics/Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)
Asteroids orbiting into the highly magnetized and highly relativistic wind of a pulsar offer a favorable configuration for repeating fast radio bursts (FRB). The body in direct contact with the wind develops a trail formed of a stationary Alfv{\'e}n wave, called an Alfv\'en wing. When an element of wind crosses the Alfv{\'e}n wing, it sees a rotation of the ambient magnetic field that can cause radio-wave instabilities. In our reference frame, the waves are collimated in a very narrow range of directions, and they have an extremely high intensity. A previous work, published in 2014, showed that planets orbiting a pulsar can cause FRB when they pass in our line of sight. We predicted periodic FRB. Since then random FRB repeaters have been discovered. We present an upgrade of this theory to see if they could be explained by the interaction of smaller bodies with a pulsar wind. Considering the properties of relativistic Alfv{\'e}n wings attached to a body in the pulsar wind, and taking thermal consideration into account (the body must be in solid state) we conduct a parametric study.We find that FRBs can be explained by small size pulsar companions (1 to 10 km) between 0.03 and 1 AU from a pulsar. The intense Lorimer burst (30 Jy) can be explained. Some sets of parameters are also compatible with a magnetar, as suggested for FRB121102. Actually, small bodies orbiting a magnetar could produce (not yet observed) FRBs with $\sim 10^5$ Jy flux density.This model, after the present upgrade, is compatible with the properties discovered since its first publication in 2014, when repeating FRB were still unknown. It is based on standard physics, and on common astrophysical objects that can be found in any kind of galaxy. It requires $10^{10}$ times less power than (common) isotropic-emission FRB models.
- [50] arXiv:2002.12842 [pdf]
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Title: Physically based alternative to the PE criterion for meteoroidsComments: 15 pages, 2 figures, 1 tableSubjects: Earth and Planetary Astrophysics (astro-ph.EP)
Meteoroids impacting the Earth atmosphere are commonly classified using the PE criterion. This criterion was introduced to support the identification of the fireball type by empirically linking its orbital origin and composition characteristics. Additionally, it is used as an indicator of the meteoroid tensile strength and its ability to penetrate the atmosphere. However, the level of classification accuracy of the PE criterion depends on the ability to constrain the value of the input data, retrieved from the fireball observation, required to derive the PE value. To overcome these uncertainties and achieve a greater classification detail we propose a new formulation using scaling laws and dimensionless variables that groups all the input variables into two parameters that are directly obtained from the fireball observations. These two parameters, ${\alpha}$ and ${\beta}$, represent the drag and the mass loss rates along the luminous part of the trajectory, respectively, and are linked to the shape, strength, ablation efficiency, mineralogical nature of the projectile, and duration of the fireball. Thus, the new formulation relies on a physical basis. This work shows the mathematical equivalence between the PE criterion and the logarithm of $2{\alpha}{\beta}$ under the same PE-criterion assumptions. We demonstrate that $log(2{\alpha}{\beta})$ offers a more general formulation which does not require any preliminary constraint on the meteor flight scenario and discuss the suitability of the new formulation for expanding the classification beyond fully disintegrating fireballs to larger impactors including meteorite-dropping fireballs. The reliability of the new formulation is validated using the Prairie Network meteor observations.
- [51] arXiv:2002.12866 [pdf, ps, other]
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Title: Lithium abundances in globular clustersComments: 4 pages, 2 figures, proceedings of the conference "Lithium in the Universe: to Be or not to Be"Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)
Lithium is created during the Big Bang nucleosynthesis and it is destroyed in stellar interiors at relatively low temperatures. However, it should be preserved in the stellar envelopes of unevolved stars and progressively diluted during mixing processes. In particular, after the first dredge-up along the RGB, lithium should be completely destroyed, but this is not what we observe today in globular clusters. This element allows to test stellar evolutionary models, as well as different types of polluters for second population stars in the multiple population scenarios. Due to the difficulty in the measurement of the small available lithium line, few GCs have been studied in details so far. Literature results are not homogeneous for what concerns type of stars, sample sizes, and chemical analysis methods. The Gaia-ESO survey allows us to study the largest sample of GCs stars (about 2000, both dwarfs and giants) for which the lithium has been analysed homogeneously.
- [52] arXiv:2002.12870 [pdf, other]
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Title: Mid-Infrared Diagnostics of the Circumnuclear Environments of the Youngest Radio GalaxiesAuthors: E. Kosmaczewski, L. Stawarz, A. Siemiginowska, C.C. Cheung, L. Ostorero, M. Sobolewska, D. Koziel-Wierzbowska, A. Wojtowicz, V. MarchenkoComments: Submitted to the Astrophysical JournalSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Astrophysics of Galaxies (astro-ph.GA)
We present a systematic analysis of the mid-infrared (MIR) properties of the youngest radio galaxies, based on low-resolution data provided by the {\it WISE} and {\it IRAS} satellites. We restrict our analysis to sources with available X-ray data that constitute the earliest phase of radio galaxy evolution, i.e. those classified as Gigahertz Peaked Spectrum (GPS) and/or Compact Symmetric Objects (CSOs). In our sample of 29 objects, we find that the host galaxies are predominantly red/yellow ellipticals, with some of them displaying distorted morphology. We find a variety of MIR colors, and observe that the sources in which the MIR emission is dominated by the ISM component uniformly populate the region occupied by galaxies with a wide range of pronounced ($\geq 0.5 M_{\odot}$\,yr$^{-1}$) star formation activity. We compare the MIR color distribution in our sample to that in the general population of local AGN, in the population of evolved FR\,II radio galaxies, and also in the population of radio galaxies with recurrent jet activity. We conclude that the triggering of radio jets in AGN does not differentiate between elliptical hosts with substantially different fractions of young stars; instead there is a relationship between the jet duty cycle and the ongoing star formation. The distribution of the sub-sample of our sources with $z<0.4$ on the low-resolution MIR vs. absorption-corrected X-ray luminosity plane is consistent with the distribution of a sample of local AGN. Finally, we comment on the star formation rates of the two $\gamma$-ray detected sources in our sample, 1146+596 \& 1718--649.
- [53] arXiv:2002.12881 [pdf, other]
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Title: Generalized Emergent Dark Energy: observational Hubble data constraints and stability analysisSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc)
Recently \citet{PEDE:2019ApJ} proposed a phenomenologically emergent dark energy (PEDE) which consider that the dark energy density evolves as $\widetilde{\Omega}_{\rm{DE}}(z)\,=\,\Omega_{\rm{DE,0}}\left[ 1 - {\rm{tanh}}\left( {\log}_{10}(1+z) \right) \right]$ with the advantage that it does not have degree of freedom. Later on, \citet{PEDE:2020} proposed a generalized model by adding one degree of freedom to the PEDE model, encoded in the parameter $\Delta$. Motivated by these proposals, we constrain the parameter space ($h,\Omega_m$) and ($h,\Omega_m, \Delta$) for PEDE and Generalized Emergent Dark Energy (GEDE) respectively, by employing the most recent observational (non-) homogeneous Hubble data. Additionally, we reconstruct the deceleration and jerk parameters and estimate yield values at $z=0$ of $q_0 = -0.784^{+0.028}_{-0.027}$ and $j_0 = 1.241^{+0.164}_{-0.149}$ for PEDE and $q_0 = -0.730^{+0.059}_{-0.067}$ and $j_0 = 1.293^{+0.194}_{-0.187}$ for GEDE using the homogeneous sample. We report values on the deceleration-acceleration transition redshift with those reported in the literature within $2\sigma$ CL. Furthermore, we perform a stability analysis of the PEDE and GEDE models to study the global evolution of the Universe around their critical points. Although the PEDE and GEDE dynamics are similar to the standard model, our stability analysis indicates that in both models there is an accelerated phase at early epochs of the Universe.
- [54] arXiv:2002.12891 [pdf, other]
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Title: LARgE Survey -- II. The Dark Matter Halos and the Progenitors and Descendants of Ultra-Massive Passive Galaxies at Cosmic NoonAuthors: Gurpreet Kaur Cheema, Marcin Sawicki, Liz Arcila-Osejo, Anneya Golob, Thibaud Moutard, Stephane Arnouts, Jean CouponComments: Accepted for publication in MNRASSubjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
We use a 27.6 deg$^2$ survey to measure the clustering of $gzK_s$-selected quiescent galaxies at $z\sim1.6$, focusing on ultra-massive quiescent galaxies. We find that $z\sim1.6$ Ultra-Massive Passively Evolving Galaxies (UMPEGs), which have $K_s(AB)<19.75$ (stellar masses of $M_{stars}$ $>\sim 10^{11.4}M_{\odot}$ and mean $<$$M_{stars}$$>$ = $10^{11.5}M_{\odot}$), cluster more strongly than any other known galaxy population at high redshift. Comparing their correlation length, $r_0 = 29.77 \pm 2.75$ $ h^{-1}$Mpc, with the clustering of dark matter halos in the Millennium XXL N-body simulation suggests that these $z\sim1.6$ UMPEGs reside in dark matter halos of mass $M_{h}\sim10^{14.1}h^{-1}M_{\odot}$. Such very massive $z\sim1.6$ halos are associated with the ancestors of $z\sim0$ massive galaxy clusters such as the Virgo and Coma clusters. Given their extreme stellar masses and lack of companions with comparable mass, we surmise that these UMPEGs could be the already-quenched central massive galaxies of their (proto)clusters. We conclude that with only a modest amount of further growth in their stellar mass, $z\sim1.6$ UMPEGs could be the progenitors of some of the massive central galaxies of present-day massive galaxy clusters observed to be already very massive and quiescent near the peak epoch of the cosmic star formation.
- [55] arXiv:2002.12895 [pdf, other]
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Title: An online data analysis system of INTEGRAL telescopeComments: submitted to A&ASubjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); High Energy Astrophysical Phenomena (astro-ph.HE)
In more than 17 years of operation in space INTEGRAL telescope has accumulated large data set that contains records of hard X-ray and soft gamma-ray astronomical sources. These data can be re-used in the context of multi-wavelength or multi-messenger studies of astronomical sources and have to be preserved on long time scales. We present a scientific validation of an interactive online INTEGRAL data analysis system, which generates publication-quality high-level data products: sky images, spectra and light-curves in response to user queries that define analysis parameters, such as source position, time and energy interval and binning. The data products can be requested via a web browser interface or via Application Programming Interface (API). The products for the ISGRI instrument of INTEGRAL are generated using the Offline Science Analysis (OSA) software which is provided by the instrument teams, but reorganized to preserve and re-use intermediate analysis products, ensuring that frequently requested results are available without delay. The platform is portable and can be deployed in any compatible infrastructure. We report the functionalities and performance of the online data analysis system by reproducing the benchmark INTEGRAL results on different types of sources, including bright steady and transient Galactic sources, and bright and weak variable extra-galactic sources. We compare the results obtained with the online data analysis system with previously published results on these sources. We consider the INTEGRAL online data analysis as a demonstrator of more general web-based "data analysis as a service" approach that provides a promising solution for preservation and maintenance of data analysis tools of astronomical telescopes on (multi)decade long time scales and facilitates combination of data in multi-wavelength and multi-messenger studies of astronomical sources.
- [56] arXiv:2002.12922 [pdf, other]
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Title: Building the largest spectroscopic sample of ultra-compact massive galaxies with the Kilo Degree SurveyAuthors: Diana Scognamiglio, Crescenzo Tortora, Marilena Spavone, Chiara Spiniello, Nicola R. Napolitano, Giuseppe D'Ago, Francesco La Barbera, Fedor Getman, Nivya Roy, Maria Angela Raj, Mario Radovich, Massimo Brescia, Stefano Cavuoti, Leon V. E. Koopmans, Koen H. Kuijken, Giuseppe Longo, Carlo Enrico PetrilloSubjects: Astrophysics of Galaxies (astro-ph.GA)
Ultra-compact massive galaxies UCMGs, i.e. galaxies with stellar masses $M_{*} > 8 \times 10^{10} M_{\odot}$ and effective radii $R_{e} < 1.5$ kpc, are very rare systems, in particular at low and intermediate redshifts. Their origin as well as their number density across cosmic time are still under scrutiny, especially because of the paucity of spectroscopically confirmed samples. We have started a systematic census of UCMG candidates within the ESO Kilo Degree Survey, together with a large spectroscopic follow-up campaign to build the largest possible sample of confirmed UCMGs. This is the third paper of the series and the second based on the spectroscopic follow-up program. Here, we present photometrical and structural parameters of 33 new candidates at redshifts $0.15 \lesssim z \lesssim 0.5$ and confirm 19 of them as UCMGs, based on their nominal spectroscopically inferred $M_{*}$ and $R_{e}$. This corresponds to a success rate of $\sim 58\%$, nicely consistent with our previous findings. The addition of these 19 newly confirmed objects, allows us to fully assess the systematics on the system selection, and finally reduce the number density uncertainties. Moreover, putting together the results from our current and past observational campaigns and some literature data, we build the largest sample of UCMGs ever collected, comprising 92 spectroscopically confirmed objects at $0.1 \lesssim z \lesssim 0.5$. This number raises to 116, allowing for a $3\sigma$ tolerance on the $M_{*}$ and $R_{e}$ thresholds for the UCMG definition. For all these galaxies we have estimated the velocity dispersion values at the effective radii which have been used to derive a preliminary mass-velocity dispersion correlation.
- [57] arXiv:2002.12931 [pdf, other]
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Title: Compensated Isocurvature Perturbations in the Galaxy Power SpectrumComments: 17 pages + references and appendix; 6 figures; 1 table. Comments welcomed!Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
We investigate the potential of the galaxy power spectrum to constrain compensated isocurvature perturbations (CIPs), primordial fluctuations in the baryon density that are compensated by fluctuations in CDM density to ensure an unperturbed total matter density. We show that CIPs contribute to the galaxy overdensity at linear order, and if they are close to scale-invariant, their effects are nearly perfectly degenerate with the local PNG parameter $f_{\rm nl}$ if they correlate with the adiabatic perturbations. This degeneracy can however be broken by analyzing multiple galaxy samples with different bias parameters, or by taking CMB priors on $f_{\rm nl}$ into account. Parametrizing the amplitude of the CIP power spectrum as $P_{\sigma\sigma} = A_{\rm CIP}^2P_{\mathcal{R}\mathcal{R}}$ (where $P_{\mathcal{R}\mathcal{R}}$ is the adiabatic power spectrum) we find, for a number of fiducial galaxy samples in a simplified forecast setup, that constraints on $A_{\rm CIP}$, relative to those on $f_{\rm nl}$, of order $\sigma_{A_{\rm CIP}}/\sigma_{f_{\rm nl}} \approx 1-2$ are achievable for CIPs correlated with adiabatic perturbations, and $\sigma_{A_{\rm CIP}}/\sigma_{f_{\rm nl}} \approx 5$ for the uncorrelated case. These values are independent of survey volume, and suggest that current galaxy data are already able to improve significantly on the tightest existing constraints on CIPs from the CMB. Future galaxy surveys that aim to achieve $\sigma_{f_{\rm nl}} \sim 1$ have the potential to place even stronger bounds on CIPs.
Cross-lists for Mon, 2 Mar 20
- [58] arXiv:2002.12534 (cross-list from hep-ph) [pdf, other]
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Title: Current status and muon $g-2$ explanation of lepton portal dark matterComments: 34+21 pages, 12 figures, 3 tablesSubjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Experiment (hep-ex)
In this paper, we summarize phenomenology in lepton portal dark matter (DM) models, where DM couples to leptons and extra leptons/sleptons. There are several possible setups: complex/real scalar DM and Dirac/Majorana fermion DM. In addition, there are choices for the lepton chirality that couples to DM. We discuss the prediction of each model and compare it with the latest experimental constraints from the DM, the LHC, and the flavor experiments. We also propose a simple setup to achieve the discrepancy in the anomalous magnetic moment of muon.
- [59] arXiv:2002.12590 (cross-list from gr-qc) [pdf, other]
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Title: Unveiling the Galileon in a three-body system : scalar and gravitational wave productionComments: 29 pages, 1 figureSubjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Phenomenology (hep-ph)
We consider the prospect of detecting cubic Galileons through their imprint on gravitational wave signals from a triple system. Namely, we consider a massive Black Hole (BH) surrounded by a binary system of two smaller BHs. We assume that the three BHs acquire a conformal coupling to the scalar field whose origin could be due to cosmology or to the galactic environment. In this case, the massive BH has a Vainshtein radius which englobes the smaller ones and suppresses the scalar effects on the motion of the binary system. On the other hand the two binaries can be outside each other's redressed Vainshtein radius calculated in the background of the central BH, allowing for a perturbative treatment of their dynamics. Despite the strong Vainshtein suppression, we find that the scalar effects on the binary system are slightly enhanced with respect to the static case and a significant amount of power can be emitted in the form of the Galileon scalar field, hence actively participating in the inspiralling phase. We compute the modification to the GW phase and show that it can lead to a detectable signal for large enough effective scalar coupling.
- [60] arXiv:2002.12772 (cross-list from gr-qc) [pdf, other]
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Title: A Black Hole inside Dark Matter and the Rotation Curves of GalaxiesComments: 16 pages, 4 figuresSubjects: General Relativity and Quantum Cosmology (gr-qc); Astrophysics of Galaxies (astro-ph.GA)
In this article we find a four-dimensional metric for a large black hole immersed in dark matter. Specifically, we look for and find a static spherically symmetric black hole solution to the Einstein equations which gives, in the Newtonian limit, the rotation curves of galaxies, including the flat region and the Baryonic Tully-Fisher relation, and which has a regular horizon. We obtain as well the energy-momentum tensor of the dark matter sourcing this space-time and it turns, in special, to have a positive mass-energy density everywhere outside the horizon. This black-hole-dark-matter system represents a successful simplified model for galaxies and a new area for exploring the relativistic regime of dark matter.
- [61] arXiv:2002.12779 (cross-list from hep-ph) [pdf, other]
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Title: Dark matter self-interactions from spin-2 mediatorsComments: 5 pages, 2 figures, revtex4 formatSubjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Theory (hep-th)
We propose a new mechanism for making dark matter self-interacting in the presence of a massive spin-2 mediator. The derived Yukawa-type potential for dark matter is independent of the spins of dark matter, so are the resulting Sommerfeld effects for the dark matter self-scattering. We find that both the Born cross section and relatively mild Sommerfeld effects assist to make the self-scattering cross section velocity-dependent. We discuss how to evade the current indirect bounds on dark matter annihilations and show that the model is marginally compatible with perturbative unitarity in the ghost-free realization of the massive spin-2 particle.
- [62] arXiv:2002.12811 (cross-list from gr-qc) [pdf, other]
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Title: Detecting dark matter around black holes with gravitational waves: Effects of dark-matter dynamics on the gravitational waveformComments: 17 pages, 11 figures + appendices. Code available at this https URL (archived at this https URL ), animations available at this https URLSubjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Phenomenology (hep-ph)
A dark matter overdensity around a black hole may significantly alter the dynamics of the black hole's merger with another compact object. We consider here intermediate mass-ratio inspirals of stellar-mass compact objects with intermediate-mass black holes "dressed" with dark matter. We first demonstrate that previous estimates based on a fixed dark-matter dress are unphysical for a range of binaries and dark-matter distributions by showing that the total energy dissipated by the compact object through dynamical friction, as it inspirals through the dense dark matter environment towards the black hole, is larger than the gravitational binding energy of the dark-matter dress itself. We then introduce a new formalism that allows us to self-consistently follow the evolution of the dark-matter dress due to its gravitational interaction with the binary. We show that the dephasing of the gravitational waveform induced by dark matter is smaller than previously thought, but is still potentially detectable with the LISA space interferometer. The gravitational waves from such binaries could provide powerful diagnostics of the particle nature of dark matter.
Replacements for Mon, 2 Mar 20
- [63] arXiv:1901.03260 (replaced) [pdf, ps, other]
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Title: Coherence constraints on physical parameters at bright radio sources and FRB emission mechanismSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); Plasma Physics (physics.plasm-ph)
- [64] arXiv:1901.10666 (replaced) [pdf, ps, other]
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Title: Tidally-Distorted, Iron-Enhanced Exoplanets Closely Orbiting Their StarsComments: Submitted to ApJSubjects: Earth and Planetary Astrophysics (astro-ph.EP)
- [65] arXiv:1903.06517 (replaced) [pdf, other]
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Title: Single Electron-Hole Pair Sensitive Silicon Detector with Surface Event RejectionAuthors: Ziqing Hong, Runze Ren, Noah Kurinsky, Enectali Figueroa-Feliciano, Lise Wills, Suhas Ganjam, Rupak Mahapatra, Nader Mirabolfathi, Brian Nebolsky, H. Douglas Pinckney, Mark PlattComments: 7 pages, 4 figures, Accepted to NIM ASubjects: Instrumentation and Detectors (physics.ins-det); Instrumentation and Methods for Astrophysics (astro-ph.IM)
- [66] arXiv:1904.00133 (replaced) [pdf, other]
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Title: Determining the physical conditions of extremely young Class 0 circumbinary disk around VLA1623AComments: 26 pages, 20 figures, accepted by ApJ 2020.2.27Subjects: Solar and Stellar Astrophysics (astro-ph.SR)
- [67] arXiv:1905.00746 (replaced) [pdf, other]
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Title: On the amount of peculiar velocity field information in supernovae from LSST and beyondComments: v3: revised eq. (13); slightly improved forecasts; references added; accepted for publication in Phys. Dark Univ.; 19 pages, 18 figures. v2: included more optimistic LSST forecasts and extended main results to higher z; included discussion of appropriate kmin; extended discussion; references addedSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Instrumentation and Methods for Astrophysics (astro-ph.IM); General Relativity and Quantum Cosmology (gr-qc)
- [68] arXiv:1905.01612 (replaced) [pdf, other]
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Title: Modelling the tightest relation between galaxy properties and dark matter halo properties from hydrodynamical simulations of galaxy formationAuthors: Jian-hua He (NJU and ICC, Durham)Comments: 12 pages, 10 figures, revised version, accepted for publication in MNRASSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [69] arXiv:1905.03601 (replaced) [pdf, ps, other]
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Title: Einstein-Gauss-Bonnet gravity in 4-dimensional space-timeComments: 6 pages, 1 figure; v3 accepted manuscriptJournal-ref: Phys. Rev. Lett. 124, 081301 (2020)Subjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Theory (hep-th)
- [70] arXiv:1907.10654 (replaced) [pdf, other]
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Title: Modeling rotational disruption of grains and microwave emission from spinning dust in AGB envelopesComments: 14 pages, 9 figures, and 2 tablesSubjects: Astrophysics of Galaxies (astro-ph.GA)
- [71] arXiv:1907.11663 (replaced) [pdf, other]
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Title: Exact analytical expression for the synchrotron radiation spectrum in the Gaussian turbulent magnetic fieldComments: final version published in ApJ. Several changes to the inroduction, minor changes in notationJournal-ref: The Astrophysical Journal, Volume 887, Issue 2, article id. 181, 10 pp. (2019)Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)
- [72] arXiv:1908.09752 (replaced) [pdf, other]
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Title: Lower bound on the primordial black hole merger rateComments: 7 pages, 3 figures, version published in PRDJournal-ref: Phys. Rev. D 101, 043015 (2020)Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Phenomenology (hep-ph)
- [73] arXiv:1908.10352 (replaced) [pdf, other]
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Title: GW170817: Stringent constraints on neutron-star radii from multimessenger observations and nuclear theoryAuthors: Collin D. Capano, Ingo Tews, Stephanie M. Brown, Ben Margalit, Soumi De, Sumit Kumar, Duncan A. Brown, Badri Krishnan, Sanjay ReddyComments: 35 pages, 3 figuresSubjects: High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Phenomenology (hep-ph); Nuclear Theory (nucl-th)
- [74] arXiv:1909.04678 (replaced) [pdf, other]
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Title: Intermediate mass black holes' effect on compact object binariesComments: Accepted for publication in ApJ. 14 pages, 11 figuresSubjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [75] arXiv:1910.04901 (replaced) [pdf, other]
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Title: Dodelson-Widrow Mechanism In the Presence of Self-Interacting NeutrinosComments: 6 pages, 5 figures, matches version published in PRLJournal-ref: Phys. Rev. Lett. 124, 081802 (2020)Subjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [76] arXiv:1910.08027 (replaced) [pdf, other]
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Title: A 3D radiation-hydrodynamic AGB binary modelComments: 21 pages, 8 figures, and 6 tablesSubjects: Solar and Stellar Astrophysics (astro-ph.SR)
- [77] arXiv:1910.09138 (replaced) [pdf, other]
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Title: Multi-waveform inference of gravitational wavesComments: 6 pages, 5 figures, 3 tables, accepted in Phys. Rev. DSubjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Astrophysical Phenomena (astro-ph.HE)
- [78] arXiv:1911.02143 (replaced) [pdf, other]
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Title: Revisiting slow-roll dynamics and the tensor tilt in general single-field inflationComments: 7 pages + appendix, 2 figures, v2: Matches published version in PRD, references addedJournal-ref: Phys. Rev. D 101, 043536 (2020)Subjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Theory (hep-th)
- [79] arXiv:1911.03141 (replaced) [pdf, other]
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Title: GMC Collisions as Triggers of Star Formation. VII. The Effect of Magnetic Field Strength on Star FormationComments: 22 pages, 9 figures, Accepted for publication in ApJSubjects: Astrophysics of Galaxies (astro-ph.GA)
- [80] arXiv:1911.10542 (replaced) [pdf, other]
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Title: The running curvatonComments: 22 pages, 3 figures, comments are welcomeSubjects: 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)
- [81] arXiv:1912.01393 (replaced) [pdf, other]
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Title: Galileon scalar electrodynamicsComments: v2: 25 Pages, 1 figure, added two appendices, Accepted in Phys. Rev. DSubjects: High Energy Physics - Theory (hep-th); Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Phenomenology (hep-ph)
- [82] arXiv:1912.06706 (replaced) [pdf, other]
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Title: Accessibility Measure for Eternal Inflation: Dynamical Criticality and Higgs MetastabilityAuthors: Justin KhouryComments: 40 pages, 2 figures. v2: Minor edits, references addedSubjects: High Energy Physics - Theory (hep-th); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [83] arXiv:2002.01887 (replaced) [pdf, other]
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Title: Modelling the solar transition region using an adaptive conduction methodComments: 20 pages, 9 figures, 1 table, accepted for publication in A&ASubjects: Solar and Stellar Astrophysics (astro-ph.SR)
- [84] arXiv:2002.01956 (replaced) [pdf, other]
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Title: Constraining the Mass of the Emerging Galaxy Cluster SpARCS1049+56 at z=1.71 with Infrared Weak LensingAuthors: Kyle Finner, M. James Jee, Tracy Webb, Gillian Wilson, Saul Perlmutter, Adam Muzzin, Julie Hlavacek-LarrondoComments: 13 pages, 7 figures, Accepted to ApJSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
- [85] arXiv:2002.09493 (replaced) [pdf, other]
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Title: Orbital evidences for dark-matter free Milky-Way dwarf-spheroidal galaxiesAuthors: Francois Hammer, Yanbin Yang, Frederic Arenou, Jianling Wang, Hefan Li, Piercarlo Bonifacio, Carine BabusiauxComments: 16 pages, 6 Figures, accepted for publication in The Astrophysical JournalSubjects: Astrophysics of Galaxies (astro-ph.GA); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Theory (hep-th)
- [86] arXiv:2002.10584 (replaced) [pdf, ps, other]
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Title: Cepheid distances based on Gaia and VMC@VISTA observationsComments: 8 pages, 3 figures, invited talk to appear on Astronomical Society of the Pacific Conference Series "RRLyrae/Cepheid2019: Frontiers of Classical Pulsators: Theory and Observations", Cloudcroft, NM, USA October 13-18, 2019. Corrected typoSubjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA)
- [87] arXiv:2002.11161 (replaced) [pdf, other]
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Title: Low mass planet migration in three dimensional wind-driven inviscid discs: A negative corotation torqueAuthors: Colin P. McNally, Richard P. Nelson, Sijme-Jan Paardekooper, Pablo Benitez-Llambay, Oliver GresselComments: 19 pages, 19 figures, MNRAS accepted, this version fixes typos and arXiv page countSubjects: Earth and Planetary Astrophysics (astro-ph.EP)
- [88] arXiv:2002.11681 (replaced) [pdf, other]
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Title: Magnetic field screening process in a Kerr Black HoleComments: 8 pages, 11 figuresSubjects: High Energy Astrophysical Phenomena (astro-ph.HE)
- [89] arXiv:2002.12296 (replaced) [pdf, other]
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Title: Redshift-space streaming velocity effects on the Lyman-$α$ forest baryon acoustic oscillation scaleComments: 23 pages, 3 figuresSubjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
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