Astrophysics

New submissions

• New submissions
• Cross-lists
• Replacements

New submissions for Wed, 1 Apr 20

[1]  arXiv:2003.13691 [pdf, other]

Title: Inpainting Galactic Foreground Intensity and Polarization maps using Convolutional Neural Network

Authors: Giuseppe Puglisi, Xiran Bai

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

Deep convolutional neural networks have been a popular tool for image generation and restoration. The performance of these networks is related to the capability of learning realistic features from a large dataset. In this work, we applied the problem of inpainting non-Gaussian signal, in the context of Galactic diffuse emissions at the millimetric and sub-millimetric regimes, specifically Synchrotron and Thermal Dust emission. Both of them are affected by contamination at small angular scales due to extra-galactic radio sources (the former) and to dusty star-forming galaxies (the latter). We consider the performances of a nearest-neighbors inpainting technique and compare it with two novels methodologies relying on generative Neural Networks. We show that the generative network is able to reproduce the statistical properties of the ground truth signal more consistently with high confidence level. The Python Inpainter for Cosmological and AStrophysical SOurces (PICASSO) is a package encoding a suite of inpainting methods described in this work and has been made publicly available.

[2]  arXiv:2003.13692 [pdf, other]

Title: Focal Plane Wavefront Sensing with the FAST TGV Coronagraph

Authors: Benjamin Gerard, Christian Marois

Comments: accepted to PASP on March 28, 2020

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

The continual push to directly image exoplanets at lower masses and closer separations orbiting around bright stars remains limited by both quasi-static and residual adaptive optics (AO) aberration. In previous papers we have proposed a modification of the self-coherent camera (SCC) design to address both of these limitations, called the Fast Atmospheric SCC Technique (FAST). In this paper we introduce an additional modification to the FAST focal plane mask design, including the existing Tip/tilt and Gaussian components and adding a charge four Vortex (TGV) component. In addition to boosting SCC fringe signal-to-noise ratio (S/N) as in our previous design, we show that the FAST TGV mask is also optimized to reach high contrast at separations closer to the star. In this paper we use numerical simulations to consider the performance improvement on correcting quasi-static aberration using this new mask compared to the previously proposed Tip/tilt+Gaussian mask. Using active deformable mirror control to generate a calibrated half dark hole improves contrast by a factor of about 200 at 2 - 5 $\lambda/D$ and up to a factor of 10 at 5 - 20 $\lambda/D$. The new methodology presented in this paper, now simultaneously considering both contrast and fringe S/N, opens the door to a new ideology of coronagraph design, where the coronagraph is now considered in duality as both a diffraction attenuator and a wavefront sensor.

[3]  arXiv:2003.13693 [pdf, other]

Title: The Rise and Fall of ASASSN-18pg: Following a TDE from Early To Late Times

Authors: Thomas W.-S. Holoien, Katie Auchettl, Michael A. Tucker, Benjamin J. Shappee, Shannon G. Patel, James C. A. Miller-Jones, Brenna Mockler, Danièl N. Groenewald, Jonathan S. Brown, Christopher S. Kochanek, K. Z. Stanek, Ping Chen, Subo Dong, Jose L. Prieto, Todd A. Thompson, Rachael L. Beaton, Thomas Connor, Philip S. Cowperthwaite, Linnea Dahmen, K. Decker French, Nidia Morrell, David A. H. Buckley, Mariusz Gromadzki, Rupak Roy, David A. Coulter, Georgios Dimitriadis, Ryan J. Foley, Charles D. Kilpatrick, Anthony L. Piro, César Rojas-Bravo, Matthew R. Siebert, Sjoert van Velzen

Comments: 22 pages, 11 figures, 5 tables. Submitted to ApJ. A machine-readable table containing the host-subtracted photometry presented in this manuscript is included as an ancillary file

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

We present nearly 500 days of observations of the tidal disruption event ASASSN-18pg, spanning from 54 days before peak light to 441 days after peak light. Our dataset includes X-ray, UV, and optical photometry, optical spectroscopy, radio observations, and the first published spectropolarimetric observations of a TDE. ASASSN-18pg was discovered on 2018 July 11 by the All-Sky Automated Survey for Supernovae (ASAS-SN) at a distance of $d=78.6$ Mpc, and with a peak UV magnitude of $m\simeq14$ it is both one of the nearest and brightest TDEs discovered to-date. The photometric data allow us to track both the rise to peak and the long-term evolution of the TDE. ASASSN-18pg peaked at a luminosity of $L\simeq2.2\times10^{44}$ erg s$^{-1}$, and its late-time evolution is shallower than a flux $\propto t^{-5/3}$ power-law model, similar to what has been seen in other TDEs. ASASSN-18pg exhibited Balmer lines and spectroscopic features consistent with Bowen fluorescence prior to peak which remained detectable for roughly 225 days after peak. Analysis of the two-component H$\alpha$ profile indicates that, if they are the result of reprocessing of emission from the accretion disk, the different spectroscopic lines may be coming from regions between $\sim10$ and $\sim60$ light-days from the black hole. No X-ray emission is detected from the TDE and there is no evidence of a jet or strong outflow detected in the radio. Our spectropolarimetric observations give no strong evidence for significant asphericity in the emission region, with the emission region having an axis ratio of at least $\sim0.65$.

[4]  arXiv:2003.13694 [pdf, other]

Title: Emergence of an Ultra-Red Ultra-Massive Galaxy Cluster Core at $z=4$

Authors: Arianna S. Long, Asantha Cooray, Jingzhe Ma, Caitlin M. Casey, Julie L. Wardlow, Hooshang Nayyeri, R.J. Ivison, Duncan Farrah, Helmut Dannerbauer

Comments: 15 pages, 7 figures, submitted to ApJ

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

Recent simulations and observations of massive galaxy cluster evolution predict that the majority of stellar mass build up happens within cluster members by $z=2$, before cluster virialization. Protoclusters rich with dusty, star-forming galaxies (DSFGs) at $z>3$ are the favored candidate progenitors for these massive galaxy clusters at $z\sim0$. We present here the first study analyzing stellar emission along with cold dust and gas continuum emission in a spectroscopically confirmed $z=4.002$ protocluster core rich with DSFGs, the Distant Red Core (DRC). We combine new \textit{HST} and \textit{Spitzer} data with existing Gemini, \textit{Herschel}, and ALMA observations to derive individual galaxy-level properties, and compare them to coeval field and other protocluster galaxies. All of the protocluster members are massive ($>10^{10}$ M$_\odot$), but not significantly more so than their coeval field counterparts. Within uncertainty, all are nearly indistinguishable from galaxies on the star-forming vs. stellar mass main-sequence relationship. However, when placed on the star formation efficiency plane, DRC components exhibit starburst-like characteristics with SFRs 10-100$\times$ greater than the expected field value at a given molecular gas mass. Assuming no future major influx of fresh gas, we estimate that these gas poor (f$_\mathrm{gas}<25\%$) yet bursty DSFGs will deplete their gas reservoirs in $<30$ Myr. Using various methodologies, we derive a total $z=4$ halo mass of $\sim10^{14}$ M$_\odot$, and estimate that the DRC will evolve to become an ultra-massive cluster core of mass $\gtrsim10^{15}$ M$_\odot$ by $z=0$.

[5]  arXiv:2003.13696 [pdf, other]

Title: Cosmological Dark Matter: a Review

Authors: M. R. Lovell (University of Iceland)

Comments: 3 pages, 4 figures. Contact: lovell@hi.is

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

Evidence has continued to accumulate over the last few decades as to the existence and nature of dark matter. Depending on the particle candidate, the dark matter can exhibit one of several cosmologically defined models: hot dark matter, cold dark matter, warm dark matter, self-interacting dark matter, and fuzzy dark matter. In this paper I review the relevance and status of these models, whether it is possible for more than one of these models to each constitute some fraction of the dark matter, and discuss the prospects for determining if any of these models can successfully describe the properties and evolution of our own Universe.

[6]  arXiv:2003.13697 [pdf, other]

Title: Angular Momenta, Magnetization, and Accretion of Protostellar Cores

Authors: Aleksandra Kuznetsova, Lee Hartmann, Fabian Heitsch

Comments: 13 pages, 9 figures, accepted by ApJ

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

Building on our previous hydrodynamic study of the angular momenta of cloud cores formed during gravitational collapse of star-forming molecular gas in our previous work, we now examine core properties assuming ideal magnetohydrodynamics (MHD). Using the same sink-patch implementation for the \emph{Athena} MHD code, we characterize the statistical properties of cores, including the mass accretion rates, specific angular momenta, and alignments between the magnetic field and the spin axis of the core on the $0.1 \ \mathrm{pc}$ scale. Our simulations, which reproduce the observed relation between magnetic field strength and gas density, show that magnetic fields can help collimate low density flows and help seed the locations of filamentary structures. Consistent with our previous purely hydrodynamic simulations, stars (sinks) form within the heterogeneous environments of filaments, such that accretion onto cores is highly episodic leading to short-term variability but no long-term monotonic growth of the specific angular momenta. With statistical characterization of protostellar cores properties and behaviors, we aim to provide a starting point for building more realistic and self-consistent disk formation models, helping to address whether magnetic fields can prevent the development of (large) circumstellar disks in the ideal MHD limit.

[7]  arXiv:2003.13698 [pdf, other]

Title: Dark Photon Dark Matter in the Presence of Inhomogeneous Structure

Authors: Samuel J. Witte, Salvador Rosauro-Alcaraz, Samuel D. McDermott, Vivian Poulin

Comments: 30 pages, 11 figures. Ancillary file included to ease reproduction of bound

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

Dark photon dark matter will resonantly convert into visible photons when the dark photon mass is equal to the plasma frequency of the ambient medium. In cosmological contexts, this transition leads to an extremely efficient, albeit short-lived, heating of the surrounding gas. Existing work in this field has been predominantly focused on understanding the implications of these resonant transitions in the limit that the plasma frequency of the Universe can be treated as being perfectly homogeneous, i.e. neglecting inhomogeneities in the electron number density. In this work we focus on the implications of heating from dark photon dark matter in the presence of inhomogeneous structure (which is particularly relevant for dark photons with masses in the range $10^{-15} \lesssim m_{A'} < 10^{-12}$ eV), emphasizing both the importance of inhomogeneous energy injection, as well as the sensitivity of cosmological observations to the inhomogeneities themselves. More specifically, we derive modified constraints on dark photon dark matter from the Ly-$\alpha$ forest, and show that the presence of inhomogeneities allows one to extend constraints to masses outside of the range that would be obtainable in the homogeneous limit, while only slightly relaxing their strength. We then project sensitivity for near-future cosmological surveys that are hoping to measure the 21cm transition in neutral hydrogen prior to reionization, and demonstrate that these experiments will be extremely useful in improving sensitivity to masses near $10^{-14}$ eV, potentially by several orders of magnitude. Finally, we discuss implications for both reionization and early star formation, and show that probes which are inherently sensitive to the inhomogeneous state of the Universe could resolve signatures unique to the light dark photon dark matter scenario, and thus offer a fantastic potential for a positive detection.

[8]  arXiv:2003.13705 [pdf, other]

Title: The Fornax 3D project: Globular clusters tracing kinematics and metallicities

Authors: K. Fahrion, M. Lyubenova, M. Hilker, G. van de Ven, J. Falcón-Barroso, R. Leaman, I. Martín-Navarro, A. Bittner, L. Coccato, E. M. Corsini, D. A. Gadotti, E. Iodice, R. M. McDermid, F. Pinna, M. Sarzi, S. Viaene, P. T. de Zeeuw, L. Zhu

Comments: 13 pages + appendix, accepted for publication in A&A

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

Globular clusters (GCs) are found ubiquitously in massive galaxies and due to their old ages, they are regarded as fossil records of galaxy evolution. Spectroscopic studies of GC systems are often limited to the outskirts of galaxies, where GCs stand out against the galaxy background and serve as bright tracers of galaxy assembly. In this work, we use the capabilities of the Multi Unit Explorer Spectrograph (MUSE) to extract a spectroscopic sample of 722 GCs in the inner regions ($\lesssim 3 R_\text{eff}$) of 32 galaxies in the Fornax cluster. These galaxies were observed as part of the Fornax 3D project, a MUSE survey that targets early and late-type galaxies within the virial radius of Fornax. After accounting for the galaxy background in the GC spectra, we extracted line-of-sight velocities and determined metallicities of a sub-sample of 238 GCs. We found signatures of rotation within GC systems, and comparing the GC kinematics and that of the stellar body shows that the GCs trace the spheroid of the galaxies. While the red GCs prove to closely follow the metallicity profile of the host galaxy, the blue GCs show a large spread of metallicities but they are generally more metal-poor than the host.

[9]  arXiv:2003.13707 [pdf, other]

Title: The Fornax 3D project: Non-linear colour-metallicity relation of globular clusters

Authors: K. Fahrion, M. Lyubenova, M. Hilker, G. van de Ven, J. Falcón-Barroso, R. Leaman, I. Martín-Navarro, A. Bittner, L. Coccato, E. M. Corsini, D. A. Gadotti, E. Iodice, R. M. McDermid, F. Pinna, M. Sarzi, S. Viaene, P. T. de Zeeuw, L. Zhu

Comments: 12 pages + appendix, accepted for publication in A&A

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

Globular cluster (GC) systems of massive galaxies often show a bimodal colour distribution. This has been interpreted as a metallicity bimodality, created by a two-stage galaxy formation where the red, metal-rich GCs were formed in the parent halo and the blue metal-poor GCs were accreted. This interpretation, however, crucially depends on the assumption that GCs are exclusively old stellar systems with a linear colour-metallicity relation (CZR). The shape of the CZR and range of GC ages are currently under debate, because their study requires high quality spectra to derive reliable stellar population properties. We determined metallicities with full spectral fitting from a sample of 187 GCs with high spectral signal-to-noise ratio in 23 galaxies of the Fornax cluster that were observed as part of the Fornax 3D project. The derived CZR from this sample is non-linear and can be described by a piecewise linear function with a break point at ($g - z$) $\sim$ 1.1 mag. The less massive galaxies in our sample ($M_\ast < 10^{10} M_\odot$) appear to have slightly younger GCs, but the shape of the CZR is insensitive to the GC ages. Although the least massive galaxies lack red, metal-rich GCs, a non-linear CZR is found irrespective of the galaxy mass, even in the most massive galaxies ($M_\ast \geq 10^{11} M_\odot$). Our CZR predicts narrow unimodal GC metallicity distributions for low mass and broad unimodal distributions for very massive galaxies, dominated by a metal-poor and metal-rich peak, respectively, and bimodal distributions for galaxies with intermediate masses (10$^{10}$ $\leq$ $M_\ast < 10^{11} M_\odot$) as a consequence of the relative fraction of red and blue GCs. The diverse metallicity distributions challenge the simple differentiation of GC populations solely based on their colour.

[10]  arXiv:2003.13710 [pdf, other]

Title: The deep Chandra survey in the SDSS J1030+0524 field

Authors: R. Nanni, R. Gilli, C. Vignali, M. Mignoli, A. Peca, S. Marchesi, M. Annunziatella, M. Brusa, F. Calura, N. Cappelluti, M. Chiaberge, A. Comastri, K. Iwasawa, G. Lanzuisi, E. Liuzzo, D. Marchesini, I. Prandoni, P. Tozzi, F. Vito, G. Zamorani, C. Norman

Comments: A&A in press, 20 pages, 15 figures. The figures A.2 and and A.3 (postage-stamp images of the catalog) can be found online at: this http URL

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

We present the X-ray source catalog for the 479 ks Chandra exposure of the SDSS J1030+0524 field, that is centered on a region that shows the best evidence to date of an overdensity around a z > 6 quasar, and also includes a galaxy overdensity around a Compton-thick Fanaroff-Riley type II radio galaxy at z = 1.7. Using wavdetect for initial source detection and ACIS Extract for source photometry and significance assessment, we create preliminary catalogs of sources that are detected in the full, soft, and hard bands, respectively. We produce X-ray simulations that mirror our Chandra observation to filter our preliminary catalogs and get a completeness level of > 91% and a reliability level of 95% in each band. The catalogs in the three bands are then matched into a final main catalog of 256 unique sources. Among them, 244, 193, and 208 are detected in the full, soft, and hard bands, respectively. This makes J1030 field the fifth deepest extragalactic X-ray survey to date. The field is part of the Multiwavelength Survey by Yale-Chile (MUSYC), and is also covered by optical imaging data from the Large Binocular Camera (LBC) at the Large Binocular Telescope, near-IR imaging data from the Canada France Hawaii Telescope WIRCam, and Spitzer IRAC. Thanks to its dense multi-wavelength coverage, J1030 represents a legacy field for the study of large-scale structures around distant accreting supermassive black holes. Using a likelihood ratio analysis, we associate multi-band counterparts for 252 (98.4%) of the 256 Chandra sources, with an estimated reliability of 95%. Finally, we compute the cumulative number of sources in each X-ray band, finding that they are in general agreement with the results from the Chandra Deep Fields.

[11]  arXiv:2003.13711 [pdf, other]

Title: Near-infrared variability in dusty white dwarfs: tracing the accretion of planetary material

Authors: Laura K. Rogers, Siyi Xu, Amy Bonsor, Simon Hodgkin, Kate Y. L. Su, Ted von Hippel, Michael Jura

Comments: 14 pages + supplementary figures, 9 figures, accepted for publication in MNRAS

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

The inwards scattering of planetesimals towards white dwarfs is expected to be a stochastic process with variability on human time-scales. The planetesimals tidally disrupt at the Roche radius, producing dusty debris detectable as excess infrared emission. When sufficiently close to the white dwarf, this debris sublimates and accretes on to the white dwarf and pollutes its atmosphere. Studying this infrared emission around polluted white dwarfs can reveal how this planetary material arrives in their atmospheres. We report a near-infrared monitoring campaign of 34 white dwarfs with infrared excesses with the aim to search for variability in the dust emission. Time series photometry of these white dwarfs from the United Kingdom Infrared Telescope (Wide Field Camera) in the J, H and K bands were obtained over baselines of up to three years. We find no statistically significant variation in the dust emission in all three near-infrared bands. Specifically, we can rule out variability at ~1.3% for the 13 white dwarfs brighter than 16th mag in K band, and at ~10% for the 32 white dwarfs brighter than 18th mag over time-scales of three years. Although to date two white dwarfs, SDSS J095904.69-020047.6 and WD 1226+110, have shown K band variability, in our sample we see no evidence of new K band variability at these levels. One interpretation is that the tidal disruption events which lead to large variabilities are rare, occur on short time-scales, and after a few years the white dwarfs return to being stable in the near-infrared.

[12]  arXiv:2003.13717 [pdf, other]

Title: A new set of atmosphere and evolution models for cool T-Y brown dwarfs and giant exoplanets

Authors: Mark W. Phillips, Pascal Tremblin, Isabelle Baraffe, Gilles Chabrier, Nicole F. Allard, Fernand Spiegelman, Jayesh M. Goyal, Ben Drummond, Eric Hebrard

Comments: 21 pages, 18 figures, 1 table. Accepted for publication in A&A. Models available at this http URL and this http URL

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

We present a new set of solar metallicity atmosphere and evolutionary models for very cool brown dwarfs and self-luminous giant exoplanets, which we term ATMO 2020. Atmosphere models are generated with our state-of-the-art 1D radiative-convective equilibrium code ATMO, and are used as surface boundary conditions to calculate the interior structure and evolution of $0.001-0.075\,\mathrm{M_{\odot}}$ objects. Our models include several key improvements to the input physics used in previous models available in the literature. Most notably, the use of a new H-He equation of state including ab initio quantum molecular dynamics calculations has raised the mass by $\sim1-2\%$ at the stellar-substellar boundary and has altered the cooling tracks around the hydrogen and deuterium burning minimum masses. A second key improvement concerns updated molecular opacities in our atmosphere model ATMO, which now contains significantly more line transitions required to accurately capture the opacity in these hot atmospheres. This leads to warmer atmospheric temperature structures, further changing the cooling curves and predicted emission spectra of substellar objects. We present significant improvement for the treatment of the collisionally broadened potassium resonance doublet, and highlight the importance of these lines in shaping the red-optical and near-infrared spectrum of brown dwarfs. We generate three different grids of model simulations, one using equilibrium chemistry and two using non-equilibrium chemistry due to vertical mixing, all three computed self-consistently with the pressure-temperature structure of the atmosphere. We show the impact of vertical mixing on emission spectra and in colour-magnitude diagrams, highlighting how the $3.5-5.5\,\mathrm{\mu m}$ flux window can be used to calibrate vertical mixing in cool T-Y spectral type objects.

[13]  arXiv:2003.13718 [pdf, other]

Title: Optical, X-ray, and $γ$-ray observations of the candidate transitional millisecond pulsar 4FGL J0427.8-6704

Authors: M. R. Kennedy, R. P. Breton, C. J. Clark, V. S. Dhillon, M. Kerr, D. A. H. Buckley, S. B. Potter, D. Mata Sánchez, J. G. Stringer, T. R. Marsh

Comments: 16 pages, 14 figures, accepted for publication in Monthly Notices of the Royal Astronomical Society

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

We present an optical, X-ray, and $\gamma$-ray study of 1SXPS J042749.2-670434, an eclipsing X-ray binary which has an associated $\gamma$-ray counterpart, 4FGL J0427.8-6704. This association has led to the source being classified as a transitional millisecond pulsar (tMSP) in an accreting state. We analyse 10.5 years of Fermi LAT data, and detect a $\gamma$-ray eclipse at the same phase as optical and X-ray eclipses at the >5$\sigma$ level, a significant improvement on the 2.8$\sigma$level of the previous detection. The confirmation of this eclipse solidifies the association between the X-ray source and the $\gamma$-ray source, strengthening the tMSP classification. However, analysis of several optical data sets and an X-ray observation do not reveal a change in the source's median brightness over long timescales or a bi-modality on short timescales. Instead, the light curve is dominated by flickering which has a correlation time of 2.6 min alongside a potential quasi-periodic oscillation at $\sim$21 min. The mass of the primary and secondary star are constrained to be $M_1=1.43^{+0.33}_{-0.19}$ M$_{\odot}$ and $M_2=0.3^{+0.17}_{-0.12}$ M$_{\odot}$ through modelling of the optical light curve. While this is still consistent with a white dwarf primary, we favour the transitional millisecond pulsar in a low accretion state classification due to the significance of the $\gamma$-ray eclipse detection.

[14]  arXiv:2003.13722 [pdf, other]

Title: Defining the Really Habitable Zone

Authors: Marven F. Pedbost, Trillean Pomalgu, Chris Lintott, Nora Eisner, Belinda Nicholson

Comments: Presented without comments

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

Since the discovery of the first confirmed exoplanet, observations have revealed a remarkable diversity of worlds. A wide variety of orbital and physical characteristics are detected in the exoplanet population, and much work has been devoted to deciding which of these planets may be suitable for life. Until now, though, little work has been devoted to deciding which of the potentially habitable planets might actually be \textit{worth} existing on. To this end, we present the Really Habitable Zone (RHZ), defined as the region around a star where acceptable gins and tonic are likely to be abundant. In common with much of the work in the field, we rely throughout on assumptions which are difficult if not impossible to test and present some plots which astronomers can use in their own talks, stripped of all caveats. We suggest that planets in the Really Habitable Zone be early targets for the JWST, because by the time that thing finally launches we're all going to need a drink.

[15]  arXiv:2003.13736 [pdf, other]

Title: Non-dimensional Star-Identification

Authors: Carl Leake, David Arnas, Daniele Mortari

Comments: 14 pages, 17 figures, 4 tables

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Computer Vision and Pattern Recognition (cs.CV)

This study introduces a new "Non-Dimensional" star identification algorithm to reliably identify the stars observed by a wide field-of-view star tracker when the focal length and optical axis offset values are known with poor accuracy. This algorithm is particularly suited to complement nominal lost-in-space algorithms when they fail the star identification due to focal length and/or optical axis offset deviations from their nominal operational ranges. These deviations may be caused, for example, by launch vibrations or thermal variations in orbit. The algorithm performance is compared in terms of accuracy, speed, and robustness to the Pyramid algorithm. These comparisons highlight the clear advantages that a combined approach of these methodologies provides.

[16]  arXiv:2003.13770 [pdf, other]

Title: Frequency stability of the mode spectrum of broad bandwidth Fabry-Perot interferometers

Authors: Jeff Jennings, Ryan Terrien, Connor Fredrick, Michael Grisham, Mark Notcutt, Samuel Halverson, Suvrath Mahadevan, Scott A. Diddams

Comments: 18 pages, 9 figures, submitted to OSA Continuum

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Instrumentation and Detectors (physics.ins-det); Optics (physics.optics)

When illuminated by a white light source, the discrete resonances of a Fabry-Perot interferometer (FP) provide a broad bandwidth, comb-like spectrum useful for frequency calibration. We report on the design, construction and laboratory characterization of two planar, passively stabilized, low finesse (~40) FPs spanning 380 nm to 930 nm and 780 nm to 1300 nm, with nominal free spectral ranges of 20 GHz and 30 GHz respectively. These instruments are intended to calibrate astronomical spectrographs in radial velocity searches for extrasolar planets. By tracking the frequency drift of three widely-separated resonances in each FP we measure fractional frequency drift rates as low as 1 x 10^(-10) / day. However we find that the fractional drift rate varies across the three sample wavelengths, such that the drift of two given resonance modes disagrees with the ratio of their mode numbers. We explore possible causes of this behavior, as well as quantify the temperature and optical power sensitivity of the FPs. Our results demonstrate the advancement of Fabry-Perot interferometers as robust and frequency-stable calibrators for astronomical and other broad bandwidth spectroscopy applications, but also highlight the need for chromatic characterization of these systems.

[17]  arXiv:2003.13780 [pdf, other]

Title: A-priori Validation of Subgrid-scale Models for Astrophysical Turbulence

Authors: Chia-Yu Hu, Chi-Ting Chiang

Comments: 14 pages, 10 figures

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

We perform a-priori validation tests of subgrid-scale (SGS) models for the turbulent transport of momentum, energy and passive scalars. To this end, we conduct two sets of high-resolution hydrodynamical simulations with a Lagrangian code: an isothermal turbulent box with rms Mach number of 0.3, 2 and 8, and the classical wind tunnel where a cold cloud traveling through a hot medium gradually dissolves due to fluid instabilities. Two SGS models are examined: the eddy diffusivity (ED) model wildly adopted in astrophysical simulations and the "gradient model" due to Clark et al. (1979). We find that both models predict the magnitude of the SGS terms equally well (correlation coefficient > 0.8). However, the gradient model provides excellent predictions on the orientation and shape of the SGS terms while the ED model predicts poorly on both, indicating that isotropic diffusion is a poor approximation of the instantaneous turbulent transport. The best-fit coefficient of the gradient model is in the range of [0.16, 0.21] for the momentum transport, and the turbulent Schmidt number and Prandtl number are both close to unity, in the range of [0.92, 1.15].

[18]  arXiv:2003.13789 [pdf, other]

Title: The erratic path to coalescence of LISA massive black hole binaries in sub-pc resolution simulations of smooth circumnuclear gas disks

Authors: Rafael Souza Lima, Lucio Mayer, Pedro R. Capelo, Elisa Bortolas, Thomas R. Quinn

Comments: 28 pages, 16 figures, 1 table, submitted to ApJ

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

We report on high-resolution simulations that explore the orbital decay of massive black hole (MBH) pairs with masses between $10^5$ and $10^7 M_{\odot}$ embedded in a circumnuclear gas disk (CND). An adiabatic equation of state is adopted, with a range of adiabatic indices, which maintains a smooth flow. Mergers between MBHs in this mass range would be detectable by the upcoming Laser Inteferometer Space Antenna (LISA). The orbital evolution is followed from the CND scale ($100$~pc) down to separations of $0.1$--$0.01$~pc at which a circumbinary disk (CBD) could form. The decay is erratic and strongly dependent on the gas flow within the disk, that ultimately determines the net torques experienced by the sinking MBH. Overall, we can identify three different evolutionary stages: (i) an initially slow decay that leads to no significant change in the orbital angular momentum, resulting in some circularization; (ii) a fast migration phase in which the orbital angular momentum decreases rapidly; and (iii) a final, very slow decay phase, in which orbital angular momentum can even increase, and a CBD can form. The fast migration phase owes to disk-driven torques originating primarily from the co-orbital region of the secondary MBH, at a distance of 1--3 Hill radii. We find strong analogies with fast Type III migration for massive planets in protoplanetary disks. The CBD forms only when the decay rate becomes small enough to allow it enough time to carve a cavity around the primary MBH, at scales $\lesssim 1$~pc; when this happens, the MBH separation nearly stalls in our higher-resolution run. We suggest an empirically modified gap-opening criterion that takes into account such timescale effects as well as other deviations from standard assumptions made in the literature. [Abriged]

[19]  arXiv:2003.13796 [pdf, other]

Title: Robustly detecting changes in warm Jupiters' transit impact parameters

Authors: Rebekah I. Dawson

Comments: Accepted by AJ

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

Torques from a mutually inclined perturber can change a transiting planet's impact parameter, resulting in variations in the transit shape and duration. Detection of and upper limits on changes in impact parameter yield valuable constraints on a planetary system's three dimensional architecture. Constraints for warm Jupiters are particularly interesting because they allow us to test origins theories that invoke a mutually inclined perturber. Because of warm Jupiters' high signal-to-noise transits, changes in impact parameter are feasible to detect. However, here we show that allowing the impact parameter to vary uniformly and independently from transit to transit leads to incorrect inferences about the change, propagating to incorrect inferences about the perturber. We demonstrate that an appropriate prior on the change in impact parameter mitigates this problem. We apply our approach to eight systems from the literature and find evidence for changes in impact parameter for warm Jupiter Kepler-46b. We conclude with our recommendations for light curve fitting, including when to fit impact parameters vs. transit durations.

[20]  arXiv:2003.13800 [pdf, other]

Title: X-ray emission from He II 1640 emitting galaxies in VANDELS

Authors: A. Saxena (1, 2), L. Pentericci (1), D. Schaerer, R. Schneider, R. Amorin, A. Bongiorno, A. Calabrò, M. Castellano, A. Cimatti, F. Cullen, A. Fontana, J. P. U. Fynbo, N.Hathi, D. J. McLeod, M. Talia, G. Zamorani ((1) INAF-OAR, (2) University College London)

Comments: 10 pages, 4 figures, submitted to MNRAS. Comments welcome!

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

We present X-ray measurements for 18 star-forming galaxies showing He II $\lambda 1640$ emission at $z\sim2.2-5$ in the Chandra Deep Field South, to test whether they show any X-ray excess compared to galaxies with no He II emission. Using aperture photometry on the 7 Ms Chandra image, we find that even though He II emitting galaxies in our sample (especially those with FWHM(He II) < 1000 km~s$^{-1}$) have marginally higher X-ray emission than galaxies with no He II, the difference is not statistically significant. The X-ray luminosity per star formation rate ($L_X$/SFR) for He II emitters and non-emitters are comparable, which rules out any enhanced contribution from young X-ray sources. The $L_X$/SFR at $z\sim3$ for both He II emitters and non-emitters is consistent with observations at lower redshifts, and in line with the redshift evolution predicted by models. We also find that our $L_X$/SFR measurements are consistent with the metallicity dependence predicted and observed in the literature. Therefore, we conclude that there is no significant difference between the X-ray emission from galaxies with and without He II emission, which rules out enhanced contribution from XRBs or weak or obscured AGN in galaxies with strong He II at $z\sim3$. Given the other similarities in the physical properties of both He II emitters and non-emitters reported earlier, alternative sources of He II ionising photon production, such as localised low-metallicity stellar populations, Pop-III stars, etc. may need to be explored.

[21]  arXiv:2003.13804 [pdf, other]

Title: Thermophysical modelling and parameter estimation of small solar system bodies via data assimilation

Authors: M. Hamm, I. Pelivan, M. Grott, J. de Wiljes

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Earth and Planetary Astrophysics (astro-ph.EP); Numerical Analysis (math.NA); Optimization and Control (math.OC)

Deriving thermophysical properties such as thermal inertia from thermal infrared observations provides useful insights into the structure of the surface material on planetary bodies. The estimation of these properties is usually done by fitting temperature variations calculated by thermophysical models to infrared observations. For multiple free model parameters, traditional methods such as Least-Squares fitting or Markov-Chain Monte-Carlo methods become computationally too expensive. Consequently, the simultaneous estimation of several thermophysical parameters together with their corresponding uncertainties and correlations is often not computationally feasible and the analysis is usually reduced to fitting one or two parameters. Data assimilation methods have been shown to be robust while sufficiently accurate and computationally affordable even for a large number of parameters. This paper will introduce a standard sequential data assimilation method, the Ensemble Square Root Filter, to thermophysical modelling of asteroid surfaces. This method is used to re-analyse infrared observations of the MARA instrument, which measured the diurnal temperature variation of a single boulder on the surface of near-Earth asteroid (162173) Ryugu. The thermal inertia is estimated to be $295 \pm 18$ $\mathrm{J\,m^{-2}\,K^{-1}\,s^{-1/2}}$, while all five free parameters of the initial analysis are varied and estimated simultaneously. Based on this thermal inertia estimate the thermal conductivity of the boulder is estimated to be between 0.07 and 0.12 $\mathrm{W\,m^{-1}\,K^{-1}}$ and the porosity to be between 0.30 and 0.52. For the first time in thermophysical parameter derivation, correlations and uncertainties of all free model parameters are incorporated in the estimation procedure and thus, results are more accurate than previously derived parameters.

[22]  arXiv:2003.13836 [pdf, other]

Title: Classification and Evolution of Galaxies According to the Dynamical State of Host Clusters and Galaxy Luminosities

Authors: D. F. Morell, A. L. B. Ribeiro, R. R. de Carvalho, S. B. Rembold, P. A. A. Lopes, A. P. Costa

Comments: Accepted for publication in MNRAS

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

We analyze the dependence of galaxy evolution on cluster dynamical state and galaxy luminosities for a sample of 146 galaxy clusters from the Yang SDSS catalog. Clusters were split according to their velocity distribution in Gaussians (G) and Non-Gaussians (NG), and further divided by luminosity regime. We performed a classification in the Age-SSFR plane providing three classes: star-forming (SF), passive (PAS), and intermediate (GV -- green valley). We show that galaxies evolve in the same way in G and NG systems, but also suggest that their formation histories leads to different mixtures of galactic types and infall patterns. Separating the GV into star-forming and passive components, we find more bright galaxies in the passive mode of NG than in G systems. We also find more intermediate faint galaxies in the star-forming component of NG than in G systems. Our results suggest the GV as the stage where the transition from types Sab and Scd to S0 must be taking place, but the conversion between morphological types is independent of the dynamical stage of the clusters. Analyzing the velocity dispersion profiles, we find that objects recently infalling in clusters have a different composition between G and NG systems. While all galaxy types infall onto G systems, Sab and Scd dominate the infall onto NG systems. Finally, we find that faint Scd in the outskirts of NG systems present higher asymmetries relative to the mean asymmetry of field galaxies, suggesting environmental effects acting on these objects.

[23]  arXiv:2003.13851 [pdf, other]

Title: Differential rotation in neutron stars with open and closed magnetic topologies

Authors: F. Anzuini, A. Melatos

Comments: MNRAS accepted. 15 pages, 17 figures

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

Analytic arguments have been advanced that the degree of differential rotation in a neutron star depends on whether the topology of the internal magnetic field is open or closed. To test this assertion, the ideal-magnetohydrodynamics solver PLUTO is employed to investigate numerically the flow of an incompressible, viscous fluid threaded by a magnetic field with open and closed topologies in a conducting, differentially rotating, spherical shell. Rigid body corotation with the outer sphere is enforced on the Alfv\'en time-scale, along magnetic field lines that connect the northern and southern hemispheres of the outer sphere. Along other field lines, however, the behavior is more complicated. For example, an initial point dipole field evolves to produce an approximately closed equatorial flux tube containing at least one predominantly toroidal and approximately closed field line surrounded by a bundle of predominantly toroidal but open field lines. Inside the equatorial flux tube, the field-line-averaged magnetic tension approaches zero, and the fluid rotates differentially, adjusting its angular velocity on the viscous time-scale to match the boundary conditions on the flux tube's toroidal surface. Outside the equatorial flux tube the differential rotation increases, as the magnetic tension averaged along open field lines decreases.

[24]  arXiv:2003.13864 [pdf, other]

Title: Retrograde-rotating exoplanets experience obliquity excitations in an eccentricity-enabled resonance

Authors: Steven M. Kreyche, Jason W. Barnes, Billy L. Quarles, Jack J. Lissauer, John E. Chambers, Matthew M. Hedman

Comments: Accepted to The Planetary Science Journal. Figure 2 and Figure 4b are intended to be animated figures; please email the first author for the associated video files

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

Previous studies have shown that planets that rotate retrograde (backwards with respect to their orbital motion) generally experience less severe obliquity variations than those that rotate prograde (the same direction as their orbital motion). Here we examine retrograde-rotating planets on eccentric orbits and find a previously unknown secular spin-orbit resonance that can drive significant obliquity variations. This resonance occurs when the frequency of the planet's rotation axis precession becomes commensurate with an orbital eigenfrequency of the planetary system. The planet's eccentricity enables a participating orbital frequency through an interaction in which the apsidal precession of the planet's orbit causes a cyclic nutation of the planet's orbital angular momentum vector. The resulting orbital frequency follows the relationship $f = 2 \dot{\varpi} - \dot{\Omega}$, where $\dot{\varpi}$ and $\dot{\Omega}$ are the rates of the planet's changing longitude of periapsis and ascending node, respectively. We test this mechanism by simulating cases of a simple Earth-Jupiter system, and confirm the predicted resonance. Over the course of 100 Myr, the test Earths with rotation axis precession rates near the predicted resonant frequency experienced pronounced obliquity variations of order $10^\circ$-$30^\circ$. These variations can be significant, and suggest that while retrograde rotation is a stabilizing influence most of the time, retrograde rotators can experience large obliquity variations if they are on eccentric orbits and enter this spin-orbit resonance.

[25]  arXiv:2003.13871 [pdf, other]

Title: The ancient main-sequence solar proxy HIP 102152 unveils the activity and rotational fate of our Sun

Authors: Diego Lorenzo-Oliveira, Jorge Meléndez, Geisa Ponte, Jhon Yana Galarza

Comments: Accepted for publication in MNRAS Letters

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

We present a detailed analysis of the possible future Sun's rotational evolution scenario based on the 8 Gyr-old solar twin HIP 102152. Using HARPS high-cadence observations (and TESS light curves), we analyzed the modulation of a variety of activity proxies (Ca II, HI Balmer, and Na I lines), finding a strong rotational signal of 35.7 $\pm$ 1.4 days ($\log B_{\rm factor}\sim70$, in the case of Ca II K line). This value matches with the theoretical expectations regarding the smooth rotational evolution of the Sun towards the end of the main-sequence, validating the use of gyrochronology after solar age.

[26]  arXiv:2003.13879 [pdf, other]

Title: Making It Rain: How Giving Me Telescope Time Can Reduce Drought

Authors: Michael B. Lund

Comments: 8 pages, 3 figures, 3 tables. Submitted to Acta Prima Aprilia

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Popular Physics (physics.pop-ph)

In this paper we assess the correlation between recent observing runs (2018 and 2019) and inclement weather, and demonstrate that these observing runs have seen much more rainfall than would otherwise be expected, an increase of over 200%. We further look at a number of observatory sites in areas that are facing or will face drought, and suggest that a strong environmental benefit would follow from telescope allocation committees providing us an inordinate amount of telescope time at facilities located around the globe.

[27]  arXiv:2003.13884 [pdf, ps, other]

Title: SOFIA-EXES Observations of Betelgeuse during the Great Dimming of 2019/2020

Authors: Graham M. Harper, Curtis N. DeWitt, Matthew J. Richter, Edward F. Guinan, Richard Wasatonic, Nils Ryde, Edward, J. Montiel, Amanda J. Townsend

Comments: 20 pages, 5 figures, ApJL Accepted

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

In 2019 October Betelgeuse began a decline in V-band brightness that went beyond the minimum expected from its quasi-periodic ~420 day cycle, becoming the faintest in recorded photometric history. Observations obtained in 2019 December with VLT/SPHERE (Montarges 2020) have shown that the southern half of the star has become markedly fainter than in 2019 January indicating that a major change has occurred in, or near, the photosphere.
We present SOFIA-EXES high spectral-resolution observations of [Fe II] 25.99 mic and [S I] 25.25 mic emission lines from Betelgeuse obtained during the unprecedented 2020 February V-band brightness minimum to investigate potential changes in the circumstellar flow. These spectra are compared to observations obtained in 2015 and 2017 when the V magnitude was typical of brighter phases. We find only very small changes in the gas velocities reflected by either of the line profiles, no significant changes in the flux to continuum ratios, and hence no significant changes in the [Fe II]/[S I] flux ratios. There is evidence that absorption features have appeared in the 2020 continuum.
The Alfven wave-crossing time from the upper-photosphere is sufficiently long that one would not expect a change in the large scale magnetic field to reach the circumstellar [Fe II] and [S I] line forming regions, 3 < R(R*) < 20. However, the light-crossing time is of order a few hours and a reduction in luminosity may reduce the dust-gas heating rate and [O I] 63.19 mic emission which has contributions from R > 20R*, where significant circumstellar oxygen-rich dust is observed.

[28]  arXiv:2003.13889 [pdf, other]

Title: EAGLE and Illustris-TNG predictions for resolved eROSITA X-ray observations of the circumgalactic medium around normal galaxies

Authors: Benjamin D. Oppenheimer, Akos Bogdan, Robert A. Crain, John A. ZuHone, William R. Forman, Joop Schaye, Nastasha A. Wijers, Jonathan J. Davies, Christine Jones, Ralph P. Kraft, Vittorio Ghirardini

Comments: 10 pages, 4 figures, 1 table, Accepted ApJL

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

We simulate stacked observations of nearby hot X-ray coronae associated with galaxies in the EAGLE and Illustris-TNG hydrodynamic simulations. A forward modeling pipeline is developed to predict 4-year eROSITA observations and stacked image analysis, including the effects of instrumental and astrophysical backgrounds. We propose an experiment to stack z~0.01 galaxies separated by specific star-formation rate (sSFR) to examine how the hot (T>=10^6 K) circumgalactic medium (CGM) differs for high- and low-sSFR galaxies. The simulations indicate that the hot CGM of low-mass (M_*~10^{10.5} Msol), high-sSFR (defined as the top one-third ranked by sSFR) central galaxies will be detectable to a galactocentric radius r~30-50 kpc. Both simulations predict lower luminosities at fixed stellar mass for the low-sSFR galaxies (the lower third of sSFR) with Illustris-TNG predicting 3x brighter coronae around high-sSFR galaxies than EAGLE. Both simulations predict detectable emission out to r~150-200 kpc for stacks centered on high-mass (M_*~10^{11.0} Msol) galaxies, with EAGLE predicting brighter X-ray halos. The extended soft X-ray luminosity correlates strongly and positively with the mass of circumgalactic gas within the virial radius (f_{CGM}). Prior analyses of both simulations have established that f_{CGM} is reduced by expulsive feedback driven mainly by black hole growth, which quenches galaxy growth by inhibiting replenishment of the ISM. Both simulations predict that eROSITA stacks should not only conclusively detect and resolve the hot CGM around L^* galaxies for the first time, but provide a powerful probe of how the baryon cycle operates, for which there remains an absence of consensus between state-of-the-art simulations.

[29]  arXiv:2003.13891 [pdf, ps, other]

Title: LAMOST J040643.69+542347.8: the fastest Rotator in the Galaxy

Authors: Guang-Wei Li

Comments: 7 pages, 3 figures, 1 table. Accepted by the ApJ Letter

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

Rotation and binary interaction play important roles in understanding the nature of massive stars (>8 Msun). Some interesting transients, such as the long-duration gamma-ray bursts, are thought to be originated from fast-rotating massive stars. Because the strong stellar wind can effectively spin down a metal-rich massive star with fast rotation, it is very hard to find single massive stars rotating critically in the Galaxy. In the present work reported is the discovery of the fastest rotator in the Galaxy, LAMOST J040643.69+542347.8, with a projected rotational velocity vsini ~540 km/s, which is ~ 100 km/s faster than that of the previous record holder HD 191423. The star has a spectral type of O6.5 Vnnn(f)p. Its He I 4471 absorption line is blueshifted and asymmetric, while its He II 4686 and Ha have central absorption reversals in their emissions. It is also a runaway star, which implies an origin in a close binary interaction. Compared to VFTS 285 and VFTS 102 (their vsini ~ 610 km/s) in the Large Magellanic Cloud, LAMOST J040643.69+542347.8 has its own peculiar spectral characteristics and earlier spectral type. Moreover, LAMOST J040643.69+542347.8 is bright (B ~ 13.9 mag) enough to allow future high-resolution spectroscopic follow-ups.

[30]  arXiv:2003.13915 [pdf, other]

Title: What Makes Ly$α$ Nebulae Glow? Mapping the Polarization of LABd05

Authors: Eunchong Kim, Yujin Yang, Ann Zabludoff, Paul Smith, Buell Jannuzi, Myung Gyoon Lee, Narae Hwang, Byeong-Gon Park

Comments: 11 pages, 8 figures

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

"Ly$\alpha$ nebulae" are giant ($\sim$100 kpc), glowing gas clouds in the distant universe. The origin of their extended Ly$\alpha$ emission remains a mystery. Some models posit that Ly$\alpha$ emission is produced when the cloud is photoionized by UV emission from embedded or nearby sources, while others suggest that the Ly$\alpha$ photons originate from an embedded galaxy or AGN and are then resonantly scattered by the cloud. At least in the latter scenario, the observed Ly$\alpha$ emission will be polarized. To test these possibilities, we are conducting imaging polarimetric observations of seven Ly$\alpha$ nebulae. Here we present our results for LABd05, a cloud at $z$ = 2.656 with an obscured, embedded AGN to the northeast of the peak of Ly$\alpha$ emission. We detect significant polarization. The highest polarization fractions $P$ are $\sim$10-20% at $\sim$20-40 kpc southeast of the Ly$\alpha$ peak, away from the AGN. The lowest $P$, including upper-limits, are $\sim$5% and lie between the Ly$\alpha$ peak and AGN. In other words, the polarization map is lopsided, with $P$ increasing from the Ly$\alpha$ peak to the southeast. The measured polarization angles $\theta$ are oriented northeast, roughly perpendicular to the $P$ gradient. This unique polarization pattern suggests that 1) the spatially-offset AGN is photoionizing nearby gas and 2) escaping Ly$\alpha$ photons are scattered by the nebula at larger radii and into our sightline, producing tangentially-oriented, radially-increasing polarization away from the photoionized region. Finally we conclude that the interplay between the gas density and ionization profiles produces the observed central peak in the Ly$\alpha$ emission. This also implies that the structure of LABd05 is more complex than assumed by current theoretical spherical or cylindrical models.

[31]  arXiv:2003.13918 [pdf, other]

Title: Resolving Exo-Continents with Einstein Ring Deconvolution

Authors: Alexander Madurowicz

Comments: 17 pages, 10 figures. Please do not print this document

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

A mission to the focus of the solar gravitational lens could produce images with unprecedented angular resolution and sensitivity. In the context of trying to resolve the time variable thermal signature of continents on other Earth-like exoplanets, we develop an approach to improve the image reconstruction performance by using azimuthal variations in the Einstein Ring's intensity. In the first post-Newtonian approximation to General Relativity, an arbitrary disk intensity distribution in the source plane is mapped to a narrow annulus around the Einstein Ring, with each azimuthal element corresponding to a sector in the disk. A matrix-based linear measurement model at various fixed signal-to-noise ratios demonstrates that this extra information is useful in improving the reconstruction when the image is sparsely sampled, which could improve integration times and temporal errors. Various issues and future outlooks are discussed.

[32]  arXiv:2003.13925 [pdf, ps, other]

Title: Massive star formation in the Carina nebula complex and Gum 31 -- I. The Carina nebula complex

Authors: Shinji Fujita, Hidetoshi Sano, Rei Enokiya, Katsuhiro Hayashi, Mikito Kohno, Kisetsu Tsuge, Kengo Tachihara, Atsushi Nishimura, Akio Ohama, Yumiko Yamane, Takahiro Ohno, Rin Yamada, Yasuo Fukui

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

Herein, we present results from observations of the 12CO (J=1-0), 13CO (J=1-0), and 12CO (J=2-1) emission lines toward the Carina nebula complex (CNC) obtained with the Mopra and NANTEN2 telescopes. We focused on massive-star-forming regions associated with the CNC including the three star clusters Tr14, Tr15, and Tr16, and the isolated WR-star HD92740. We found that the molecular clouds in the CNC are separated into mainly four clouds at velocities -27, -20, -14, and -8 km/s. Their masses are 0.7x10^4Msun, 5.0x10^4 Msun, 1.6x10^4 Msun, and 0.7x10^4 Msun, respectively. Most are likely associated with the star clusters, because of their high 12CO (J=2-1)/12CO (J=1-0) intensity ratios and their correspondence to the Spitzer 8 micron distributions. In addition, these clouds show the observational signatures of cloud--cloud collisions. In particular, there is a V-shaped structure in the position--velocity diagram and a complementary spatial distribution between the -20 km/s cloud and the -14 km/s cloud. Based on these observational signatures, we propose a scenario wherein the formation of massive stars in the clusters was triggered by a collision between the two clouds. By using the path length of the collision and the assumed velocity separation, we estimate the timescale of the collision to be ~1 Myr. This is comparable to the ages of the clusters estimated in previous studies.

[33]  arXiv:2003.13928 [pdf, ps, other]

Title: Machine Learning for the Gravitational Wave Observation with Pulsar Timing Array

Authors: Jin Li, MengNi Chen, Yi Feng, Di Li, Yuanhong Zhong

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

Pulsar timing arrays (PTAs) have been proven as one of the most potential approaches to detect low-frequency gravitational waves in the near future. Although PTAs have not captured any GW signals at present, there have been a large number of related theoretical researches and some meaningful detection limits. In this paper, we focus on the nanohertz gravitational waves (GWs) from individual supermassive binary black holes (SMBBHs). Given a specific pulsar PSR J1909$-$3744, the corresponding GW$-$induced timing residuals in PTAs with Gaussian white noise can be simulated. Then we present the classification of simulated PTA data and parameter estimation for potential GW sources using machine learning based on neural networks. As a classifier, the convolutional neural network (CNN) shows a great performance when the signal to noise ratio $\geq$7 (the corresponding dimensionless amplitude of GW is $h\geq 2\times 10^{-15}$). On the other hand, we apply recurrent neural network (RNN) and Bayesian neural networks (BNN) to chirp mass ($\mathcal{M}$) estimation, which are able to provide the mean relative error and uncertainties of $\mathcal{M}$. That is crucial to astrophysical observation. In our case, the mean relative error of chirp mass estimation is less than $15\%$ with PTA sensitivity. Although these results are achieved for simulated PTA data, it's important for realizing intelligent processing on PTA data analysis.

[34]  arXiv:2003.13953 [pdf, other]

Title: The warm-hot, extended, massive circumgalactic medium of NGC 3221: an XMM-Newton discovery

Authors: Sanskriti Das, Smita Mathur, Anjali Gupta

Comments: 9 pages, 5 figures, submitted to ApJL

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

Using Suzaku data, we had found a $3.4\sigma$ evidence for the warm-hot circumgalactic medium (CGM) in the L$^\star$ galaxy NGC 3221. Here we present XMM-Newton data and outline an efficient, rigorous and well-defined method to extract the faint CGM signal. We confirm the CGM detection at $>4\sigma$ significance within 30--200 kpc of the galaxy. We claim with $99.62\%$ confidence that the CGM is extended beyond $150$ kpc. The average temperature of the CGM is 2.0$^{+0.2}_{-0.3} \times 10^6$ K, but it is not isothermal. We find suggestive evidence for a declining temperature gradient out to 125 kpc and for super-virial temperature within 100 kpc. While a super-virial temperature component has been detected in the Milky Way CGM, this is the first time a temperature gradient has been observed in the warm-hot CGM of any spiral galaxy. The emission measure profile is well-fit with either a $\beta-$ model or a constant density profile. Deeper data are required to constrain the temperature and density profiles. We also confirm the Suzaku result that the warm-hot CGM is the most massive baryon component of NGC 3221.

[35]  arXiv:2003.13974 [pdf, other]

Title: A study on the statistical significance of mutual information between morphology of a galaxy and its large-scale environment

Authors: Suman Sarkar, Biswajit Pandey

Comments: 13 pages, 6 figures, 3 tables. Any comments or suggestions are welcome

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

A non-zero mutual information between morphology of a galaxy and its large-scale environment is known to exist in SDSS upto a few tens of Mpc. It is important to test the statistical significance of these mutual information if any. We propose three different methods to test the statistical significance of these non-zero mutual information and apply them to SDSS and Millennium Run simulation. We randomize the morphological information of SDSS galaxies without affecting their spatial distribution and compare the mutual information in the original and randomized datasets. We also divide the galaxy distribution into smaller subcubes and randomly shuffle them many times keeping the morphological information of galaxies intact. We compare the mutual information in the original SDSS data and its shuffled realizations for different shuffling lengths. Using a t-test, we find that a statistically significant (at 99.9% confidence level) mutual information between morphology and environment exists upto the entire length scale probed. We also conduct another experiment using mock datasets from a semi-analytic galaxy catalogue where we assign morphology to galaxies in a controlled manner based on the density at their locations. The experiment clearly demonstrate that mutual information can effectively capture the physical correlations between morphology and environment. Our analysis suggests that physical association between morphology and environment may extend to much larger length scales than currently believed and mutual information can be used as an useful statistical measure for the study of large-scale environmental dependence of galaxy properties.

[36]  arXiv:2003.13994 [pdf, ps, other]

Title: Investigation of the parameters of spiral pattern in galaxies: the arm width

Authors: Aleksandr Mosenkov, Sergey Savchenko, Alexander Marchuk

Comments: 6 pages, 6 figures, Accepted for publication in Research in Astronomy and Astrophysics

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

In this work we determine the parameters of spiral structure for a sample of face-on spiral galaxies. In practice, the solution of this problem is a hard task because of the diversity of the observed characteristics of spiral structure, such as the arm number, their shape, arm contrast etc. In this work we study spiral structure in galaxies based on an analysis of photometric cuts perpendicular to the arm direction. The method is based on an approximation of these slices with an analytical function and derivation of the parameters of spiral structure (arm width, asymmetry, pitch angle) using the fitted parameters of this approximation. The algorithm has been applied to a sample of 155 galaxies selected from the Sloan Digital Sky Survey in different passbands. In this paper we only consider the results on the arm width: most spirals show an increase of their width with galactocentric distance. Only 14 per cent of galaxies in our sample show an opposite trend or have an almost constant arm width at all radii.

[37]  arXiv:2003.13998 [pdf, ps, other]

Title: Site-testing at Muztagh-ata site II: Seeing statistics

Authors: Jing Xu, Ali Esamdin, Jin-xin Hao, Jin-min Bai, Ji Yang, Xu Zhou, Yong-qiang Yao, Jin-liang Hou, Guang-xin Pu, Guo-jie Feng, Chun-hai Bai, Peng Wei, Shu-guo Ma, Abudusaimaitijiang Yisikandee, Le-tian Wang, Xuan Zhang, Liang Ming, Lu Ma, Jin-zhong Liu, Zi-huang Cao, Yong-heng Zhao, Lu Feng, Jian-rong Shi, Hua-lin Chen, Chong Pei, Xiao-jun Jiang, Jian-feng Wang, Jian-feng Tian, Yan-jie Xue, Jing-yao Hu, Yun-ying Jiang

Comments: 13 pages, 16 figures

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

In this article, we present a detailed analysis of the statistical properties of seeing for the Muztagh-ata site which is the candidate site for hosting future Chinese Large Optical/infrared Telescope (LOT) project. The measurement was obtained with Differential Image Motion Monitor (DIMM) from April 2017 to November 2018 at different heights during different periods. The median seeing at 11 meters and 6 meters are very close but different significantly from that on the ground. We mainly analyzed the seeing at 11 meters monthly and hourly, having found that the best season for observing was from late autumn to early winter and seeing tended to improve during the night only in autumn. The analysis of the dependence on temperature inversion, wind speed, direction also was made and the best meteorological conditions for seeing is given.

[38]  arXiv:2003.14019 [pdf, other]

Title: Pulsing and Non-Pulsing ULXs: the Iceberg Emerges

Authors: Andrew King, Jean-Pierre Lasota

Comments: 6 pages, 2 figures, 2 tables. MNRAS in press

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

We show that ultraluminous X-ray sources (ULXs) with coherent X-ray pulsing (PULXs) probably have neutron-star spin axes significantly misaligned from their central accretion discs. Scattering in the funnels collimating their emission and producing their apparent super-Eddington luminosities is the most likely origin of the observed correlation between pulse fraction and X-ray photon energy. Pulsing is suppressed in systems with the neutron-star spin closely aligned to the inner disc, explaining why some ULXs show cyclotron features indicating strong magnetic fields, but do not pulse. We suggest that alignment (or conceivably, field suppression through accretion) generally occurs within a fairly short fraction of the ULX lifetime, so that most neutron-star ULXs become unpulsed. As a result we further suggest that almost all ULXs actually have neutron-star accretors, rather than black holes or white dwarfs, reflecting their progenitor high-mass X-ray binary and supersoft X-ray source populations.

[39]  arXiv:2003.14036 [pdf, ps, other]

Title: Far-infrared nebular spectral features from growing massive black holes

Authors: Evgenii O. Vasiliev, Yuri A. Shchekinov, Biman B. Nath

Comments: 15 pages, 13 figures, submitted to MNRAS, comments welcome

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

Supermassive black holes (BHs) and their host galaxies are interlinked by virtue of feedbacks and are thought to be co-eval across the Hubble time. This relation is highlighted by an approximate proportionality between the BH mass $M_\bullet$ and the mass of a stellar bulge $M_\ast$ of the host galaxy. However, a large spread of the ratio $M_\bullet/M_\ast$ and a considerable excess of BH mass at redshifts $z\sim8$, indicate that the coevolution of central massive BHs and stellar populations in host galaxies may have experienced variations in its intensity. These issues require a robust determination of the relevant masses (BH, stars and gas), which is difficult in the case of distant high-redshift galaxies that are unresolved. In this paper, we seek to identify spectral diagnostics that may tell us about the relative masses of the BH, the gas mass and stellar mass. We consider general features of SEDs of galaxies that harbour growing massive BHs, forming stars and interstellar/circumgalactic gas. We focus on observational manifestations of possible predominances or intermittent variations in evolutionary episodes of growing massive BHs and forming stellar populations. We consider simplified scenarios for star formation and massive BHs growth, and simple models for chemical composition of gas, for dust free gas as well as for gas with dust mass fraction of $1/3$ of the metal content. We argue that wideband multi-frequency observations (X-ray to submillimeter) of the composite emission spectra of growing BH, stellar population and nebular emission of interstellar gas are sufficient to infer their masses.

[40]  arXiv:2003.14040 [pdf, other]

Title: gSeaGen: the KM3NeT GENIE-based code for neutrino telescopes

Authors: Sebastiano Aiello, Arnauld Albert, Sergio Alves Garre, Zineb Aly, Fabrizio Ameli, Michel Andre, Giorgos Androulakis, Marco Anghinolfi, Mancia Anguita, Gisela Anton, Miquel Ardid, Julien Aublin, Christos Bagatelas, Giancarlo Barbarino, Bruny Baret, Suzan Basegmez du Pree, Meriem Bendahman, Edward Berbee, Vincent Bertin, Simone Biagi, Andrea Biagioni, Matthias Bissinger, Markus Boettcher, Jihad Boumaaza, Simon Bourret, Mohammed Bouta, Mieke Bouwhuis, Cristiano Bozza, Horea Branzas, Marc Bruchner, Ronald Bruijn, Jürgen Brunner, Ernst-Jan Buis, Raffaele Buompane, Jose Busto, David Calvo, Antonio Capone, Víctor Carretero, Paolo Castaldi, Silvia Celli, Mohamed Chabab, Nhan Chau, Andrew Chen, Silvio Cherubini, Vitaliano Chiarella, Tommaso Chiarusi, Marco Circella, Rosanna Cocimano, Joao Coelho, et al. (187 additional authors not shown)

Comments: 45 pages, 10 figures

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

The gSeaGen code is a GENIE-based application developed to efficiently generate high statistics samples of events, induced by neutrino interactions, detectable in a neutrino telescope. The gSeaGen code is able to generate events induced by all neutrino flavours, considering topological differences between track-type and shower-like events. Neutrino interactions are simulated taking into account the density and the composition of the media surrounding the detector. The main features of gSeaGen are presented together with some examples of its application within the KM3NeT project.

[41]  arXiv:2003.14044 [pdf, ps, other]

Title: Thermally Driven Angular Momentum Transport in Hot Jupiters

Authors: Cong Yu (Sun Yat-sen University)

Comments: 6 pages, 3 figures, ApJ Letter Accepted

Journal-ref: ApJ Letter 2020

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

We study the angular momentum transport inside the hot Jupiters under the the influences of gravitational and thermal forcing. Due to the strong stellar irradiation, radiative region develops on top of the convective region. Internal gravity waves are launched at the radiative-convective boundaries (RCBs). The thermal response is dynamical and plays an important role in the angular momentum transport. By separating the gravitational and thermal forcing terms, we identify the thermal effects for increasing the angular momentum transport. For the low frequency (in the co-rotating frame with planets) prograde (retrograde) tidal frequency, the angular momentum flux is positive (negative). The tidal interactions tends to drive the planet to the synchronous state. We find that the angular momentum transport associated with the internal gravity wave is very sensitive to relative position between the RCB and the penetration depth of the thermal forcing. If the RCB is in the vicinity of the thermal forcing penetration depth, even with small amplitude thermal forcing, the thermally driven angular momentum flux could be much larger than the flux induced by gravitational forcing. The thermally enhanced torque could drive the planet to the synchronous state in as short as a few $10^4$ years.

[42]  arXiv:2003.14064 [pdf, other]

Title: Physical Characterisation of Interstellar Comet 2I/2019 Q4 (Borisov)

Authors: Man-To Hui, Quan-Zhi Ye, Dora Föhring, Denise Hung, David J. Tholen

Comments: AJ, under review

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

We present a study of interstellar comet 2I/2019 Q4 (Borisov) using both preperihelion and postperihelion observations spanning late September 2019 through late January 2020. The intrinsic brightness of the comet was observed to continuously decline throughout the timespan, not due to the phase effect but the decreasing effective scattering cross-section as a result of volatile sublimation with a slope of $-0.43 \pm 0.02$ km$^{2}$ d$^{-1}$. Given the measurement uncertainties, we witnessed no change in the slightly reddish colour of the comet, with mean values of $\left \langle g - r \right \rangle = 0.68 \pm 0.04$, $\left \langle r - i \right \rangle = 0.23 \pm 0.03$, and the normalised reflectivity gradient across the $g$ and $i$ bands $\overline{S'} \left(g,i\right) = \left(10.6 \pm 1.4\right)$ % per $10^3$ \AA, all unremarkable in the context of solar system comets. Using the available astrometric observations, we have a statistically confident detection of the nongravitational acceleration of the comet, implying that the nucleus is most likely $\lesssim$0.4 km in radius, and that a fraction of $\gtrsim$0.4% of the total nucleus in mass has been eroded due to the sublimation activity since the earliest observation of the comet in 2018 December by the time of perihelion. Our morphology simulation suggests that the dust ejection speed increased from $\sim$4 m s$^{-1}$ in 2019 September to $\sim$7 m s$^{-1}$ around perihelion for the optically dominant dust grains of $\beta \sim 0.01$, and that the observable dust grains are no smaller than micron size.

[43]  arXiv:2003.14066 [pdf, other]

Title: Generic 3-point Statistics with Tensor Modes in Light of Swampland and TCC

Authors: Abhishek Naskar, Supratik Pal

Comments: 20 pages, 1 figure

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

Recently proposed Swampland Criteria (SC) and Trans-Planckian Censorship Conjecture (TCC) together put stringent theoretical constraints on slow roll inflation, raising a question on future prospects of detection of Primordial Gravitational Waves (PGW). As it appears, the only option to relax the constraints is by considering Non Bunch Davies (NBD) initial states, that in turn brings back the observational relevance of PGW via its 2-point function. In this article we develop consistent 3-point statistics with tensor modes for all possible correlators (auto and mixed) for NBD initial states in the light of SC and TCC in a generic, model independent framework of Effective Field Theory of inflation. We also construct the templates of the corresponding nonlinearity parameters $f_{NL}$ for different shapes of relevance and investigate if any of the 3-point correlators could be of interest for future CMB missions. Our analysis reveals that the prospects of detecting the tensor auto correlator are almost nil whereas the mixed correlators might be relevant for future CMB missions.

[44]  arXiv:2003.14079 [pdf, ps, other]

Title: Site-testing at Muztagh-ata site I: Ground Meteorology and Sky Brightness

Authors: Jing Xu, Ali Esamdin, Jin-xin Hao, Jin-min Bai, Ji Yang, Xu Zhou, Yong-qiang Yao, Jin-liang Hou, Guang-xin Pu, Guo-jie Feng, Chun-hai Bai, Peng Wei, Shu-guo Ma, Abudusaimaitijiang Yisikandee, Le-tian Wang, Xuan Zhang, Liang Ming, Lu Ma, Jin-zhong Liu, Zi-huang Cao, Yong-heng Zhao, Lu Feng, Jian-rong Shi, Hua-lin Chen, Chong Pei, Xiao-jun Jiang, Jian-feng Wang, Jian-feng Tian, Yan-jie Xue, Jing-yao Hu, Yun-ying Jiang

Comments: 16 pages, 19 figures

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

Site-testing is crucial for achieving the goal of scientific research and analysis of meteorological and optical observing conditions is one of the basic tasks of it. As one of three potential sites to host 12-meter Large Optical/infrared Telescope (LOT), Muztagh-ata site which is located on the Pamirs Plateau in west China's Xinjiang began its site-testing task in the spring of 2017. In this paper, we firstly start with an introduction to the site and then present a statistical analysis of the ground-level meteorological properties such as air temperature, barometric pressure, relative humidity, wind speed and direction, recorded by automatic weather station with standard meteorological sensors for two-year long. We also show the monitoring results of sky brightness during this period.

[45]  arXiv:2003.14096 [pdf, other]

Title: Eccentric grazing envelope evolution towards type IIb supernova progenitors

Authors: Dmitry Shishkin, Noam Soker (Technion, Israel)

Comments: To be submitted in two days to allow comments by readers

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

We simulate the evolution of eccentric binary systems in the frame of the grazing envelope evolution (GEE) channel for the formation of Type IIb supernovae (SNe IIb), and find that extra mass removal by jets increases the parameter space for the formation of SNe IIb in this channel. To explore the role of eccentricity and the extra mass removal by jets in the GEE we use the stellar evolutionary code MESA~binary. The initial primary and secondary masses are M1i=15Mo and M2i=2.5Mo, respectively. We examine initial semi-major axes of 600-1000Ro, and eccentricities in the range of e=0-0.9. Both Roche lobe overflow (RLOF) and mass removal by jets, followed by a wind from the SN IIb progenitor, leave a hydrogen mass in the exploding star of M(H,f)=0.05Mo. This is compatible with a SN IIb progenitor. We find that in many cases, with and without the extra mass removal by jets, the system can enter a common envelope evolution (CEE) phase, and then gets out from it. Despite the large uncertainties, extra mass removal by jets substantially increases the likelihood of the system to get out from a CEE. This strengthens earlier conclusions for circular orbits. In some cases RLOF alone, without mass removal by jets, can form SN IIb progenitors. We estimate that the extra mass removal by jets in the GEE channel increases the number of progenitors relative to that by RLOF alone by about a factor of two.

[46]  arXiv:2003.14097 [pdf, other]

Title: Shock breakouts from red supergiants: analytical and numerical predictions

Authors: Alexandra Kozyreva, Ehud Nakar, Roni Waldman, Sergei Blinnikov, Petr Baklanov

Comments: 12 figures, 2 tables. Accepted for publication in MNRAS

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

Shock breakout (SBO) signal is the first signature of the supernova explosion apart from gravitational waves and neutrinos. Observational properties of SBO, such as bolometric luminosity and colour temperature, connect to the supernova progenitor and explosion parameters. Detecting SBO or SBO-cooling will constrain the progenitor and explosion models of collapsing stars. In the light of recently launched eROSITA telescope, the rate for detection of SBO is a few events during a year. In the current study, we examine the analytic formulae derived by Shussman et al. (2016). We use four red supergiant models from their study, while running explosions with the radiation hydrodynamics code STELLA. We conclude that there is a good agreement between analytic and numerical approaches for bolometric luminosity and colour temperature during SBO. The analytic formulae for the SBO signal based on the global supernova parameters can be used instead of running time-consuming numerical simulations. We define spectral range where analytic formulae for the SBO spectra are valid. We provide improved analytical expression for the SBO spectral energy distribution. We confirm dependence of colour temperature on radius derived by analytical studies and suggest to use early time observations to confine the progenitor radius. Additionally we show the prediction for the SBO signal from red supergiants as seen by eROSITA instrument.

[47]  arXiv:2003.14129 [pdf, other]

Title: Sensitivity of gas-grain chemical models to surface reaction barriers: Effect from a key carbon-insertion reaction, C + H$_2$ $\rightarrow$ CH$_2$

Authors: Matjaž Simončič, Dmitry Semenov, Serge Krasnokutski, Thomas Henning, Cornelia Jäger

Comments: Submitted to Astronomy & Astrophysics (A&A), 9 pages

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

The feasibility of contemporary gas-grain astrochemical models depends on the availability of accurate kinetics data, in particular, for surface processes. We study the sensitivity of gas-grain chemical models to the energy barrier Ea of the important surface reaction between some of the most abundant species: C and H2 (surface C + surface H2 = surface CH2). We used the gas-grain code ALCHEMIC to model the time-dependent chemical evolution over a 2D grid of densities (nH: 10^{3} - 10^{12}cm^{-3}) and temperatures (T: 10 - 300 K), assuming UV-dark (Av = 20 mag) and partly UV-irradiated (Av = 3 mag) conditions that are typical of the dense interstellar medium. We considered two values for the energy barrier of the surface reaction, Ea = 2500 K (as originally implemented in the networks) and Ea = 0 K (as measured in the laboratory and computed by quantum chemistry simulations). We find that if the C + H2 = CH2 surface reaction is barrierless, a more rapid conversion of the surface carbon atoms into methane ice occurs. Overproduction of the CHn hydrocarbon ices affects the surface formation of more complex hydrocarbons, cyanides and nitriles, and CS-bearing species at low temperatures < 10-15 K. The surface hydrogenation of CO and hence the synthesis of complex (organic) molecules become affected as well. As a result, important species whose abundances may change by more than a factor of two at 1 Myr include atomic carbon, small mono-carbonic (C1) and di-carbonic (C2) hydrocarbons, CO2, CN, HCN, HNC, HNCO, CS, H2CO, H2CS, CH2CO, and CH3OH (in either gas and/or ice). The abundances of key species, CO, H2O, and N2 as well as O, HCO+, N2H+, NH3, NO, and most of the S-bearing molecules, remain almost unaffected. Further accurate laboratory measurements and quantum chemical calculations of the surface reaction barriers will be crucial to improve the accuracy of astrochemical models.

[48]  arXiv:2003.14131 [pdf, other]

Title: Enceladus Farm: Can plants grow with Enceladus' water? (Preliminary Report)

Authors: Daigo Shoji

Comments: 12 pages, 7 figures, Preliminary results. Comments are welcome

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

Enceladus is a saturnian satellite that should have liquid water inside of it (subsurface ocean). Measurements and experiments on water plume from Enceladus have revealed that Enceladus' ocean contains several salts such as NaCl. On the Earth, salt in soil has become a serious problem for agriculture, and importance of salt-tolerant plants are indicated. In order to test the effect of Enceladus' water to terrestrial plant, by hydroponic, we tried to grow three salt-tolerant plants (ice plant, swiss chard and salicornia) simulating Enceladus' water (Enceladus Farm project). Using water with 0.33% NaCl and 0.4% NaHCO$_3$, which is consistent with the observations of Enceladus, all plants could grow if they were germinated and grown with pure water until each plant had a few leaves. However, growth rate can be suppressed compared with the plants cultivated with pure water. Because our first test was performed with loose conditions, more works are needed to evaluate the effect of Enceladus' water to plant growth. However, in addition to the works to grow plants on lunar and martian grounds, Enceladus' water may be used to consider properties of plant from wider environment.

[49]  arXiv:2003.14144 [pdf, other]

Title: Long period Ap stars discovered with TESS data

Authors: Gautier Mathys, Donald W. Kurtz, Daniel L. Holdsworth

Comments: Submitted to A&A; 18 pages, 11 figures

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

The TESS space mission is producing superb data for asteroseismology, eclipsing binary stars, gyrochronology, and other fields of stellar astronomy where the data are variable light curves. We show that TESS data are excellent for astrophysical inference from peculiar stars that show variability. The Ap stars have the strongest magnetic fields of any main-sequence stars. Some have been shown to have rotation periods of months to centuries. The astrophysical cause of their slow rotation -- the braking mechanism -- is not known with certainty. These stars are rare: there are currently about 3 dozen with known periods. The magnetic Ap stars have long-lived spots that allow precise determination of their rotation periods. We show that most Ap stars with TESS data that show no low-frequency variability must have rotation periods longer than a TESS sector of 27 d. We find 60 Ap stars in the southern ecliptic hemisphere TESS data with no rotational variability, of which at most a few can be pole-on, and six likely have nearly aligned magnetic and rotation axes. Of the other 54, 31 were previously known to have long rotation periods or low projected equatorial velocities, which proves our technique; 23 are new discoveries. These are prime targets for long-term magnetic studies. We also find that 22 per cent of long-period Ap stars are roAp stars, versus only 4 per cent of the Ap stars studied with TESS sector 1 and 2 data. This work demonstrates astrophysical inference from nonvariable stars -- "something for nothing".

[50]  arXiv:2003.14178 [pdf, ps, other]

Title: Hemispheric handedness in the Galactic synchrotron polarization foreground

Authors: Axel Brandenburg, Marcus Brüggen

Comments: 7 pages, 4 figures, submitted to ApJL

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

Large-scale magnetic fields in the Milky Way are thought to be created by an $\alpha\Omega$ dynamo, which implies that they should have opposite handedness North and South of the midplane of the Galactic disk. Here we attempt to detect this variation in handedness using polarization data from the Wilkinson Microwave Anisotropy Probe. Previous analyses of the parity-even and parity-odd constituents of linear polarization of the global dust and synchrotron emission have focused on quadratic correlations in spectral space of, and between, these two components. Here, by contrast, we analyze the parity-odd polarization of the magnetic field itself and show that it has opposite signs in Northern and Southern Galactic hemispheres. This is suggestive of the presence of magnetic helicity in the Galaxy and thereby an important diagnostic for Galactic dynamo models. Comparison with a Galactic mean-field dynamo model shows broad qualitative agreement. The observed hemispheric dependence for the azimuthally averaged parity-odd polarization is recovered if, in the model, the observer is placed sufficiently far away from the Galactic center.

[51]  arXiv:2003.14186 [pdf, other]

Title: A Survey of Computational Tools in Solar Physics

Authors: Monica G. Bobra, Stuart J. Mumford, Russell J. Hewett, Steven D. Christe, Kevin Reardon, Sabrina Savage, Jack Ireland, Tiago M. D. Pereira, Bin Chen, David Pérez-Suárez

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Physics Education (physics.ed-ph)

The SunPy Project developed a 13-question survey to understand the software and hardware usage of the solar physics community. 364 members of the solar physics community, across 35 countries, responded to our survey. We found that 99$\pm$0.5% of respondents use software in their research and 66% use the Python scientific software stack. Students are twice as likely as faculty, staff scientists, and researchers to use Python rather than Interactive Data Language (IDL). In this respect, the astrophysics and solar physics communities differ widely: 78% of solar physics faculty, staff scientists, and researchers in our sample uses IDL, compared with 44% of astrophysics faculty and scientists sampled by Momcheva and Tollerud (2015). 63$\pm$4% of respondents have not taken any computer-science courses at an undergraduate or graduate level. We also found that most respondents utilize consumer hardware to run software for solar-physics research. Although 82% of respondents work with data from space-based or ground-based missions, some of which (e.g. the Solar Dynamics Observatory and Daniel K. Inouye Solar Telescope) produce terabytes of data a day, 14% use a regional or national cluster, 5% use a commercial cloud provider, and 29% use exclusively a laptop or desktop. Finally, we found that 73$\pm$4% of respondents cite scientific software in their research, although only 42$\pm$3% do so routinely.

[52]  arXiv:2003.14198 [pdf, ps, other]

Title: Analytical solution of the Colombo top problem

Authors: J. Haponiak, S. Breiter, D. Vokrouhlicky

Comments: to be published in Celestial Mechanics and Dynamical Astronomy

Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Mathematical Physics (math-ph)

The Colombo top is a basic model in the rotation dynamics of a celestial body moving on a precessing orbit and perturbed by a gravitational torque. The paper presents a detailed study of analytical solution to this problem. By solving algebraic equations of degree 4, we provide the expressions for the extreme points of trajectories as functions of their energy. The location of stationary points (known as the Cassini states) is found as the function of the two parameters of the problem. Analytical solution in terms the Weierstrass and the Jacobi elliptic functions is given for regular trajectories. Some trajectories are expressible through elementary functions: not only the homoclinic orbits, as expected, but also a special periodic solution whose energy is equal to that of the first Cassini state (unnoticed in previous studies).

[53]  arXiv:2003.14209 [pdf, other]

Title: The dynamics of the γ Vel cluster and nearby Vela OB2 association

Authors: Joseph J. Armstrong, Nicholas J. Wright, R. D. Jeffries, R. J. Jackson

Comments: 9 pages, 8 figures, 1 table, accepted for publication in MNRAS

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

The kinematics of low-mass stars in nearby OB associations can provide clues about their origins and evolution. Combining the precise positions, proper motions and parallaxes given in the second Gaia Data Release with radial velocity measurements obtained with the Hermes spectrograph at the Anglo-Australian Telescope, we have an opportunity to study in detail the kinematics of low-mass stars belonging to the nearby $\gamma$ Vel cluster and the Vela OB2 association it is projected against. The presence of lithium is used to confirm the youth of our targets. We separate our sample into the cluster and association populations based on the membership probabilities of Jeffries et al. 2014, their parallaxes, and kinematics. We find strong evidence for expansion in the OB association population with at least 4$\sigma$ significance along all three axes, though the expansion is notably anisotropic. We discuss these results in the context of cluster and association dispersal theories.

[54]  arXiv:2003.14220 [pdf, other]

Title: Discrimination of Dark Matter Mass and Velocity Distribution by Directional Detection

Authors: Keiko I. Nagao

Comments: prepared for proceedings of NDM 2020, 6pages, 10 figures

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

Velocity distribution of dark matter is assumed to be isotropic in most cases, however, anisotropy is suggested in some simulations. Directional direct detection of dark matter is a hopeful way to discriminate the anisotropy of dark matter velocity distribution. We simulate the dark matter and target scattering in the directional direct detection, and investigate conditions required to discriminate the anisotropy. If dark matter mass is known, $O(10^3)-O(10^4)$ events are required for the discrimination if the dark matter mass is known by other experiments. We also study the case that the dark matter mass is not known, and in analysis using both the recoil energy and the scattering angle data, both the dark matter mass and the anisotropy can be restricted much better than the analysis only with either of them.

[55]  arXiv:2003.14222 [pdf, other]

Title: The physics of Galaxy Evolution with SPICA observations

Authors: Luigi Spinoglio, Juan A. Fernandez-Ontiveros, Sabrina Mordini

Comments: Contributed talk at the IAU Symp 359 Galaxy Evolution and Feedback Across Different Environments, 2020 March 2-6, Bento Concalves, Brazil. arXiv admin note: text overlap with arXiv:1911.12181

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

The evolution of galaxies at Cosmic Noon (redshift 1<z<3) passed through a dust-obscured phase, during which most stars formed and black holes in galactic nuclei started to shine, which cannot be seen in the optical and UV, but it needs rest frame mid-to-far IR spectroscopy to be unveiled. At these frequencies, dust extinction is minimal and a variety of atomic and molecular transitions, tracing most astrophysical domains, occur. The future IR space telescope mission, SPICA, currently under evaluation for the 5th Medium Size ESA Cosmic Vision Mission, fully redesigned with its 2.5 m mirror cooled down to T < 8K will perform such observations. SPICA will provide for the first time a 3-dimensional spectroscopic view of the hidden side of star formation and black hole accretion in all environments, from voids to cluster cores over 90% of cosmic time. Here we outline what SPICA will do in galaxy evolution studies.

[56]  arXiv:2003.14262 [pdf, other]

Title: Comparison of Latitude Distribution and Evolution of Even and Odd Sunspot Cycles

Authors: Jouni J. Takalo

Comments: 11 pages, 5 figures

Journal-ref: Sol Phys 295, 49 (2020)

Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Applications (stat.AP)

We study the latitudinal distribution and evolution of sunspot areas from Solar Cycle 12 to Solar Cycle 23 (SC12-SC23) and sunspot-groups of from Solar Cycle 8 to Solar Cycle 23 (SC8-SC23) for even and odd cycles. The Rician distribution is the best-fit function for both even and odd sunspots group latitudinal occurrence. The mean and variance for even northern/southern butterfly wing sunspots are 14.94/14.76 and 58.62/56.08, respectively, and the mean and variance for odd northern/southern wing sunspots are 15.52/15.58 and 61.77/58.00, respectively. Sunspot groups of even cycle wings are thus at somewhat lower latitudes on the average than sunspot groups of the odd cycle wings, i.e., about 0.6 degrees for northern hemisphere wings and 0.8 degrees for southern hemisphere wings. The spatial analysis of sunspot areas between SC12-SC23 shows that the small sunspots are at lower solar latitudes of the sun than the large sunspots for both odd and even cycles, and also for both hemispheres. Temporal evolution of sunspot areas shows a lack of large sunspots after four years (exactly between 4.2-4.5 years), i.e., about 40\% after the start of the cycle, especially for even cycles. This is related to the Gnevyshev gap and is occurring at the time when the evolution of the average sunspot latitudes cross about 15 degrees. The gap is, however, clearer for even cycles than odd ones. Gnevyshev gap divides the cycle into two disparate parts: the ascending phase/cycle maximum and the declining phase of the sunspot cycle.

[57]  arXiv:2003.14272 [pdf, other]

Title: Initial results from a realtime FRB search with the GBT

Authors: Devansh Agarwal, D.R. Lorimer, M.P. Surnis, X. Pei, A. Karastergiou, G. Golpayegani, D. Werthimer, J. Cobb, M.A. McLaughlin, S. White, W. Armour, D.H.E. MacMahon, A.P.V. Siemion, G. Foster

Comments: 9 pages, 7 figures, submitted to MNRAS

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

We present the data analysis pipeline, commissioning observations and initial results from the GREENBURST fast radio burst (FRB) detection system on the Robert C. Byrd Green Bank Telescope (GBT) previously described by Surnis et al. which uses the 21~cm receiver observing commensally with other projects. The pipeline makes use of a state-of-the-art deep learning classifier to winnow down the very large number of false positive single-pulse candidates that mostly result from radio frequency interference. In our observations totalling 156.5 days so far, we have detected individual pulses from 20 known radio pulsars which provide an excellent verification of the system performance. We also demonstrate, through blind injection analyses, that our pipeline is complete down to a signal-to-noise threshold of 12. Depending on the observing mode, this translates to peak flux sensitivities in the range 0.14--0.89~Jy. Although no FRBs have been detected to date, we have used our results to update the analysis of Lawrence et al. to constrain the FRB all-sky rate to be $1140^{+200}_{-180}$ per day above a peak flux density of 1~Jy. We also constrain the source count index $\alpha=0.83\pm0.06$ which indicates that the source count distribution is substantially flatter than expected from a Euclidean distribution of standard candles (where $\alpha=1.5$). We discuss this result in the context of the FRB redshift and luminosity distributions. Finally, we make predictions for detection rates with GREENBURST, as well as other ongoing and planned FRB experiments.

[58]  arXiv:2003.14311 [pdf, other]

Title: Outstanding Challenges of Exoplanet Atmospheric Retrievals

Authors: Joanna K. Barstow, Kevin Heng

Comments: 30 pages, 6 figures. Accepted by Space Science Reviews

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

Spectral retrieval has long been a powerful tool for interpreting planetary remote sensing observations. Flexible, parameterised, agnostic models are coupled with inversion algorithms in order to infer atmospheric properties directly from observations, with minimal reliance on physical assumptions. This approach, originally developed for application to Earth satellite data and subsequently observations of other Solar System planets, has been recently and successfully applied to transit, eclipse and phase curve spectra of transiting exoplanets. In this review, we present the current state-of-the-art in terms of our ability to accurately retrieve information about atmospheric chemistry, temperature, clouds and spatial variability; we discuss the limitations of this, both in the available data and modelling strategies used; and we recommend approaches for future improvement.

[59]  arXiv:2003.14314 [pdf, other]

Title: NGTS J214358.5-380102 -- NGTS discovery of the most eccentric known M-Dwarf binary system

Authors: Jack S. Acton, Michael R. Goad, Liam Raynard, Sarah L. Casewell, James A.G. Jackman, Richard D. Alexander, David R. Anderson, Daniel Bayliss, Edward M. Bryant, Matthew R. Burleigh, Claudia Belardi, Benjamin F. Cooke, Phillip Eigmüller, Samuel Gill, James S. Jenkins, Monika Lendl, Tom Louden, James McCormac, Maximiliano Moyano, Louise D. Nielsen, Rosanna H. Tilbrook, Stéphane Udry, Christopher A. Watson, Richard G. West, Peter J. Wheatley, Jose I. Vines

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

We present the discovery of NGTS J214358.5-380102, an eccentric M-dwarf binary discovered by the Next Generation Transit Survey. The system period of 7.618 days is greater than many known eclipsing M-dwarf binary systems. Its orbital eccentricity of $0.323^{+0.0014}_{-0.0037}$, is large relative to the period and semi-major axis of the binary. Global modelling of photometry and radial velocities indicate stellar masses of $M_A$=$0.426 ^{+0.0056}_{-0.0049}$, $M_B$=$0.455 ^{+0.0058}_{-0.0052}$ and stellar radii $R_A$=$0.461 ^{+0.038}_{-0.025}$ $R_B$=$0.411 ^{+0.027}_{-0.039}$, respectively. Comparisons with stellar models for low mass stars show that one star is consistent with model predictions whereas the other is substantially oversized. Spectral analysis of the system suggests a primary of spectral type M3V, consistent with both modelled masses and radii, and with SED fitting of NGTS photometry. As the most eccentric M-dwarf binary known, \Nstarlong provides an interesting insight into the strength of tidal effects in the circularisation of stellar orbits.

[60]  arXiv:2003.14327 [pdf, other]

Title: A PDF PSA, or Never gonna set_xscale again -- guilty feats with logarithms

Authors: John C. Forbes

Comments: To be submitted to the Astro-pedantic Journal on April 1, 2020

Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Instrumentation and Methods for Astrophysics (astro-ph.IM)

In the course of doing astronomy, one often encounters plots of densities, for example probability densities, flux densities, and mass functions. Quite frequently the ordinate of these diagrams is plotted logarithmically to accommodate a large dynamic range. In this situation, I argue that it is critical to adjust the density appropriately, rather than simply setting the x-scale to `log' in your favorite plotting code. I will demonstrate the basic issue with a pedagogical example, then mention a few common plots where this may arise, and finally some possible exceptions to the rule.

[61]  arXiv:2003.14336 [pdf, other]

Title: HD 196390: A tight correlation of differential abundances with condensation temperature

Authors: Charles R. Cowley, Donald J. Bord, Kutluay Yüce

Comments: An updated and expanded version of a paper accepted by Research Notes of the AAS

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

Bedell et al. (2018) give precision differential abundances for 79 mostly G-dwarf stars. We correct these abundances for Galactic chemical evolution in a manner similar to that used by these authors but with parameters derived from linear fits to plots of [El/H] vs. age in lieu of [El/Fe]. We examine the resulting abundances for correlations with the 50% condensation temperature using values from both Lodders (2003) and Wood et al. (2019), and compare with the results of Bedell et al. HD 196390 is distinct in having the most significant correlation of the 79-star sample. We report statistics for a subset of stars with lower significance, but of some interest.

[62]  arXiv:2003.14340 [pdf, other]

Title: Observing the earliest moments of supernovae using strong gravitational lenses

Authors: Max Foxley-Marrable, Thomas E. Collett, Chris Frohmaier, Daniel A. Goldstein, Daniel Kasen, Elizabeth Swann, David Bacon

Comments: 17 pages, 15 figures (including appendices). Submitted to MNRAS

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

We determine the viability of exploiting lensing time delays to observe strongly gravitationally lensed supernovae (gLSNe) from the moment of explosion. Assuming a plausible discovery strategy, the Legacy Survey of Space and Time (LSST) and the Zwicky Transient Facility (ZTF) will discover $\sim$ 110 and $\sim$ 1 systems per year before the supernova (SN) explosion in the final image respectively. Systems will be identified 11.7$^{+29.8}_{-9.3}$ days before the final explosion. We then explore the possibility of constraining progenitor models with early phase observations for Type IIP and Type Ia SNe in LSST discovered systems. Using a simulated Type IIP explosion, we predict that the shock breakout in one trailing image per year will peak at $\lesssim$ 24.1 mag ($\lesssim$ 23.3) in the $B$-band ($F218W$), however evolving over a timescale of $\sim$ 30 minutes. Using an analytic model of Type Ia companion interaction, we find that in the $B$-band we should observe at least one shock cooling emission event per year that peaks at $\lesssim$ 26.3 mag ($\lesssim$ 29.6) assuming all Type Ia gLSNe have a 1 M$_\odot$ red giant (main sequence) companion. We perform Bayesian analysis to investigate how well deep observations with 1 hour exposures on the European Extremely Large Telescope would discriminate between Type Ia progenitor populations. We find that if all Type Ia SNe evolved from the double-degenerate channel, then observations of the lack of early blue flux in 10 (50) trailing images would rule out more than 27% (19%) of the population having 1 M$_\odot$ main sequence companions at 95% confidence.

[63]  arXiv:2003.14345 [pdf, other]

Title: Searching for Space Vampires with TEvSS

Authors: Maximilian N. Günther, David A. Berardo

Comments: 3 pages, 2 figures, 0 tables, submitted to Journal of Space Vampire Research

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

It is a truth universally acknowledged, that a single human in possession of a good space telescope, must be in search of a space vampire. Here, we showcase our search for transit signatures of tidally locked space vampires, trapped in the gravitational pull of late M-dwarfs. We generate forward models representing two potential space vampire populations - those in bat shape and those in humanoid shape. We search lightcurves from the Transiting Exo-Vampire Survey Satellite (TEvSS) using a template matching algorithm and fit them using our allesfitter software. Adding the information gained from TEvSS data, we greatly decrease the uncertainty for the existence and occurrence rates of space vampires, and constrain eta(space vampire) to a range of 0% to 100% (or more). These precise analyses will be crucial for optimizing future observing schedules for space-vampire characterization with the James Webb Space-Vampire Telescope (JWSvT) and the Extremely-Large-Vampire Telescopes (ELvTs).

[64]  arXiv:2003.14347 [pdf, other]

Title: Discovery of a retrogradely rotating neutron star in the X-ray pulsar GX 301$-$2

Authors: Juhani Mönkkönen, Victor Doroshenko, Sergey S. Tsygankov, Armin Nabizadeh, Pavel Abolmasov, Juri Poutanen

Comments: 5 pages, 2 figures, accepted by MNRAS

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

We report on the analysis of the spin evolution of a slow X-ray pulsar GX 301$-$2 along the orbit using long-term monitoring by Fermi/GBM. Based on the observationally confirmed accretion scenario and an analytical model for the accretion of angular momentum we demonstrate that in this system, the neutron star spins retrogradely, that is, in a direction opposite to the orbital motion. This first-of-a-kind discovery of such a system proves the principal possibility of retrograde rotation in accreting systems with suitable accretion torque, and might have profound consequences for our understanding of the spin evolution of X-ray pulsars, estimates of their initial spin periods, and the ultimate result of their evolution.

[65]  arXiv:2003.14351 [pdf, other]

Title: Twinlike models for parametrized dark energy

Authors: J.D. Dantas, J.J. Rodrigues

Comments: 6 pages, 4 figures; submitted to EPJC

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

We study cosmological models involving a single real scalar field that has an equation of state parameter which evolves with cosmic time. We highlight some common parametrizations for the equation of state as a function of redshift in the context of twinlike theories. The procedure is used to introduce different models that have the same acceleration parameter, with the very same energy densities and pressure in flat spacetime.

[66]  arXiv:2003.14371 [pdf, other]

Title: Allesfitter: Flexible Star and Exoplanet Inference From Photometry and Radial Velocity

Authors: Maximilian N. Günther, Tansu Daylan

Comments: 27 pages, 11 figures, 5 tables, will be submitted to AAS journals

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

We present allesfitter, a public and open-source python software for flexible and robust inference of stars and exoplanets given photometric and radial velocity data. Allesfitter offers a rich selection of orbital and transit/eclipse models, accommodating multiple exoplanets, multi-star systems, transit-timing variations, phase curves, stellar variability, star spots, stellar flares, and various systematic noise models including Gaussian Processes. It features both parameter estimation and Bayesian model selection, allowing to easily run either a Markov Chain Monte Carlo (MCMC) or Nested Sampling fit. For novice users, a graphical user interface allows to specify all input and perform analyses; for python users, all modules can be readily imported in any existing scripts. Allesfitter also produces publication-ready tables, LaTeX commands, and figures. The software is publicly available (https://github.com/MNGuenther/allesfitter), pip-installable (pip install allesfitter) and well documented (www.allesfitter.com).

[67]  arXiv:2003.14406 [pdf, other]

Title: Physical Properties of 299 NEOs Manually Recovered in Over Five Years of NEOWISE Survey Data

Authors: Joseph R. Masiero, Patrice Smith, Lean D. Teodoro, A.K. Mainzer, R.M. Cutri, T. Grav, E. L. Wright

Comments: Accepted for publication to the AAS Planetary Science Journal

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

Thermal infrared measurements of near-Earth objects provide critical data for constraining their physical properties such as size. The NEOWISE mission has been conducting an all-sky infrared survey to gather such data and improve our understanding of this population. While automated routines are employed to identify the majority of moving objects detected by NEOWISE, a subset of objects will have dynamical properties that fall outside the window detectable to these routines. Using the population of known near-Earth objects, we have conducted a manual search for detections of these objects that were previously unreported. We report 303 new epochs of observations for 299 unique near-Earth objects of which 239 have no previous physical property characterization from the NEOWISE Reactivation mission. As these objects are drawn from a list with inherent optical selection biases, the distribution of measured albedos is skewed to higher values than is seen for the diameter-selected population detected by the automated routines. These results demonstrate the importance and benefit of periodic searches of the archival NEOWISE data.

[68]  arXiv:2003.14410 [pdf, other]

Title: Superflares and Variability in Solar-Type Stars with $\it TESS$ in the Southern Hemisphere

Authors: Lauren Doyle, Gavin Ramsay, J. Gerard Doyle

Comments: Accepted for publication in MNRAS. 16 pages, 11 figures and one online table available in the published version

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

Superflares on solar-type stars has been a rapidly developing field ever since the launch of $\it Kepler$. Over the years, there have been several studies investigating the statistics of these explosive events. In this study, we present a statistical analysis of stellar flares on solar-type stars made using photometric data in 2-min cadence from $\it TESS$ of the whole southern hemisphere (sectors 1 - 13). We derive rotational periods for all stars in our sample from rotational modulations present in the lightcurve as a result of large starspot(s) on the surface. We identify 1980 stellar flares from 209 solar-type stars with energies in the range of $10^{31} - 10^{36}$erg (using the solar flare classification, this corresponds to X1 - X100,000) and conduct an analysis into their properties. We investigate the rotational phase of the flares and find no preference for any phase suggesting the flares are randomly distributed. As a benchmark, we use GOES data of solar flares to detail the close relationship between solar flares and sunspots. In addition, we also calculate approximate spot areas for each of our stars and compare this to flare number, rotational phase, and flare energy. Additionally, two of our stars were observed in the continuous viewing zone with lightcurves spanning one year, as a result, we examine the stellar variability of these stars in more detail.

Cross-lists for Wed, 1 Apr 20

[69]  arXiv:1908.09732 (cross-list from hep-ph) [pdf, other]

Title: Vector gauge boson radiation from compact binary systems in a gauged $L_μ-L_τ$ scenario

Authors: Tanmay Kumar Poddar, Subhendra Mohanty, Soumya Jana

Comments: 15 pages, 2 figures, Journal version , to appear in Phys ReV D

Journal-ref: Phys. Rev. D 100, 123023 (2019)

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

The orbital period of a compact binary system decays mainly due to quadrupole gravitational radiation, which agrees with the observation to within one percent. Other types of radiation such as ultralight scalar or pseudoscalar radiation, massive vector boson radiation also contribute to the decay of orbital period as long as the mass of the emitted particle is less than the orbital frequency of the compact binary system. We obtain an expression of the energy loss due to the radiation of massive vector field from the neutron star-neutron star and neutron star-white dwarf binaries. Due to large chemical potential of the degenerate electrons, neutron stars have large muon charge. We derive the energy loss due to $U(1)_{L_\mu-L_\tau}$ gauge boson radiation from the binaries. For the radiation of vector boson, the mass is restricted by $M_{Z^\prime}<\Omega \simeq10^{-19}eV$ are the orbital frequencies of the compact star binaries. Using the formula of orbital period decay, we obtain constraints on the coupling constant of the gauge boson in the gauged $L_\mu-L_\tau$ theory for the four compact binary systems. For vector gauge boson muon coupling we find that for $M_{Z^\prime}<10^{-19}eV$, constraints on the coupling constant is $g<\mathcal{O}(10^{-20})$. We also obtain the exclusion plots of the massive vector proca field and the gauge field which can couple to muons.

[70]  arXiv:2003.13724 (cross-list from gr-qc) [pdf, ps, other]

Title: Rectifying Einstein-Gauss-Bonnet Inflation in View of GW170817

Authors: S.D. Odintsov, V.K. Oikonomou, F.P. Fronimos

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

In this work we introduce a new theoretical framework for Einstein-Gauss-Bonnet theories of gravity, which results to particularly elegant, functionally simple and transparent gravitational equations of motion, slow-roll indices and the corresponding observational indices. The main requirement is that the Einstein-Gauss-Bonnet theory has to be compatible with the GW170817 event, so the gravitational wave speed $c_T^2$ is required to be $c_T^2\simeq 1$ in natural units. This assumption was also made in a previous work of ours, but in this work we express all the related quantities as functions of the scalar field. The constraint $c_T^2\simeq 1$ restricts the functional form of the scalar Gauss-Bonnet coupling function $\xi(\phi)$ and of the scalar potential $V(\phi)$, which must satisfy a differential equation. However, by also assuming that the slow-roll conditions hold true, the resulting equations of motion and the slow-roll indices acquire particularly simple forms, and also the relation that yields the $e$-foldings number is $N=\int_{\phi_i}^{\phi_f}\xi''/\xi'd \phi$, a fact that enables us to perform particularly simple calculations in order to study the inflationary phenomenological implications of several models. As it proves, the models we presented are compatible with the observational data, and also satisfy all the assumptions made during the process of extracting the gravitational equations of motion. More interestingly, we also investigated the phenomenological implications of an additional condition $\xi'/\xi''\ll 1$, which is motivated by the slow-roll conditions that are imposed on the scalar field evolution and on the Hubble rate, in which case the study is easier. Our approach opens a new window in viable Einstein-Gauss-Bonnet theories of gravity.

[71]  arXiv:2003.13730 (cross-list from gr-qc) [pdf, other]

Title: Critical collapse in K-essence models

Authors: Radouane Gannouji, Yolbeiker Rodríguez Baez

Comments: 16 pages, 6 figures, JHEP style

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

We study gravitational collapse in K-essence model with shift symmetry. For these models, we have the formation of two types of horizons, event and sonic. For the particular case $K(X)=X+\beta X^2$ we found three different regimes. In the weak field regime the scalar field disperses to infinity, in the very strong regime both horizons form at the same time and finally for the intermediate regime, the sonic horizon could form first or both horizons form at the same time. The threshold of formation of black hole is found in the regime where the sonic horizon forms first. We observe a universal behavior with scaling parameter $\gamma\simeq 0.51$. Interestingly this universal behavior is already encoded in the sonic horizon much before the black hole forms and therefore the emergence of the event horizon.

[72]  arXiv:2003.13744 (cross-list from hep-ph) [pdf, other]

Title: Simple Hidden Sector Dark Matter

Authors: Patrick Barnes, Zachary Johnson, Aaron Pierce, Bibhushan Shakya

Comments: 28 pages+appendix, 10 figures

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

A hidden sector that kinetically mixes with the Minimal Supersymmetric Standard Model provides simple and well-motivated dark matter candidates that possess many of the properties of a traditional weakly interacting massive particle (WIMP). These supersymmetric constructions can also provide a natural explanation for why the dark matter is at the weak scale - even if it resides in a hidden sector. In the hidden sector, a natural pattern of symmetry breaking generally makes particles and their superpartners lie around the same mass scale, opening novel possibilities for a variety of cosmological histories and complex indirect detection signatures.

[73]  arXiv:2003.13838 (cross-list from physics.atom-ph) [pdf, other]

Title: High-Precision Determination of Oxygen-K$α$ Transition Energy Excludes Incongruent Motion of Interstellar Oxygen

Authors: M. A. Leutenegger, S. Kühn, P. Micke, R. Steinbrügge, J. Stierhof, C. Shah, N.~Hell, M. Bissinger, M. Hirsch, R. Ballhausen, M. Lang, C. Gräfe, S. Wipf, R. Cumbee, G. L. Betancourt-Martinez, S. Park, V. A. Yerokhin, A. Surzhykov, W. C. Stolte, J. Niskanen, M. Chung, F. S. Porter, T. Stöhlker, T. Pfeifer, J. Wilms, G. V. Brown, J. R. Crespo López-Urrutia, S. Bernitt

Comments: Submitted to PRL. 7 pages, 3 figures

Subjects: Atomic Physics (physics.atom-ph); Instrumentation and Methods for Astrophysics (astro-ph.IM)

We demonstrate a widely applicable technique to absolutely calibrate the energy scale of x-ray spectra with experimentally well-known and accurately calculable transitions of highly charged ions, allowing us to measure the K-shell Rydberg spectrum of molecular O$_2$ with 6 meV uncertainty. We reveal a systematic $\sim$450 meV shift from previous literature values, and settle an extraordinary discrepancy between astrophysical and laboratory measurements of neutral atomic oxygen, the latter being calibrated against the aforementioned O$_2$ literature values. Because of the widespread use of such, now deprecated, references, our method impacts on many branches of x-ray absorption spectroscopy. Moreover, it potentially reduces absolute uncertainties there to below the meV level.

[74]  arXiv:2003.13862 (cross-list from physics.comp-ph) [pdf, ps, other]

Title: Technologies for supporting high-order geodesic mesh frameworks for computational astrophysics and space sciences

Authors: V. Florinski, D. S. Balsara, S. Garain, K. F. Gurski

Comments: 41 pages, 18 figures

Journal-ref: Comput. Astrophys. Cosmol. 7, 1 (2020)

Subjects: Computational Physics (physics.comp-ph); Instrumentation and Methods for Astrophysics (astro-ph.IM)

Many important problems in astrophysics, space physics, and geophysics involve flows of (possibly ionized) gases in the vicinity of a spherical object, such as a star or planet. The geometry of such a system naturally favors numerical schemes based on a spherical mesh. Despite its orthogonality property, the polar (latitude-longitude) mesh is ill suited for computation because of the singularity on the polar axis, leading to a highly non-uniform distribution of zone sizes. The consequences are (a) loss of accuracy due to large variations in zone aspect ratios, and (b) poor computational efficiency from a severe limitations on the time stepping. Geodesic meshes, based on a central projection using a Platonic solid as a template, solve the anisotropy problem, but increase the complexity of the resulting computer code. We describe a new finite volume implementation of Euler and MHD systems of equations on a triangular geodesic mesh (TGM) that is accurate up to fourth order in space and time and conserves the divergence of magnetic field to machine precision. The paper discusses in detail the generation of a TGM, the domain decomposition techniques, three-dimensional conservative reconstruction, and time stepping.

[75]  arXiv:2003.13906 (cross-list from quant-ph) [pdf, ps, other]

Title: Quantum sensing with milligram scale optomechanical systems

Authors: Yuta Michimura, Kentaro Komori

Comments: 14 pages, 6 figures

Subjects: Quantum Physics (quant-ph); Instrumentation and Methods for Astrophysics (astro-ph.IM); Optics (physics.optics)

Probing the boundary between classical and quantum mechanics has been one of the central themes in modern physics. Recently, experiments to precisely measure the force acting on milligram scale oscillators with optical cavities are attracting interest as promising tools to test quantum mechanics, decoherence mechanisms, and gravitational physics. In this paper, we review the present status of experiments using milligram scale optomechanical systems. We compare the feasibility of reaching the quantum regime with a pendulum, torsion pendulum, and optically levitated mirror. Considerations for designing a high $Q$ pendulum, condition for torsion pendulums to have better force sensitivity than pendulums, and constraints in designing optical levitation of a mirror are presented.

[76]  arXiv:2003.13935 (cross-list from gr-qc) [pdf, ps, other]

Title: Turnaround radius in scalar-tensor gravity with quasilocal mass

Authors: Valerio Faraoni, Andrea Giusti, Jeremy Côté

Comments: 8 pages, no figures

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

Following an existing procedure in general relativity, the turnaround radius of a spherical structure is studied in scalar-tensor gravity using a new prescription for the analog of the Hawking-Hayward quasilocal mass in this class of theories. Contrary to the usual study of radial timelike geodesics, this procedure has the advantage of being gauge-independent.

[77]  arXiv:2003.13963 (cross-list from hep-ph) [pdf, ps, other]

Title: Inflaton as the Affleck-Dine Baryogenesis Field in Hilltop Supernatural Inflation

Authors: Chia-Min Lin, Kazunori Kohri

Comments: 15 pages, 9 figures

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

In this paper, we investigate the parameter space in the framework of hilltop supernatural inflation in which the inflaton field can play the role of Affleck-Dine (AD) field to produce successful baryogenesis. The suitable value of reheating temperature could coincide with the reheating temperature required to produce LSP dark matter. The baryon isocurvature perturbation is shown to be negligible. We consider $p=3$, $p=4$ and $p=6$ type III hilltop inflation and discuss how to connect the models to supersymmetric theories.

[78]  arXiv:2003.13981 (cross-list from physics.pop-ph) [pdf, ps, other]

Title: The search for life and a new logic

Authors: Douglas Scott, Ali Frolop

Comments: 3 pages

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

Exploring the Universe is one of the great unifying themes of humanity. Part of this endeavour is the search for extraterrestrial life. But how likely is it that we will find life, or that if we do it will be similar to ourselves? And therefore how do we know where and how to look? We give examples of the sort of reasoning that has been used to narrow and focus this search and we argue that obvious extensions to that logical framework will result in greater success.

[79]  arXiv:2003.14073 (cross-list from gr-qc) [pdf, ps, other]

Title: Polarized initial states of primordial gravitational waves

Authors: Sugumi Kanno, Jiro Soda

Comments: 6 pages. Invited contribution to appear in a special issue on "Symmetry with Gravity and Particle Theories" in Symmetry

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

Polarizations of primordial gravitational waves can be relevant when considering inflationary universe in modified gravity or when matter fields survive during inflation. Such polarizations have been discussed in the Bunch-Davies vacuum. Instead of taking into account dynamical generation of polarizations of gravitational waves, in this paper, we consider polarized initial states constructed from $SU(2)$ coherent states. We then evaluate the power spectrums of the primordial gravitational waves in the states.

[80]  arXiv:2003.14108 (cross-list from gr-qc) [pdf, ps, other]

Title: Perturbations and Linearisation Stability of Closed Friedmann Universes

Authors: Hyerim Noh, Jai-chan Hwang, John D. Barrow

Comments: 19 pages, no figure

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

We consider perturbations of closed Friedmann universes. Perturbation modes of two lowest wavenumbers ($L=0$ and $1$) are generally known to be fictitious, but here we show that both are physical. The issue is more subtle in Einstein static universes where closed background space has a time-like Killing vector with the consequent occurrence of linearization instability. Solutions of the linearized equation need to satisfy the Taub constraint on a quadratic combination of first-order variables. We evaluate the Taub constraint in the two available fundamental gauge conditions, and show that in both gauges the $L\geq 1$ modes should accompany the $L=0$ (homogeneous) mode for vanishing sound speed, $c_{s}$. For $c_{s}^{2}>1/5$ (a scalar field supported Einstein static model belongs to this case with $c_s^2 = 1$), the $L\geq 2$ modes are known to be stable. In order to have a stable Einstein static evolutionary stage in the early universe, before inflation and without singularity, although the Taub constraint does not forbid it, we need to find a mechanism to suppress the unstable $L=0$ and $L=1$ modes.

[81]  arXiv:2003.14115 (cross-list from nucl-th) [pdf, ps, other]

Title: Light Neutral Clusters in Supernova Matter

Authors: I.V. Panov, A.V. Yudin

Comments: 16 pages, 3 figs

Journal-ref: Physics of Atomic Nuclei, 2019, Vol. 82, No. 5, pp. 483-490

Subjects: Nuclear Theory (nucl-th); Solar and Stellar Astrophysics (astro-ph.SR)

The role of weakly bound neutral clusters, such as dineutrons and tetraneutrons, in matter of high density and high temperature is discussed. Under such conditions, which are characteristic of core-collapse supernovae, the lifetime of multineutrons may prove to be sufficiently long for them to have a pronounced effect on the formation of the chemical composition. The influence of the multineutron binding energy and other nuclear properties on the magnitude of the effect being considered is examined.

[82]  arXiv:2003.14248 (cross-list from physics.ins-det) [pdf, other]

Title: Liquid argon scintillation response to electronic recoils between $2.8$--$1275~{\rm keV}$ in a high light yield single-phase detector

Authors: M.Kimura, K.Aoyama, M.Tanaka, K.Yorita

Comments: 10 pages, 13 figures, 2 tables

Subjects: Instrumentation and Detectors (physics.ins-det); Instrumentation and Methods for Astrophysics (astro-ph.IM)

We measure the liquid argon scintillation response to electronic recoils in the energy range of $2.82$ to $1274.6~{\rm keV}$. The single-phase detector with a large optical coverage used in this measurement yields $12.6 \pm 0.3 ~ (11.1 \pm 0.3)~{\rm photoelectron/keV}$ for $661.7~{\rm keV}$ $\gamma$-ray events based on a photomultiplier tube single photoelectron response modeling with a Gaussian plus an additional exponential terms (with only Gaussian term). It is exposed to a variety of calibration sources such as $^{137}{\rm Cs}$ and $^{241}{\rm Am}$ $\gamma$-ray emitters, and $^{252}{\rm Cf}$ fast neutron emitter that induces quasimonoenergetic $\gamma$-rays through a $(n, n'\gamma)$ reaction with $^{19}{\rm F}$ in polytetrafluoroethylene. In addition, the high light yield enables identification of the $2.82~{\rm keV}$ peak of $^{37}{\rm Ar}$, a cosmogenic isotope in atmospheric argon. The scintillation yield and energy resolution of the detector are obtained by the full-absorption peaks. We find up to approximately $25\%$ shift in the scintillation efficiency across the energy range and less than $3\%$ of the energy resolution for the $661.7~{\rm keV}$ line. The energy dependent scintillation quenching can be attributed by the electron-ion recombination process, and is discussed by an analogy to the dependence of liquid xenon. The Thomas-Imel Box model with its constant parameter $\varsigma=0.07 ^{+0.03} _{-0.02}$ is found to explain the results below $200~{\rm keV}$.

[83]  arXiv:2003.14255 (cross-list from gr-qc) [pdf, other]

Title: Cosmological Constant in Coherent Quantum Gravity

Authors: Craig Hogan

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

It is argued that quantum states of geometry, like those of particles, should be coherent on light cones of any size. An exact classical solution, the gravitational shock wave of a relativistic point particle, is used to estimate gravitational drag from coherent energy flows, and the expected gravitational effect of virtual transverse vacuum energy fluctuations on surfaces of causal diamonds. It is proposed that the appropriately spacetime-averaged gravitational effect of the Standard Model vacuum state leads to the observed small nonzero value of the cosmological constant, dominated by gravitational drag of virtual gluonic strings at the strong interaction scale.

Replacements for Wed, 1 Apr 20

[84]  arXiv:1710.10213 (replaced) [pdf, other]

Title: Kepler's Dark Worlds: a Low Albedo for an Ensemble of Neptunian and Terran Exoplanets

Authors: Tiffany Jansen, David Kipping

Comments: Accepted for publication in MNRAS. Phase curves and phasma code available at this https URL and forward model available at this https URL

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

[85]  arXiv:1810.05139 (replaced) [pdf, other]

Title: Climates of Warm Earth-like Planets II: Rotational 'Goldilocks' Zones for Fractional Habitability and Silicate Weathering

Authors: Tiffany Jansen, Caleb Scharf, Michael Way, Anthony Del Genio

Comments: 11 pages, 10 figures, accepted for publication in ApJ

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

[86]  arXiv:1901.06582 (replaced) [pdf, other]

Title: Inferring the parallax of Westerlund 1 from Gaia DR2

Authors: Mojgan Aghakhanloo, Jeremiah W. Murphy, Nathan Smith, John Parejko, Mariangelly Díaz-Rodríguez, Maria R. Drout, Jose H. Groh, Joseph Guzman, Keivan G. Stassun

Comments: 14 pages, 10 figures

Journal-ref: 2020MNRAS.492.2497A

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

[87]  arXiv:1904.04471 (replaced) [pdf, ps, other]

Title: Recursion relations for gravitational lensing

Authors: Ben David Normann, Chris Clarkson

Comments: 18 pages, 1 figure

Journal-ref: General Relativity and Gravitation 52 (2020), 3

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

[88]  arXiv:1904.04570 (replaced) [pdf, other]

Title: Bursts of Gravitational Waves due to Crustquake from Pulsars

Authors: Biswanath Layek, Pradeepkumar Yadav

Comments: 8 pages, 1 table, comments are welcome!

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

[89]  arXiv:1905.02166 (replaced) [pdf, other]

Title: A Cautionary Tale of Attenuation in Star Forming Regions

Authors: M. Molina (1,2), N. Ajgaonkar (3), R. Yan (3), R. Ciardullo (1), C. Gronwall (1), M. Eracleous (1), M. Boquien (4), D. P. Schneider (1) (1 Penn State, 2 Montana State U, 3 U Kentucky, 4 U Antofagasta)

Comments: Accepted to MNRAS March 29, 2020

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

[90]  arXiv:1905.10136 (replaced) [pdf, ps, other]

Title: Multicomponent Dark Matter in the Light of CALET and DAMPE

Authors: Chao-Qiang Geng, Da Huang, Lu Yin

Comments: 22 pages, 4 figures; Comments are added and typos are fixed

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

[91]  arXiv:1908.10451 (replaced) [pdf, other]

Title: Sensitivity of the Prime-Cam Instrument on the CCAT-prime Telescope

Authors: Steve K. Choi, Jason Austermann, Kaustuv Basu, Nicholas Battaglia, Frank Bertoldi, Dongwoo T. Chung, Nicholas F. Cothard, Shannon Duff, Cody J. Duell, Patricio A. Gallardo, Jiansong Gao, Terry Herter, Johannes Hubmayr, Michael D. Niemack, Thomas Nikola, Dominik Riechers, Kayla Rossi, Gordon J. Stacey, Jason R. Stevens, Eve M. Vavagiakis, Michael Vissers, Samantha Walker

Comments: Version accepted for publication by Journal of Low Temperature Physics; updates on FPI detectors, more details given on sensitivity calculations

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

[92]  arXiv:1910.02080 (replaced) [pdf, other]

Title: Axiogenesis

Authors: Raymond T. Co, Keisuke Harigaya

Comments: 6+10 pages, 1+2 figures; v2: a simplified model and references added, matches journal version

Journal-ref: Phys. Rev. Lett. 124, 111602 (2020)

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

[93]  arXiv:1910.12754 (replaced) [pdf, other]

Title: Deep XMM-Newton observations of the northern disk of M31 II: Tracing the hot interstellar medium

Authors: Patrick J. Kavanagh, Manami Sasaki, Dieter Breitschwerdt, Miguel A. de Avillez, Miroslav D. Filipovic, Timothy Galvin, Frank Haberl, Despina Hatzidimitriou, Martin Henze, Paul P. Plucinsky, Sara Saeedi, Kirill V. Sokolovsky, Benjamin F. Williams

Comments: 23 pages, 14 figures, accepted for publication in Astronomy & Astrophysics

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

[94]  arXiv:1911.07593 (replaced) [pdf, other]

Title: Quasi-Normal Modes of Hairy Scalar Tensor Black Holes: Odd Parity

Authors: Oliver J. Tattersall

Comments: Updated to match Classical and Quantum Gravity accepted version

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

[95]  arXiv:1911.09691 (replaced) [pdf, other]

Title: Modeling the magnetized Local Bubble from dust data

Authors: V. Pelgrims, K. Ferrière, F. Boulanger, R. Lallement, L. Montier

Comments: v2 closely match the final and accepted version at A&A

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

[96]  arXiv:1911.10078 (replaced) [pdf, other]

Title: Probing a cosmic axion-like particle background within the jets of active galactic nuclei

Authors: Ahmed Ayad, Geoff Beck

Comments: This work is prepared for submission to JCAP

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

[97]  arXiv:1912.01895 (replaced) [pdf, other]

Title: Where Did They Come From, Where Did They Go. Grazing Fireballs

Authors: P.M. Shober, T. Jansen-Sturgeon, E.K. Sansom, H.A.R. Devillepoix, M.C. Towner, P.A. Bland, M. Cupák, R.M. Howie, B.A.D. Hartig

Comments: Accepted for publication in AJ

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

[98]  arXiv:1912.04887 (replaced) [pdf, other]

Title: An excessively massive thick disc of the enormous edge-on lenticular galaxy NGC7572

Authors: Anastasia V. Kasparova, Ivan Yu. Katkov, Igor V. Chilingarian

Comments: 16 pages, 10 figures, submitted to MNRAS

Journal-ref: MNRAS, 2020, Volume 493, Issue 4, p.5464-5478

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

[99]  arXiv:1912.09709 (replaced) [pdf, ps, other]

Title: Rotating black holes with an anisotropic matter field

Authors: Hyeong-Chan Kim, Bum-Hoon Lee, Wonwoo Lee, Youngone Lee

Comments: 20 pages, 4 figures, reference added

Journal-ref: Physical Review D 101, 064067 (2020)

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

[100]  arXiv:1912.09778 (replaced) [pdf, other]

Title: From the bulge to the outer disc: StarHorse stellar parameters, distances, and extinctions for stars in APOGEE DR16 and other spectroscopic surveys

Authors: A. B. A. Queiroz, F. Anders, C. Chiappini, A. Khalatyan, B. X. Santiago, M. Steinmetz, M. Valentini, A. Miglio, D. Bossini, B. Barbuy, I. Minchev, D. Minniti, D. A. García Hernández, M. Schultheis, R. L. Beaton, T. C. Beers, D. Bizyaev, J. R. Brownstein, K. Cunha, J. G. Fernández-Trincado, P. M. Frinchaboy, R. R. Lane, S. R. Majewski, D. Nataf, C. Nitschelm, K. Pan, A. Roman-Lopes, J. S. Sobeck, G. Stringfellow, O. Zamora

Comments: 17 pages, 11 figures. Resubmitted to A&A after referee report. Data products are available at this https URL, (doi:10.17876/data/2020_2)

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

[101]  arXiv:1912.10585 (replaced) [pdf, ps, other]

Title: Gravitational atoms: general framework for the construction of multistate axially symmetric solutions of the Schrödinger-Poisson system

Authors: F. S. Guzmán, L. Arturo Ureña-López

Comments: 6 pages, 14 eps figures. Accepted for publication as Rapid Communication in Phys. Rev. D

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

[102]  arXiv:1912.10859 (replaced) [pdf, ps, other]

Title: Non-adiabatic cosmological production of ultra-light Dark Matter

Authors: Nathan Herring, Daniel Boyanovsky, Andrew R. Zentner

Comments: Discussion on isocurvature perturbations. To appear in PRD

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

[103]  arXiv:2001.00563 (replaced) [pdf, other]

Title: Using Data Imputation for Signal Separation in High Contrast Imaging

Authors: Bin Ren, Laurent Pueyo, Christine Chen, Élodie Choquet, John H. Debes, Gaspard Duchêne, François Ménard, Marshall D. Perrin

Comments: 18 pages, 9 figures, ApJ published. Modified AASTeX template at this https URL

Journal-ref: ApJ 892 (2020) 74

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

[104]  arXiv:2001.02361 (replaced) [pdf, other]

Title: The Effects of Tilt on the Images of Black Hole Accretion Flows

Authors: Christopher J. White, Jason Dexter, Omer Blaes, Eliot Quataert

Comments: 15 pages, 15 figures, 1 table; accepted by ApJ

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

[105]  arXiv:2001.10018 (replaced) [pdf, other]

Title: Probing the thermal state of the intergalactic medium at $z>5$ with the transmission spikes in high-resolution Ly$α$ forest spectra

Authors: Prakash Gaikwad, Michael Rauch, Martin G. Haehnelt, Ewald Puchwein, James S. Bolton, Laura C. Keating, Girish Kulkarni, Vid Iršič, Eduardo Bañados, George D. Becker, Elisa Boera, Fakhri S. Zahedy, Hsiao-Wen Chen, Robert F. Carswell, Jonathan Chardin, Alberto Rorai

Comments: 20 pages (+10 pages appendices), 12 figures (+14 figures appendices); Accepted in MNRAS; Main results are summarized in Fig. 10, Fig. 12 and Table 3

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

[106]  arXiv:2001.10580 (replaced) [pdf, other]

Title: Detection of the phase curve and occultation of WASP-100b with TESS

Authors: Tiffany Jansen, David Kipping

Comments: 14 pages, 6 figures, 3 tables. Accepted for publication by MNRAS

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

[107]  arXiv:2001.10836 (replaced) [pdf, ps, other]

Title: On the Cooling Flow Problem in the Gaseous Halo of the Milky Way

Authors: Xiang-Er Fang, Fulai Guo, Ye-Fei Yuan

Comments: Slightly revised version, accepted for publication in ApJ. 15 pages, 13 figures

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

[108]  arXiv:2002.03625 (replaced) [pdf, other]

Title: Post-Born corrections to the one-point statistics of (CMB) lensing convergence obtained via large deviation theory

Authors: Alexandre Barthelemy, Sandrine Codis, Francis Bernardeau

Comments: Accepted for publication in MNRAS, 17 pages, comments welcome

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

[109]  arXiv:2002.07586 (replaced) [pdf, ps, other]

Title: Geodesics of the hyperbolically symmetric black hole

Authors: L. Herrera, A. Di Prisco, J. Ospino, L. Witten

Comments: 8 pages Revtex. 4 figures. Some typos corrected. Published in Phys.Rev.D

Journal-ref: Phys. Rev. D101, 064071, (2020)

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

[110]  arXiv:2002.08624 (replaced) [pdf, other]

Title: Anticorrelated temperature-density profiles in the quiet solar corona and coronal mass ejections: Approach based on the spine-type Hamiltonians

Authors: Yurii V. Dumin

Comments: PDFLaTeX, elsarticle documentclass, 12 pages, 5 PDF figures; v2: minor textual corrections, 1 bibliographic reference added, submitted to Advances in Space Research

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

[111]  arXiv:2003.01222 (replaced) [pdf, other]

Title: The Koala: A Fast Blue Optical Transient with Luminous Radio Emission from a Starburst Dwarf Galaxy at $z=0.27$

Authors: Anna Y. Q. Ho (1), D. A. Perley (2) S. R. Kulkarni (1), I. Andreoni (1), E. C. Bellm (3), K. B. Burdge (1), P. Chandra (4), M. Coughlin, K. De (1), D. Z. J. Dong (1), V. Z. Golkhou (3,6,7), M. J. Graham (1), D. D. Fredericks (8), G. Helou (9), A. Horesh (10), R. R. Laher (9), F. Masci (9), A. Ridnaia (8), B. Rusholme (9), D. L. Shupe (9), D. S. Svinkin (8) ((1) Caltech, (2) LJMU, (3) DIRAC Institute, UW, (4) NCRA, (5) U. Minnesota, (6) eScience Institute, (7) Moore-Sloan, WRF Innovation, DIRAC Fellow, (8) Ioffe Institute, (9) IPAC, (10) Racah Institute)

Comments: 21 pages, 10 figures. Submitted to ApJ on 2 March 2020. Updated with a correction to Equation 3 on 31 March. Comments welcome!

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

[112]  arXiv:2003.04086 (replaced) [pdf, other]

Title: Silicon photomultiplers in Very High Energy gamma-ray astrophysics

Authors: D. Guberman, R. Paoletti

Comments: Accepted for publication in JINST. 9 pages, 7 figures. Proceedings of the 5th INFIERI

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

[113]  arXiv:2003.06429 (replaced) [pdf, other]

Title: Absorption line abundances in the SMC-like galaxy UGC 5282: evidence for ISM dilution from inflows on kiloparsec scales

Authors: David V. Bowen, Todd M. Tripp, Edward B. Jenkins, Max Pettini, Doron Chelouche, Renyue Cen, Donald G. York

Comments: Accepted for publication in ApJ. This version: typos corrected, references updated

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

[114]  arXiv:2003.07360 (replaced) [pdf, other]

Title: Gravitational waves from first-order cosmological phase transitions: lifetime of the sound wave source

Authors: John Ellis, Marek Lewicki, José Miguel No

Comments: 32 pages, 14 figures

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

[115]  arXiv:2003.07647 (replaced) [pdf, other]

Title: Non-linear spherical collapse in tachyon models, and a comparison of collapse in tachyon and quintessence models of dark energy

Authors: Manvendra Pratap Rajvanshi, J. S. Bagla

Comments: 15 Pages, 11 Figures. Version 2: added few references. Comments welcome

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

[116]  arXiv:2003.10203 (replaced) [pdf, ps, other]

Title: Violation of slow-roll in non-minimal inflation

Authors: Tomo Takahashi, Tommi Tenkanen, Shuichiro Yokoyama

Comments: 25 pages, 10 figures, minor corrections and references added

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

[117]  arXiv:2003.10205 (replaced) [pdf, ps, other]

Title: Geometric optics in the presence of axion-like particles in curved space-time

Authors: Dominik J. Schwarz, Jishnu Goswami, Aritra Basu

Comments: 3 pages, reference added, typos corrected

Subjects: High Energy Physics - Phenomenology (hep-ph); Instrumentation and Methods for Astrophysics (astro-ph.IM); General Relativity and Quantum Cosmology (gr-qc)

[118]  arXiv:2003.11121 (replaced) [pdf, other]

Title: Carnegie Supernova Project-II: A new method to photometrically identify sub-types of extreme Type Ia Supernovae

Authors: C. Ashall, J. Lu, C. Burns, E. Y. Hsiao, M. Stritzinger, N. B. Suntzeff, M. M. Phillips, E. Baron, C. Contreras, S. Davis, L. Galbany, P. Hoeflich, S. Holmbo, N. Morrell, E. Karamehmetoglu, K. Krisciunas, S. Kumar, M. Shahbandeh, S. Uddin

Comments: accepted for publication in ApjL, small updates to text from previous version

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

[119]  arXiv:2003.11889 (replaced) [pdf, other]

Title: Side-On transition radiation detector: a detector prototype for TeV energy scale calibration of calorimeters in space

Authors: Bo Huang, Hongbang Liu, Xuefeng Huang, Ming Xu, Yongwei Dong, Xiaotong Wei, Xiwen Liu, Huanbo Feng, Qinhe Yang, Jianyu Gu, Shuai Chen, Xiaochuan Xie, Jin Zhang, Yongbo Huang, Enwei Liang

Comments: 13 pages, 10 figures, 2 tables

Journal-ref: Nuclear Inst. and Methods in Physics Research, A 962 (2020) 163723

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Instrumentation and Detectors (physics.ins-det)

[120]  arXiv:2003.12117 (replaced) [pdf, other]

Title: STRIDES: Spectroscopic and photometric characterization of the environment and effects of mass along the line of sight to the gravitational lenses DES J0408-5354 and WGD 2038-4008

Authors: E. J. Buckley-Geer, H. Lin, C. Rusu, J. Poh, A. Palmese, A. Agnello, L. Christensen, J. Frieman, A. J. Shajib, T. Treu, T. Collett, S. Birrer, T. Anguita, C. D. Fassnacht, G. Meylan, S. Mukherjee, K. C. Wong, M. Aguena, S. Allam, S. Avila, E. Bertin, S. Bhargava, D. Brooks, A. Carnero Rosell, M. Carrasco Kind, J. Carretero, F. J. Castander, M. Costanzi, L. N. da Costa, J. De Vicente, S. Desai, H. T. Diehl, P. Doel, T. F. Eifler, S. Everett, B. Flaugher, P. Fosalba, J. García-Bellido, E. Gaztanaga, D. Gruen, R. A. Gruendl, J. Gschwend, G. Gutierrez, S. R. Hinton, K. Honscheid, D. J. James, K. Kuehn, N. Kuropatkin, M. A. G. Maia, J. L. Marshall, P. Melchior, F. Menanteau, R. Miquel, R. L. C. Ogando, F. Paz-Chinchón, A. A. Plazas, E. Sanchez, V. Scarpine, M. Schubnell, S. Serrano, et al. (8 additional authors not shown)

Comments: 40 pages, 18 figures Added missing author to the author list

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

[121]  arXiv:2003.12583 (replaced) [pdf, other]

Title: Continuum-Fitting the X-ray Spectra of Tidal Disruption Events

Authors: Sixiang Wen, Peter G. Jonker, Nicholas C. Stone, Ann I. Zabludoff, Dimitrios Psaltis

Comments: Submitted to ApJ. Welcome for comments

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

[122]  arXiv:2003.12634 (replaced) [pdf, ps, other]

Title: Very Slow Rotators from Tidally Synchronized Binaries

Authors: D. Nesvorny, D. Vokrouhlicky, W. F. Bottke, H. F. Levison, W. M. Grundy

Comments: accepted in ApJL

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

[123]  arXiv:2003.13434 (replaced) [pdf, other]

Title: String-inspired Teleparallel Cosmology

Authors: Sebastian Bahamonde, Mihai Marciu, Sergei D. Odintsov, Prabir Rudra

Comments: 18 pages. Small important typo fixed in the scalars

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

[124]  arXiv:2003.13602 (replaced) [pdf, other]

Title: On the formation of hydrogen-deficient low-mass white dwarfs

Authors: Tiara Battich, Leandro G. Althaus, Alejandro H. Córsico

Comments: 7 pages, 7 figures. Accepted for publication in A&A

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

[125]  arXiv:2003.13625 (replaced) [pdf, other]

Title: SDSS-IV MaNGA: Stellar population correlates with stellar root-mean-square velocity $V_{\rm rms}$ gradients or total-density-profile slopes at fixed effective velocity dispersion $σ_{\rm e}$

Authors: Shengdong Lu, Michele Cappellari, Shude Mao, Junqiang Ge, Ran Li

Comments: 7 pages, 4 figures; Submitted to MNRAS

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

• New submissions
• Cross-lists
• Replacements