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New submissions for Fri, 17 Jan 20

[1]  arXiv:2001.05498 [pdf, ps, other]

Title: Suppression of H2-cooling in protogalaxies aided by trapped Lyα cooling radiation

Authors: Jemma Wolcott-Green, Zoltan Haiman, Greg L. Bryan

Comments: 8 pages, 5 figures

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

We study the thermal evolution of UV-irradiated atomic cooling haloes using high-resolution three-dimensional hydrodynamic simulations. We consider the effect of H^- photodetachment by Ly{\alpha} cooling radiation trapped in the optically-thick cores of three such haloes, a process which has not been included in previous simulations. H^- is a precursor of molecular hydrogen, and therefore, its destruction can diminish the H2 abundance and cooling. Using a simple high-end estimate for the trapped Ly{\alpha} energy density, we find that H^- photodetachment by Ly{\alpha} decreases the critical UV flux for suppressing H2-cooling by up to a factor of \approx 5. With a more conservative estimate of the Ly{\alpha} energy density, we find the critical flux is decreased only by ~15-50 percent. Our results suggest that Ly{\alpha} radiation may have an important effect on the thermal evolution of UV-irradiated haloes, and therefore on the potential for massive black hole formation.

[2]  arXiv:2001.05499 [pdf, other]

Title: Probing the circumnuclear absorbing medium of the buried AGN in NGC 1068 through NuSTAR observations

Authors: A. Zaino (1), S. Bianchi (1), A. Marinucci (2), G. Matt (1), F. E. Bauer (3,4,5), W. N. Brandt (6,7,8), P. Gandhi (9), M. Guainazzi (10), K. Iwasawa (11), S. Puccetti (2), C. Ricci (12,13), D. J. Walton (14) ((1) Dipartimento di Matematica e Fisica, Università degli Studi Roma Tre, (2) Agenzia Spaziale Italiana, (3) Instituto de Astrofísica and Centro de Astroingeniería, Pontificia Universidad Católica de Chile, (4) Millennium Institute of Astrophysics, (5) Space Science Institute, (6) Department of Astronomy and Astrophysics, The Pennsylvania State University, (7) Institute for Gravitation and the Cosmos, The Pennsylvania State University, (8) Department of Physics, The Pennsylvania State University, (9) Department of Physics and Astronomy, University of Southampton, (10) European Space Agency, (11) ICREA and Institut de Ciències del Cosmos, Universitat de Barcelona, (12) Núcleo de Astronomía de la Facultad de Ingeniería, Universidad Diego Portales, (13) Kavli Institute for Astronomy and Astrophysics, Peking University, (14) Institute of Astronomy, University of Cambridge)

Comments: 14 pages, 12 figures, 7 tables. MNRAS in press

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

We present the results of the latest NuSTAR monitoring campaign of the Compton-thick Seyfert 2 galaxy NGC 1068, composed of four $\sim$50 ks observations performed between July 2017 and February 2018 to search for flux and spectral variability on timescales from 1 to 6 months. We detect one unveiling and one eclipsing event with timescales less than 27 and 91 days, respectively, ascribed to Compton-thick material with $N_H=(1.8\pm0.8)\times10^{24}$ cm$^{-2}$ and $N_H\geq(2.4\pm0.5)\times10^{24}$ cm$^{-2}$ moving across our line of sight. This gas is likely located in the innermost part of the torus or even further inward, thus providing further evidence of the clumpy structure of the circumnuclear matter in this source. Taking advantage of simultaneous Swift-XRT observations, we also detected a new flaring ULX, at a distance $d\sim$30" (i.e. $\sim$2 kpc) from the nuclear region of NGC 1068, with a peak X-ray intrinsic luminosity of $(3.0\pm0.4)\times10^{40}$ erg s$^{-1}$ in the 2-10 keV band.

[3]  arXiv:2001.05503 [pdf, other]

Title: The Subhalo Mass Function and Ultralight Bosonic Dark Matter

Authors: Katelin Schutz

Comments: 8 pages, 1 figure

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

Warm dark matter has recently become increasingly constrained by observational inferences about the low-mass end of the subhalo mass function, which would be suppressed by dark matter free streaming in the early Universe. In this work, we point out that a constraint can be placed on ultralight bosonic dark matter (often referred to as "fuzzy dark matter") based on similar considerations. Recent limits on warm dark matter from strong gravitational lensing of quasars and from fluctuations in stellar streams separately translate to a lower limit of $\sim 2.1 \times 10^{-21}$ eV on the mass of an ultralight boson comprising all dark matter. These limits are complementary to constraints on ultralight dark matter from the Lyman-$\alpha$ forest and are subject to a completely different set of assumptions and systematic uncertainties. Taken together, these probes strongly suggest that dark matter with a mass $\sim 10^{-22}$ eV is not a viable way to reconcile differences between cold dark matter simulations and observations of structure on small scales.

[4]  arXiv:2001.05504 [pdf, other]

Title: A Complete Catalogue of Dusty Supernova Remnants

Authors: Hannah Chawner, Haley Gomez, Mikako Matsuura, Matt Smith, Andreas Papageorgiou, Jeonghee Rho, ALberto Noriega-Crespo, Ilse De Looze, Mike Barlow, Phil Cigan, Loretta Dunne, Ken Marsh

Comments: 25 pages, 26 figures. Accepted in MNRAS. For images and details of the complete catalogue see the Appendix at this https URL

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

We search for far-infrared (FIR) counterparts of known supernova remnants (SNRs) in the Galactic plane (360 degrees in longitude and b = +/- 1 deg ) at 70 - 500 micron with Herschel. We detect dust signatures in 39 SNRs out of 190, made up of 13 core-collapse supernovae (CCSNe), including 4 Pulsar Wind Nebulae (PWNe), and 2 Type Ia SNe. A further 24 FIR detected SNRs have unknown types. We confirm the FIR detection of ejecta dust within G350.1-0.3, adding to the known sample of ~10 SNRs containing ejecta dust. We discover dust features at the location of a radio core at the centre of G351.2+0.1, indicating FIR emission coincident with a possible Crab-like compact object, with dust temperature and mass of Td = 45.8 K and Md = 0.18 solar mass, similar to the PWN G54.1+0.3. We show that the detection rate is higher among young SNRs. We produce dust temperature maps of 11 SNRs and mass maps of those with distance estimates, finding dust at temperatures 15 < Td < 40 K. If the dust is heated by shock interactions the shocked gas must be relatively cool and/or have a low density to explain the observed low grain temperatures.

[5]  arXiv:2001.05506 [pdf, other]

Title: SDSS-IV MaNGA: global and local stellar population properties of elliptical galaxies and their assembly histories

Authors: I. Lacerna, H. Ibarra-Medel, V. Avila-Reese, H. M. Hernández-Toledo, J. A. Vázquez-Mata, S. F. Sánchez

Comments: 23 pages and 17 figures without appendix. Submitted to Astronomy & Astrophysics

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

We study the spatially resolved properties of 333 elliptical galaxies with the MaNGA/SDSS-IV survey. The aim is to understand the fundamental processes of formation and quenching of elliptical galaxies. We used the DESI Legacy Imaging Surveys for accurate morphological classification. Based on integrated spectroscopic properties and colors, we classified galaxies into classical "red and dead", recently quenched, and blue star-forming ellipticals (CLEs, RQEs, and BSFs corresponding to 75%, 10%, and 4% of the sample, respectively). We inferred their stellar age and stellar metallicity gradients out to 1.5 effective radius, and reconstructed their global and radial histories of mass growth and star formation. We find the mass- and light-weighted age gradients of CLEs are nearly flat or mildly negative, with small differences between both ages. The respective metallicity gradients are negative, being flatter as less massive are the CLEs. The more massive CLEs assembled earlier and quenched faster than the less massive ones. The CLEs show a weak inside-out growth and a clear inside-out quenching. At masses < $10^{11}$ $M_{\bigodot}$, the age and $Z$ gradients of the RQEs and BSFs are flatter than those of the CLEs but with larger scatters. They show very weak inside-out growth and quenching, being the quenching slow and even not completed at $z\sim$ 0 for the BSFs. Instead, the massive RQEs show an outside-in quenching, and positive gradients in the light-weighted age and stellar metallicities. Our results are consistent with a scenario where the inner parts of CLEs formed by an early and coeval dissipative collapse with a consequent burst of star formation and further quenching, whereas the outer parts continued their assembly likely by dry mergers. We also discuss some evolutionary scenarios for the RQE and BSF galaxies that would agree with their generic results presented here.

[6]  arXiv:2001.05507 [pdf, other]

Title: A SCUBA-2 850$μ$m Survey of Heavily Reddened Quasars at z~2

Authors: Clare F. Wethers, Manda Banerji, Paul C. Hewett, Gareth C. Jones

Comments: 11 pages, 9 figures, MNRAS Accepted

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

We present new 850$\mu$m SCUBA-2 observations for a sample of 19 heavily reddened Type-I quasars at redshifts $z\sim$2 with dust extinctions of A$_{\rm{V}} \simeq 2-6$ mag. Three of the 19 quasars are detected at $>$3$\sigma$ significance corresponding to an 850$\mu$m flux-limit of $\gtrsim$4.8 mJy. Assuming the 850$\mu$m flux is dominated by dust heating due to star formation, very high star formation rates (SFR) of $\sim$2500-4500 M$_\odot$ yr$^{-1}$ in the quasar host galaxies are inferred. Even when considering a large contribution to the 850$\mu$m flux from dust heated by the quasar itself, significant SFRs of $\sim$600-1500 M$_\odot$ yr$^{-1}$ are nevertheless inferred for two of the three detected quasars. We stack the remaining 16 heavily reddened quasars and derive an average 3$\sigma$ upper limit on the SFRs in these quasar host galaxies of $<$880 M$_\odot$ yr$^{-1}$. The number counts of sub-mm galaxies in the total survey area (134.3arcmin$^2$) are consistent with predictions from blank-field surveys. There are, however, individual quasars where we find evidence for an excess of associated sub-mm galaxies. For two quasars, higher spatial resolution and spectroscopic ALMA observations confirm the presence of an excess of sub-mm sources. We compare the 850$\mu$m detection rate of our quasars to both unobscured, ultraviolet luminous quasars as well as the much more obscured population of mid-infrared luminous Hot Dust Obscured Galaxies (HotDOGs). When matched by luminosity and redshift, we find no significant differences in the 850$\mu$m flux densities of these various quasar populations given the current small sample sizes.

[7]  arXiv:2001.05508 [pdf, other]

Title: On the origin of low escape fractions of ionizing radiation from massive star-forming galaxies at high redshift

Authors: Taehwa Yoo, Taysun Kimm, Joakim Rosdahl

Comments: 19 pages, 13 figures, submitted to MNRAS

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

The physical origin of low escape fractions of ionizing radiation derived from Lyman-break galaxies (LBGs) at $z\sim3$--$4$ is not well understood. We perform idealised disc galaxy simulations to understand how galactic properties such as metallicity and gas mass affect the escape of Lyman Continuum (LyC) photons using radiation-hydrodynamic simulations with strong stellar feedback. We find that the luminosity-weighted escape fraction from a metal-poor ($Z=0.002$) galaxy embedded in a halo of mass $M_h\simeq10^{11}\,M_\odot$ is $\left<f_{\rm esc}^{\rm 3D}\right>\simeq7\%$. Roughly half of the LyC photons are absorbed within scales of 100 pc, and the other half is absorbed in the ISM ($\lesssim 2$ kpc). When the metallicity of the gas is increased to $Z=0.02$, the escape fraction is significantly reduced to $\left<f_{\rm esc}^{\rm 3D}\right>\simeq1\%$ because young stars are enshrouded by their birth clouds for a longer time. In contrast, increasing the gas mass by a factor of 5 leads to $\left<f_{\rm esc}^{\rm 3D}\right>\simeq4\%$ because LyC photons are only moderately absorbed by the thicker disc. Our experiments suggest that high metallicity is likely more responsible for the low escape fractions observed in LBGs, supporting the scenario in which the escape fraction is decreasing with increasing halo mass. Finally, negligible correlation is observed between the escape fraction and surface density of star formation or galactic outflow rates.

[8]  arXiv:2001.05512 [pdf, other]

Title: The GALEX Ultraviolet Virgo Cluster Survey (GUViCS) VIII. Diffuse dust in the Virgo intra-cluster space

Authors: A. Longobardi, A. Boselli, S. Boissier, S. Bianchi, P. Andreani, E. Sarpa, A. Nanni, M. Miville-Deschenes

Comments: 5 pages, 3 figures, accepted as letter to the editor on A&A

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

We present the first detection of diffuse dust in the intra-cluster medium of the Virgo cluster out to $\sim$0.4 virial radii, and study the radial variation of its properties on a radial scale of the virial radius. Analysing near-UV - $i$ colours for a sample of $\sim12000$ background galaxies with redshifts $0.02 < z < 0.8$, we find significant colour reddening and relate it to variation in $E(B-V)$ values. The $E(B-V)$ mean profile shows a dust component characterised by an average reddening $E(B-V)\sim0.042 \pm 0.004$ mag within 1.5 degrees ($\sim0.3\, r_{vir}$) from the cluster centre. Assuming a Large Magellanic Cloud extinction law, we derive an average visual extinction $A_{V} = 0.14\pm 0.01$ for a total dust mass, $M_{d} = 2.5\pm0.2\times10^{9}M_{\odot}$, hence a dust-to-gas mass ratio $M_{d}/M_{g} = 3.0\pm 0.3 \times 10^{-4}$. Based on the upper limits on the flux density $\mathrm{I_{250\mu m} = 0.1\, MJy sr^{-1}} $ derived from $Herschel$ data, we estimate an upper limit for the dust temperature of $T_{d} \sim 10\, K$. However, similar densities can be obtained with dust at higher temperatures with lower emissivities. The Virgo cluster has diffuse dust in its intra-cluster medium characterised by different physical properties as those characterising the Milky Way dust. The diffuse dust in Virgo is transported into the cluster space through similar phenomena (stripping) as those building up the optical intra-cluster light, and it constitutes an additional cooling agent of the cluster gas.

[9]  arXiv:2001.05518 [pdf, other]

Title: Early Ultra-Violet observations of type IIn supernovae constrain the asphericity of their circumstellar material

Authors: Maayane T. Soumagnac, Eran O. Ofek, Jingyi Liang, Avishay Gal-yam, Peter Nugent, Yi Yang, S. Bradley Cenko, Jesper Sollerman, Daniel A. Perley, Igor Andreoni, Cristina Barbarino, Kevin B. Burdge, Rachel J. Bruch, Kishalay De, Alison Dugas, Christoffer Fremling, Melissa L. Graham, Matthew J. Hankins, Nora Linn Strotjohann, Shane Moran, James D. Neill, Steve Schulze, David L. Shupe, Brigitta M. Sipocz, Kirsty Taggart, Leonardo Tartaglia, Richard Walters, Lin Yan, Yuhan Yao, Ofer Yaron, Eric C. Bellm, Chris Cannella, Richard Dekany, Dmitry A. Duev, Michael Feeney, Sara Frederick, Matthew J. Graham, Russ R. Laher, Frank J. Masci, Mansi M. Kasliwal, Marek Kowalski, Adam A. Miller, Mickael Rigault, Ben Rusholme

Comments: Submitted to ApJ. Comments are welcome

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

We present a survey of the early evolution of 12 Type IIn supernovae (SNe IIn) in the Ultra-Violet (UV) and visible light. We use this survey to constrain the geometry of the circumstellar material (CSM) surrounding SN IIn explosions, which may shed light on their progenitor diversity. In order to distinguish between aspherical and spherical circumstellar material (CSM), we estimate the blackbody radius temporal evolution of the SNe IIn of our sample, following the method introduced by Soumagnac et al. We find that higher luminosity objects tend to show evidence for aspherical CSM. Depending on whether this correlation is due to physical reasons or to some selection bias, we derive a lower limit between 35% and 66% on the fraction of SNe IIn showing evidence for aspherical CSM. This result suggests that asphericity of the CSM surrounding SNe IIn is common - consistent with data from resolved images of stars undergoing considerable mass loss. It should be taken into account for more realistic modelling of these events.

[10]  arXiv:2001.05519 [pdf, other]

Title: Super-resolution emulator of cosmological simulations using deep physical models

Authors: Doogesh Kodi Ramanah, Tom Charnock, Francisco Villaescusa-Navarro, Benjamin D. Wandelt

Comments: 10 pages, 9 figures. For submission to MNRAS

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

We present an extension of our recently developed Wasserstein optimized model to emulate accurate high-resolution features from computationally cheaper low-resolution cosmological simulations. Our deep physical modelling technique relies on restricted neural networks to perform a mapping of the distribution of the low-resolution cosmic density field to the space of the high-resolution small-scale structures. We constrain our network using a single triplet of high-resolution initial conditions and the corresponding low- and high-resolution evolved dark matter simulations from the Quijote suite of simulations. We exploit the information content of the high-resolution initial conditions as a well constructed prior distribution from which the network emulates the small-scale structures. Once fitted, our physical model yields emulated high-resolution simulations at low computational cost, while also providing some insights about how the large-scale modes affect the small-scale structure in real space.

[11]  arXiv:2001.05536 [pdf, other]

Title: VVV-WIT-01: highly obscured classical nova or protostellar collision?

Authors: P. W. Lucas, D. Minniti, A. Kamble, D. L. Kaplan, N. Cross, I. Dekany, V.D. Ivanov, R. Kurtev, R.K. Saito, L.C. Smith, M. Catelan, N. Masetti, I. Toledo, M. Hempel, M.A. Thompson, C. Contreras Peña, J. Forbrich, M. Krause, J. Dale, J. Borissova, J. Emerson

Comments: 13 pages, 7 figures. Accepted by MNRAS

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

A search of the first Data Release of the VISTA Variables in the Via Lactea (VVV) Survey discovered the exceptionally red transient VVV-WIT-01 ($H-K_s=5.2$). It peaked before March 2010, then faded by $\sim$9.5 mag over the following two years. The 1.6--22 $\mu$m spectral energy distribution in March 2010 was well fit by a highly obscured black body with $T \sim 1000$ K and $A_{K_s} \sim 6.6$ mag. The source is projected against the Infrared Dark Cloud (IRDC) SDC G331.062$-$0.294. The chance projection probability is small for any single event ($p \approx 0.01$ to 0.02) which suggests a physical association, e.g. a collision between low mass protostars. However, black body emission at $T \sim 1000$ K is common in classical novae (especially CO novae) at the infrared peak in the light curve, due to condensation of dust $\sim$30--60 days after the explosion. Radio follow up with the Australia Telescope Compact Array (ATCA) detected a fading continuum source with properties consistent with a classical nova but probably inconsistent with colliding protostars. Considering all VVV transients that could have been projected against a catalogued IRDC raises the probability of a chance association to $p=0.13$ to 0.24. After weighing several options, it appears likely that VVV-WIT-01 was a classical nova event located behind an IRDC.

[12]  arXiv:2001.05555 [pdf, other]

Title: Probing the Influence of a Tachocline in Simulated M-Dwarf Dynamos

Authors: Connor P. Bice, Juri Toomre

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

In recent years, observers have found that the fraction of M-stars demonstrating significant magnetic activity transitions sharply from roughly $10\%$ for main-sequence stars earlier (more massive) than spectral type M3.5 (0.35 M$_\odot$) to nearly $90\%$ for stars later than M3.5. The latter are typically rotating quite rapidly, suggesting differing spin-down histories. Tantalizingly, it is also later than M3.5 at which main-sequence stars become fully convective, and may no longer contain a tachocline, a layer of rotational shear revealed by helioseismology to separate the radiative zone (RZ) and convection zone (CZ). We turn here to the more massive M-stars to study the impact such a layer may have on their internal dynamics. Using the spherical 3D MHD simulation code Rayleigh, we compare the properties of convective dynamos generated within quickly rotating (1, 2, and 4 $\Omega_\odot$) M2 (0.4 M$_\odot$) stars, with the computational domain either terminating at the base of the convection zone or permitting overshoot into the underlying stable region. We find that a tachocline is not necessary for the organization of strong toroidal wreaths of magnetism in these stars, though its presence can increase the coupling of mean field amplitudes to the stellar rotation rate. Additionally, in stars that undergo periodic cycles, we find that the presence of a tachocline tends to make the cycles both longer and more regular than they would have otherwise been. Finally, we find that the tachocline helps to enhance the surface poloidal fields and organize them into larger spatial scales, both of which provide favorable conditions for more rapid angular momentum loss through a magnetized stellar wind.

[13]  arXiv:2001.05570 [pdf, other]

Title: A survey for variable young stars with small telescopes: II -- Mapping a protoplanetary disk with stable structures at 0.15 AU

Authors: Jack J. Evitts, Dirk Froebrich, Aleks Scholz, Jochen Eislöffel, Justyn Campbell-White, Will Furnell, Thomas Urtly, Roger Pickard, Klaas Wiersema, Pavol A. Dubovský, Igor Kudzej, Ramon Naves, Mario Morales Aimar, Rafael Castillo García, Tonny Vanmunster, Erik Schwendeman, Francisco C. Soldán Alfaro, Stephen Johnstone, Rafael Gonzalez Farfán, Thomas Killestein, Jesús Delgado Casal, Faustino García de la Cuesta, Dean Roberts, Ulrich Kolb, Luís Montoro, Domenico Licchelli, Alex Escartin Perez, Carlos Perelló Perez, Marc Deldem, Stephen R.L. Futcher, Tim Nelson, Shawn Dvorak, Dawid Moździerski, Nick Quinn, Krzysztof Kotysz, Katarzyna Kowalska, Przemysław Mikołajczyk, George Fleming, Mark Phillips, Tony Vale, Franky Dubois, Ludwig Logie, et al. (17 additional authors not shown)

Comments: 27 pages, 17 figures, accepted by MNRAS, full version with full appendix available at this http URL

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

The HOYS citizen science project conducts long term, multifilter, high cadence monitoring of large YSO samples with a wide variety of professional and amateur telescopes. We present the analysis of the light curve of V1490Cyg in the Pelican Nebula. We show that colour terms in the diverse photometric data can be calibrated out to achieve a median photometric accuracy of 0.02mag in broadband filters, allowing detailed investigations into a variety of variability amplitudes over timescales from hours to several years. Using GaiaDR2 we estimate the distance to the Pelican Nebula to be 870$^{+70}_{-55}$pc. V1490Cyg is a quasi-periodic dipper with a period of 31.447$\pm$0.011d. The obscuring dust has homogeneous properties, and grains larger than those typical in the ISM. Larger variability on short timescales is observed in U and R$_c-$H$\alpha$, with U-amplitudes reaching 3mag on timescales of hours, indicating the source is accreting. The H$\alpha$ equivalent width and NIR/MIR colours place V1490Cyg between CTTS/WTTS and transition disk objects. The material responsible for the dipping is located in a warped inner disk, about 0.15AU from the star. This mass reservoir can be filled and emptied on time scales shorter than the period at a rate of up to 10$^{-10}$M$_\odot$/yr, consistent with low levels of accretion in other T Tauri stars. Most likely the warp at this separation from the star is induced by a protoplanet in the inner accretion disk. However, we cannot fully rule out the possibility of an AA Tau-like warp, or occultations by the Hill sphere around a forming planet.

[14]  arXiv:2001.05587 [pdf, other]

Title: Expected performances of the Characterising Exoplanet Satellite (CHEOPS) II. The CHEOPS simulator

Authors: David Futyan, Andrea Fortier, Mathias Beck, David Ehrenreich, Anja Bekkelien, Willy Benz, Nicolas Billot, Vincent Bourrier, Christopher Broeg, Andrew Collier Cameron, Adrien Deline, Thibault Kuntzer, Monika Lendl, Didier Queloz, Reiner Rohlfs, Attila E. Simon, Francois Wildi

Comments: Accepted for publication in A&A. 16 pages, 18 figures

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

The CHaracterising ExOPlanet Satellite (CHEOPS) is a mission dedicated to the search for exoplanetary transits through high precision photometry of bright stars already known to host planets. The telescope will provide the unique capability of determining accurate radii for planets whose masses have already been measured from ground-based spectroscopic surveys. This will allow a first-order characterisation of the planets' internal structure through the determination of the bulk density, providing direct insight into their composition. The CHEOPS simulator has been developed to perform detailed simulations of the data which is to be received from the CHEOPS satellite. It generates accurately simulated images that can be used to explore design options and to test the on-ground data processing, in particular, the pipeline producing the photometric time series. It is, thus, a critical tool for estimating the photometric performance expected in flight and to guide photometric analysis. It can be used to prepare observations, consolidate the noise budget, and asses the performance of CHEOPS in realistic astrophysical fields that are difficult to reproduce in the laboratory. Images generated by CHEOPSim take account of many detailed effects, including variations of the incident signal flux and backgrounds, and detailed modelling of the satellite orbit, pointing jitter and telescope optics, as well as the CCD response, noise and readout. The simulator results presented in this paper have been used in the context of validating the data reduction processing chain, in which image time series generated by CHEOPSim were used to generate light curves for simulated planetary transits across real and simulated targets. Independent analysts were successfully able to detect the planets and measure their radii to an accuracy within the science requirements of the mission.

[15]  arXiv:2001.05597 [pdf, other]

Title: Stellar Characterization of M-dwarfs from the APOGEE Survey: A Calibrator Sample for the M-dwarf Metallicities

Authors: Diogo Souto, Katia Cunha, Verne V. Smith, C. Allende Prieto, Adam Burgasser, Kevin Covey, D. A. Garcia-Hernandez, Jon A. Holtzman, Jennifer A. Johnson, Henrik Jonsson, Suvrath Mahadevan, Steven R. Majewski, Thomas Masseron, Matthew Shetrone, Barbara Rojas-Ayala, Jennifer Sobeck, Keivan G. Stassun, Ryan Terrien, Johanna Teske, Fabio Wanderley, Olga Zamora

Comments: Accepted to ApJ, 2 tables and 11 figures

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

We present spectroscopic determinations of the effective temperatures, surface gravities and metallicities for 21 M-dwarfs observed at high-resolution (R $\sim$ 22,500) in the \textit{H}-band as part of the SDSS-IV APOGEE survey. The atmospheric parameters and metallicities are derived from spectral syntheses with 1-D LTE plane parallel MARCS models and the APOGEE atomic/molecular line list, together with up-to-date H$_{2}$O and FeH molecular line lists. Our sample range in $T_{\rm eff}$ from $\sim$ 3200 to 3800K, where eleven stars are in binary systems with a warmer (FGK) primary, while the other 10 M-dwarfs have interferometric radii in the literature. We define an $M_{K_{S}}$--Radius calibration based on our M-dwarf radii derived from the detailed analysis of APOGEE spectra and Gaia DR2 distances, as well as a mass-radius relation using the spectroscopically-derived surface gravities. A comparison of the derived radii with interferometric values from the literature finds that the spectroscopic radii are slightly offset towards smaller values, with $\Delta$ = -0.01 $\pm$ 0.02 $R{\star}$/$R_{\odot}$. In addition, the derived M-dwarf masses based upon the radii and surface gravities tend to be slightly smaller (by $\sim$5-10\%) than masses derived for M-dwarf members of eclipsing binary systems for a given stellar radius. The metallicities derived for the 11 M-dwarfs in binary systems, compared to metallicities obtained for their hotter FGK main-sequence primary stars from the literature, shows excellent agreement, with a mean difference of [Fe/H](M-dwarf - FGK primary) = +0.04 $\pm$ 0.18 dex, confirming the APOGEE metallicity scale derived here for M-dwarfs.

[16]  arXiv:2001.05600 [pdf, other]

Title: Population synthesis of helium white dwarf--red giant star mergers and the formation of lithium-rich giants and carbon stars

Authors: Xianfei Zhang, C.Simon Jeffery, Yaguang Li, Shaolan Bi

Comments: 14 pages, 19 figues, accepted to ApJ

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

The formation histories of lithium-rich and carbon-rich red giants are not yet understood. It has been proposed that the merger of a helium-core white dwarf with a red giant branch star might provide a solution. We have computed an extended grid of post-merger evolution models and combined these with predictions of binary star population synthesis. The results strongly support the proposal that the merger of a helium white dwarf with a red giant branch star can provide the progenitors of both lithium-rich red clump stars and early-R carbon stars. The distribution of post-merger models in $T_{\rm eff}$, $\log g$, $\log L$, the surface abundances of lithium and carbon, and the predicted space densities agree well with the observed distributions of these parameters for Li-rich and early-R stars in the Galaxy.

[17]  arXiv:2001.05601 [pdf, other]

Title: Revealing the Double Nucleus of NGC 4490

Authors: AL Lawrence, C. R. Kerton, Curtis Struck, Beverly J. Smith

Comments: 33 pages, 11 figures, 5 tables, Accepted for publication in the Astrophysical Journal

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

NGC 4490/85 (UGC 7651/48) or Arp 269 is well known for being one of the closest interacting/merging galactic systems. NGC 4490 has a high star formation rate (SFR) and is surrounded by an enormous HI feature stretching about 60 kpc north and south of the optically visible galaxies. Both the driver for the high SFR in NGC 4490 and the formation mechanism of the HI structure are puzzling aspects of this system. We have used mid-infrared Spitzer data to show that NGC 4490 has a double nucleus morphology. One nucleus is visible in the optical, while the other is only visible at infrared and radio wavelengths. We find the optical nucleus and the potential infrared visible nucleus have similar sizes, masses, and luminosities. Both are comparable in mass and luminosity to other nuclei found in interacting galaxy pairs and much more massive and luminous compared with typical non-nuclear star-forming complexes. We examine possible origin scenarios for the infrared feature, and conclude that it is likely that NGC 4490 is itself a merger remnant, which is now interacting with NGC 4485. This earlier encounter provides both a possible driver for extended star formation in NGC 4490, and multiple pathways for the formation of the extended HI plume.

[18]  arXiv:2001.05604 [pdf, other]

Title: ALMA band 8 observations of DLA2233+131 at z=3.150

Authors: Kazuyuki Ogura, Hideki Umehata, Yoshiaki Taniguchi, Yuichi Matsuda, Nobunari Kashikawa, Kartik Sheth, Katsuhiro Murata, Masaru Kajisawa, Masakazu A. R. Kobayashi, Takashi Murayama, Tohru Nagao

Comments: 11 pages, 4 figures, accepted to PASJ

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

We present our ALMA Band 8 observations of a damped Ly${\alpha}$ absorption (DLA) system at $z$=3.150 observed in the spectrum of the quasar Q2233+131 at $z$=3.295. The optical counterpart of this DLA has been identified and it shows a double-peaked Ly${\alpha}$ emission line. Since one possible origin of DLAs at high redshift is an outflowing gas from star-forming galaxies, DLA2233+131 provides a good laboratory to investigate the nature of high-$z$ DLAs. Motivated by this, we have carried out ALMA band 8 observations to study the [C II] line in this system. However, we do not detect any significant emission line in the observed pass bands. Instead, we have serendipitously found three submm continuum sources in the observed sky area. One appears to be the quasar Q2233+131 itself while the other two sources are newly identified submm galaxies (SMGs), called SMG1 and SMG2 in this paper. They are located at a separation of 400.7 and 800.1 from Q2233+131, respectively. Their 646 ${\mu}$m fluxes are 6.35 mJy and 6.43 mJy, respectively, being higher than that of Q2233+131, 3.62 mJy. Since these two SMGs are not detected in the optical images obtained with the Hubble Space Telescope and the Subaru Telescope, they have a very red spectral energy distribution. It is, therefore,suggested that they are high-redshift galaxies or very dusty galaxies at intermediate redshift although we cannot rule out the possibility that they are optically very faint SMG analogs at low redshift. Follow up observations will be necessary to explore the nature of this interesting region.

[19]  arXiv:2001.05612 [pdf, ps, other]

Title: Two-temperature radiative hot accretion flow around neutron stars

Authors: De-Fu Bu (SHAO), Erlin Qiao (NAOC), Xiao-Hong Yang (CQU)

Comments: 12 pages, 4 figures, accepted by ApJ

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

Numerical simulations of radiative two-temperature hot accretion flows (HAFs) around Neutron stars (NSs) are performed. We assume that all of the energy carried by the HAF around a NS will be thermalized and radiated out at the surface of the NS. The thermal photons will propagate outwards radially and cool the HAF vis Comptonization. We define $\dot m$ as the mass accretion rate at the surface of the central object in unit of Eddington accretion rate ($\dot M_{\rm Edd}=10L_{\rm Edd}/c^2$, with $L_{\rm Edd}$ and $c$ being Eddington luminosity and speed of light, respectively). When $\dot m$ is lower than $\sim 10^{-4}$, the cooling of the HAF is not important and outflows are very strong. When $\dot m > \sim 10^{-3}$, cooling becomes important and outflows are significantly weak. In the range $10^{-4} < \dot m < 10^{-3}$, the HAFs transients from a strong outflow phase to a very weak outflow phase with increase of $\dot m$. The properties of the HAF around a NS are also compared to those of the HAF around a BH. We find that with a similar $\dot m$, the dynamical properties of the HAF around a NS are quite similar as those of the HAF around a BH. However, the emitted spectrum of a HAF around a NS can be quite different from that of a HAF around a BH due to the presence of a thermal soft X-ray component coming from the surface of the NS.

[20]  arXiv:2001.05623 [pdf, ps, other]

Title: CO-Line and Radio Continuum Study of Elephant Trunks: The Pillars of Creation in M16

Authors: Yoshiaki Sofue

Comments: 15 pages, 16 figures, to appear in MNRAS

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

Molecular-line and radio continuum properties of the elephant trunks (ET, pillars of creation) in M16 are investigated by analyzing the 12CO(J=1-0), 13CO(J=1-0) and C18O(J=1-0)-line survey data with the Nobeyama 45-m telescope and the Galactic plane radio survey at 20 and 90 cm with the Very Large Array. The head clump of Pillar West I is found to be the brightest radio source in M16, showing thermal spectrum and property of a compact HII region with the nearest O5 star in NGC 6611 being the heating source. The radio pillars have cometary structure concave to the molecular trunk head, and the surface brightness distribution obeys a simple illumination law by a remote excitation source. The molecular density in the pillar head is estimated to be several $10^4$ H$_2$ cm$^{-3}$ and molecular mass $\sim 13-40 M\odot$. CO-line kinematics reveals random rotation of the clumps in the pillar tail at $\sim 1-2$ km/s, comparable to the velocity dispersion and estimated Alfven velocity. It is suggested that the random directions of velocity gradients would manifest a torsional magnetic oscillation of the clumps around the pillar axis.

[21]  arXiv:2001.05638 [pdf, ps, other]

Title: The Origins of X-ray Line Emissions in Circinus~X-1 at Very Low X-ray Flux

Authors: N.S. Schulz, T.E. Kallman, S. Heinz, P. Sell, P. Jonker, W.N. Brandt

Comments: 11 pages, 9 figures, 3 tables

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

Accretion conditions and morphologies of X-ray transients containing neutron stars are still poorly understood. Circinus X-1 is an enigmatic case where we observe X-ray flux changes covering four orders of magnitude. We observed Circinus X-1 several times at its very lowest X-ray flux using the high energy transmission grating spectrometer on board the Chandra X-ray Observatory. At a flux of 1.8$\times10^{-11}$ \ergcm we observed a single 1.6 keV blackbody spectrum. The observed continuum luminosity of 10$^{35}$ \ergsec is about two orders of magnitude too low to explain the observed photoionized luminosity suggesting a much more complex structure of the X-ray source which is partially or entirely obscured as had been previously suggested. This affects most emissions from the accretion disk including previously observed accretion disk coronal line emissions. Instead, the strongest observed photoionized lines are blueshifted by about $\sim 400$ \kms\ and we suggest that they originate in the ionized wind of a B5Ia supergaint companion supporting a previous identification. The neutron star in Cir X-1 is very young and should have a high magnetic field. At the observed luminosity the emission radius of the blackbody is small enough to be associated with the accretion hot spot as the X-ray emitting region. The small emission radius then points to a field strength below $10^{12}$ G which would be consistent with the observation of occasional type I X-ray bursts at high magnetic fields. We discuss Cir X-1 in the context of being a high-mass X-ray binary with some emphasis on a possible Be-star X-ray binary nature.

[22]  arXiv:2001.05639 [pdf, other]

Title: Aging Halos: Implications of the Magnitude Gap on Conditional Statistics of Stellar and Gas Properties of Massive Halos

Authors: Arya Farahi, Matthew Ho, Hy Trac

Comments: 14 pages, 6 Figures, 6 Tables, MNRAS

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

Cold dark matter model predicts that the large-scale structure grows hierarchically. Small dark matter halos form first. Then, they grow gradually via continuous merger and accretion. These halos host the majority of baryonic matter in the Universe in the form of hot gas and cold stellar phase. Determining how baryons are partitioned into these phases requires detailed modeling of galaxy formation and their assembly history. It is speculated that formation time of the same mass halos might be correlated with their baryonic content. To evaluate this hypothesis, we employ halos of mass above $10^{14}\,M_{\odot}$ realized by TNG300 solution of the IllustrisTNG project. Formation time is not directly observable. Hence, we rely on the magnitude gap between the brightest and the fourth brightest halo galaxy member, which is shown that traces formation time of the host halo. We compute the conditional statistics of the stellar and gas content of halos conditioned on their total mass and magnitude gap. We find a strong correlation between magnitude gap and gas mass, BCG stellar mass, and satellite galaxies stellar mass, but not the total stellar mass of halo. Conditioning on the magnitude gap can reduce the scatter about halo property--halo mass relation and has a significant impact on the conditional covariance. Reduction in the scatter can be as significant as 30%, which implies more accurate halo mass prediction. Incorporating the magnitude gap has a potential to improve cosmological constraints using halo abundance and allows us to gain insight into the baryon evolution within these systems.

[23]  arXiv:2001.05648 [pdf, other]

Title: The Study of Probability Density Function in The Presence of Self-Absorption in Molecular Clouds

Authors: Yue Hu, Ka Wai Ho, Ka Ho Yuen, A. Lazarian

Comments: 12 pages, 7 figures, 2 tables, submitted to ApJ

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

Understanding the formation of stars in molecular clouds is a central topic of modern astrophysics. However, identifying the transition region where the gravity takes over and collapse occurs remains elusive. The column density probability density functions (PDFs) of the mass density is a tool developed to study turbulence and self-gravity in molecular clouds. In this work, we study the effects of self-absorption on the intensity PDFs utilizing three synthetic emission lines of CO isotopologs 12CO, 13CO, and C18O. We find that for supersonic turbulence, the change of PDFs from the log-normal to a distribution that has a power-law part depends on the abundance of molecular species that determine its optical depth. We compute the intensity PDFs for two star-forming regions Vela C and SH2-235 and find the change of PDFs in observation agrees with our numerical results. We identify the gravitational collapsing regions on Serpens and Ophiuchus molecular clouds through the PDFs of H2 column density. We conclude that the change of CO isotopologs' PDFs is independent of self-gravity, which makes the PDFs less reliable in identifying gravitational collapsing regions using emission lines.

[24]  arXiv:2001.05653 [pdf, other]

Title: Constraints on the velocity dispersion of Dark Matter from Cosmology and new bounds on scattering from the Cosmic Dawn

Authors: Iván Rodríguez-Montoya, Vladimir Ávila-Reese, Abdel Pérez-Lorenzana, Jorge Venzor

Comments: To be published in the Astrophysical Journal. 11 pages, 5 figures

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

The observational value of the velocity dispersion, $\Delta\upsilon$, is missing in the Dark Matter (DM) puzzle. Non-zero or non-thermal DM velocities can drastically influence Large Scale Structure and the 21-cm temperature at the epoch of the Cosmic Dawn, as well as the estimation of DM physical parameters, such as the mass and the interaction couplings. To study the phenomenology of $\Delta\upsilon$ we model the evolution of DM in terms of a simplistic and generic Boltzmann-like momentum distribution. Using cosmological data from the Cosmic Microwave Background, Baryonic Acoustic Oscillations, and Red Luminous Galaxies, we constrain the DM velocity dispersion for a broad range of masses $10^{-3} eV < m_\chi < 10^9 eV$, finding $\Delta\upsilon_0 \lesssim$ 0.33 km/s (99% CL). Including the EDGES $T_{21}$-measurements, we extend our study to constrain the baryon-DM interaction in the range of DM velocities allowed by our analysis. As a consequence, we present new bounds on two electromagnetic models of DM, namely minicharged particles (MCPs) and electric dipole moment (EDM). For MCPs, the parameter region that is consistent with EDGES and independent bounds on cosmological and stellar physics is very small, pointing to the sub-eV mass regime of DM. A window in the MeV-GeV may still be compatible with these bounds for MCP models without a hidden photon. But the EDM parameter region consistent with EDGES is excluded by Big-Bang Nucleosynthesis and Collider Physics.

[25]  arXiv:2001.05660 [pdf, other]

Title: Validity of NLFFF Optimization Reconstruction

Authors: G. V. Rudenko, I. S. Dmitrienko

Comments: 15 pages, 9 figures

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

We evaluate validity of NLFFF extrapolation performed with Optimization class (OPTI) codes. While explaining inevitable for OPTI partial non-solenoidality caused by the gas pressure notable role in pressure balance at photospheric heights and by mathematical aspects related to optimization and BVP (boundary value problem), we justify elimination of the non-solenoidal component (postprocessing) from the OPTI result obtained. In essence, postprocessing converts the entire non-solenoidal part into a solenoidal force part, which possibly reflects factual deviation of magnetic field from its force-free pproximation on the photosphere and in the solar corona. Two forms of postprocessing have been analyzed in this paper.Postprocessing I eliminates the non-solenoidal component without changing transverse field at the measurement level, and Postprocessing II leaves the field normal component unchanged. Extrapolation, postprocessing, and then comparison of metric and energy characteristics are performed over AR 11158 active region for a small fragment of its evolution containing the February X-class flare.Our version of OPTI code showed that free energy decreased by $\sim 10^{32}$ erg within 1 hour, which corresponds to theoretical estimations of the flare-caused magnetic energy loss. This result differs significantly from the one in Sun et al. (2012).Therefore, we also comment on some features of our OPTI code implementation, which may cause significant differences between our results and those obtained using the Wiegelmann (2004) version of OPTI code in study by Sun et al. (2012).

[26]  arXiv:2001.05677 [pdf, other]

Title: Modeling the IRIS Lines During a Flare. I. The Blue-Wing Enhancement in the Mg II k Line

Authors: Jie Hong, Ying Li, M. D. Ding, Yu-Hao Zhou

Comments: 19 pages, 11 figures, accepted for publication in ApJ

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

The IRIS Mg II k line serves as a very good tool to diagnose the heating processes in solar flares. Recent studies have shown that apart from the usual red asymmetries which are interpreted as the result of condensation downflows, this line could also show a blue-wing enhancement. To investigate how such a blue asymmetry is formed, we perform a grid of radiative hydrodynamic simulations and calculate the corresponding line profiles. We find that such a spectral feature is likely to originate from the upward plasma motion in the upper chromosphere. However, the formation region that is responsible for the blue-wing enhancement could be located in an evaporation region, in an upward moving blob, and even an upward moving condensation region. We discuss how the electron beam parameters affect these different dynamics of the atmosphere.

[27]  arXiv:2001.05679 [pdf, other]

Title: The physical properties of S0 galaxy PGC 26218: the origin of starburst and star formation

Authors: Xue Ge, Qiu-Sheng Gu, Rubén García-Benito, Meng-Yuan Xiao, Zong-Nan Li

Comments: accepted for publication in ApJ, 16 page, 12 figures

Journal-ref: Astrophysical Journal, 2020

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

We present 2D-spectroscopic observations from Centro Astron\'omico Hispano Alem\'an (CAHA) 3.5 m telescope and the millimetre observation from NOrthern Extended Millimeter Array (NOEMA) of the nearby S0 galaxy PGC 26218, which shows central star-formation activity and post-starburst outside in the disk. We estimate the star formation rate (SFR = $0.28\pm0.01$ $M_{\odot} \rm yr^{-1}$) and molecular gas mass ($\rm log\ $$M_{\rm H_{2}}=7.60\pm0.15\ M_{\odot}$) of PGC 26218 based on the extinction-corrected H$\alpha$ emission line and the CO-$\rm H_{2}$ conversion factor ($\alpha_{\rm CO}$) of the Milky Way, respectively. We find that PGC 26218 follows the star forming main sequence (SFMS) and the Kennicutt-Schmidt law. Comparing the kinematics of CO($J$=1-0), stars and H$\alpha$, we find that the rotational axis of CO($J$=1-0) is 45$^{\circ}$ different from that of H$\alpha$. In addition, the profile of the CO($J$=1-0) emission line shows asymmetry and has an inflow component of $\sim$ 46 $\rm km\ s^{-1}$. With the decomposition of the optical image, we confirm that PGC 26218 shows multiple nuclear structures. The projected offset between the most luminous optical center and the center of CO($J$=1-0) is $5.2\arcsec$ ($\sim$ 0.6 kpc) and the latter overlaps with one of the optical cores. These results support that PGC 26218 may have experienced a gas-rich minor merger, extending its star formation and locating it in the SFMS.

[28]  arXiv:2001.05683 [pdf, other]

Title: First Results from MFOSC-P : Low Resolution Optical Spectroscopy of a Sample of M dwarfs within 100 parsecs

Authors: A. S. Rajpurohit, Vipin Kumar, Mudit K. Srivastava, F. Allard, D. Homeier, Vaibhav Dixit, Ankita Patel

Comments: Accepted for Publication in MNRAS

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

Mt. Abu Faint Object Spectrograph and Camera (MFOSC-P) is an in-house developed instrument for Physical Research Laboratory (PRL) 1.2m telescope at Mt. Abu India, commissioned in February 2019. Here we present the first science results derived from the low resolution spectroscopy program of a sample of M Dwarfs carried out during the commissioning run of MFOSC-P between February-June 2019. M dwarfs carry great significance for exoplanets searches in habitable zone and are among the promising candidates for the observatory's several ongoing observational campaigns. Determination of their accurate atmospheric properties and fundamental parameters is essential to constrain both their atmospheric and evolutionary models. In this study, we provide a low resolution (R$\sim$500) spectroscopic catalogue of 80 bright M dwarfs (J$<$10) and classify them using their optical spectra. We have also performed the spectral synthesis and $\chi^2$ minimisation techniques to determine their fundamental parameters viz. effective temperature and surface gravity by comparing the observed spectra with the most recent BT-Settl synthetic spectra. Spectral type of M dwarfs in our sample ranges from M0 to M5. The derived effective temperature and surface gravity are ranging from 4000 K to 3000 K and 4.5 to 5.5 dex, respectively. In most of the cases, the derived spectral types are in good agreement with previously assigned photometric classification.

[29]  arXiv:2001.05702 [pdf, other]

Title: The statistics of peaks of weakly non-Gaussian random fields: Effects of bispectrum in two- and three-dimensions

Authors: Takahiko Matsubara

Comments: 19 pages, 5 figures

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

Analytic expressions for the statistics of peaks of random fields with weak non-Gaussianity are provided. Specifically, the abundance and spatial correlation of peaks are represented by formulas which can be evaluated only by virtually one-dimensional integrals. We assume the non-Gaussianity is weak enough such that it is represented by linear terms of the bispectrum. The formulas are formally given in $N$-dimensional space, and explicitly given in the case of $N=1,2,3$. Some examples of peak statistics in cosmological fields are calculated for the cosmic density field and weak lensing field, assuming the weak non-Gaussianity is induced by gravity. The formulas of this paper would find a fit in many applications to statistical analyses of cosmological fields.

[30]  arXiv:2001.05738 [pdf, other]

Title: Stellar age gradients and inside-out star formation quenching in galaxy bulges

Authors: Iris Breda, Polychronis Papaderos, Jean Michel Gomes, José Manuel Vílchez, Bodo L. Ziegler, Michaela Hirschmann, Leandro S.M. Cardoso, Patricio Lagos, Fernando Buitrago

Comments: 7 pages, 4 figures

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

Radial age gradients hold the cumulative record of the multitude of physical processes driving the build-up of stellar populations and the ensuing star formation (SF) quenching process in galaxy bulges, therefore potentially sensitive discriminators between competing theoretical concepts on bulge formation and evolution. Based on spectral modeling of integral field spectroscopy data from the CALIFA survey, we derive mass- and light-weighted stellar age gradients ($\nabla$(t,B)L,M) within the photometrically determined bulge radius (RB) of a representative sample of local face-on late-type galaxies that span 2.6 dex in stellar mass. Our analysis documents a trend for decreasing $\nabla$(t,B)L,M with increasing M,T, with high-mass bulges predominantly showing negative age gradients and vice versa. The inversion from positive to negative $\nabla$(t,B)L,M occurs at logM,T ~ 10, which roughly coincides with the transition from lower-mass bulges whose gas excitation is powered by SF to bulges classified as Composite, LINER or Seyfert. We discuss two limiting cases for the origin of radial age gradients in massive LTG bulges. The first assumes that the stellar age in the bulge is initially spatially uniform, thus the observed age gradients arise from an inside-out SF quenching (ioSFQ) front that is radially expanding with a mean velocity vq. In this case, the age gradients translate into a slow ioSFQ that lasts until z~2, suggesting mild negative feedback by SF or an AGN. If negative age gradients in massive bulges are not due to ioSFQ but primarily due to their inside-out formation process, then the standard hypothesis of quasi-monolithic bulge formation has to be discarded in favor of a scenario that involves gradual buildup of stellar mass over 2-3 Gyr through, e.g., inside-out SF and inward migration of SF clumps from the disk. In this case, rapid AGN-driven ioSFQ cannot be ruled out.

[31]  arXiv:2001.05746 [pdf, other]

Title: Ultra-deep imaging with amateur telescopes

Authors: David Martinez-Delgado

Comments: Invited Review at the IAU Symposium 355: "The Realm of the Low Surface Brightness Universe". To appear in the Proceedings of IAU Symposium No. 355 "The Realm of the Low-Surface-Brightness Universe", 2020, Eds. D. Valls-Gabaud, I. Trujillo & S. Okamoto, 20 pages, 13 figures

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

Amateur small equipment has demonstrated to be competitive tools to obtain ultra-deep imaging of the outskirts of nearby massive galaxies and to survey vast areas of the sky with unprecedented depth. Over the last decade, amateur data have revealed, in many cases for the first time, an assortment of large-scale tidal structures around nearby massive galaxies and have detected hitherto unknown low surface brightness systems in the local Universe that were not detected so far by means of resolved stellar populations or HI surveys. In the Local Group, low-resolution deep images of the Magellanic Clouds with telephoto lenses have found some shell-like features, interpreted as imprints of a recent LMC-SMC interaction. In this review, I discuss these highlights and other important results obtained so far in this new type of collaboration between high-class astrophotographers and professional astronomers in the research topic of galaxy formation and evolution.

[32]  arXiv:2001.05748 [pdf, ps, other]

Title: Spinning and color properties of the active asteroid (6478) Gault

Authors: Albino Carbognani, Alberto Buzzoni

Comments: 8 pages, 12 figures, submitted to Mon. Not. R. Astron. Soc

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

We report on accurate $BVR_{c}$ observations of (6478) Gault, a 5-6 km diameter inner main-belt asteroid in the Phocaea family, notable for its sporadic, comet-like ejection of dust. This curious behavior has been mainly interpreted as reconfigurations after YORP spin-up, although merging of a contact binary system cannot be fully excluded. We collected optical observations along the 2019 March-April period, at orbital phase angles between $12^{\circ}-21^{\circ}$, to search for direct evidence of asteroid quick spinning rotation. A prevailing period value of $3.34 \pm 0.02$ hours is supported by our and other photometric observations. In the YORP spin-up hypothesis, this period points to a bulk density $\rho \approx 1$ $\textrm{g}/\textrm{cm}^3$. The mean colors are $B-V = +0.82_{\pm 0.3}$, $V-R_{c} = +0.28_{\pm 0.06}$ and $B-R_{c} = +1.11_{\pm 0.4}$, but we have observed a strong bluer color during the April session, with about $\Delta (B-V) \sim 0.35 \pm 0.09$~mag. This color change can be due to asteroid rotation and support the hypothesis that there is a bluer surface under the Gault's dust, as indicated by spectroscopic observations made on 2019 March 31 and April 8 by Marsset et al. (2019).

[33]  arXiv:2001.05753 [pdf, other]

Title: Magnetic Fields Studies in the Next Decade: EAO Submillimetre Futures White Paper Series, 2019

Authors: Ray S. Furuya, Kate Pattle, Simon Coudé, Tao-Chung Ching, Steve Mairs, Sarah Sadavoy, Peter Scicluna, Archana Soam, Chakali Eswaraiah, Samar Safi-Harb

Comments: 17 pages, 5 figures; Part of the 2019 EAO Submillimetre Futures Paper Series, this https URL

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

Magnetic fields are ubiquitous in our Universe, but remain poorly understood in many branches of astrophysics. A key tool for inferring astrophysical magnetic field properties is dust emission polarimetry. The James Clerk Maxwell Telescope (JCMT) is planning a new 850$\mu$m camera consisting of an array of 7272 paired Microwave Kinetic Inductance Detectors (MKIDs), which will inherently acquire linear polarization information. The camera will allow wide-area polarization mapping of dust emission at 14$^{\prime\prime}$-resolution, allowing magnetic field properties to be studied in a wide range of environments, including all stages of the star formation process, Asymptotic Giant Branch stellar envelopes and planetary nebula, external galaxies including starburst galaxies and analogues for the Milky Way, and the environments of active galactic nuclei (AGN). Time domain studies of AGN and protostellar polarization variability will also become practicable. Studies of the polarization properties of the interstellar medium will also allow detailed investigation of dust grain properties and physics. These investigations would benefit from a potential future upgrade adding 450$\mu$m capability to the camera, which would allow inference of spectral indices for polarized dust emission in a range of environments. The enhanced mapping speed and polarization capabilities of the new camera will transform the JCMT into a true submillimetre polarization survey instrument, offering the potential to revolutionize our understanding of magnetic fields in the cold Universe.

[34]  arXiv:2001.05770 [pdf, other]

Title: Direct measurement of the [CI] luminosity to molecular gas mass conversion factor in high-redshift star-forming galaxies

Authors: Kasper E. Heintz, Darach Watson

Comments: 8 pages, 4 figures, 1 table. Abstract abridged. Accepted for publication in ApJL

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

The amount of cold, molecular gas in high-redshift galaxies is typically inferred from proxies of molecular hydrogen (H$_2$), such as carbon monoxide (CO) or neutral atomic carbon ([CI]) and molecular gas mass conversion factors. The use of these proxies, however, relies on modeling and observations that have not been directly measured outside the local universe. Here, we use recent samples of high-redshift gamma-ray burst (GRB) and quasar molecular gas absorbers to determine this conversion factor $\alpha_{\rm [CI]}$ from the column density of H$_2$, which gives us the mass per unit column, and the [CI]($J=1$) column density, which provides the luminosity per unit column. This technique allows us to make direct measurements of the relative abundances in high-redshift absorption-selected galaxies. Our sample spans redshifts of z=1.9-3.4 and covers two orders of magnitude in gas-phase metallicity. We find that $\alpha_{\rm [CI]}$ scales linearly with the metallicity: $\log \alpha_{\rm [CI]} = -1.13\times \log(Z/Z_{\odot}) + 1.33$, with a scatter of $\sigma_{\alpha_{\rm [CI]}} = 0.2$ dex. Using a sample of emission-selected galaxies at z~0-5, with both [CI] and CO line detections, we apply the $\alpha_{\rm [CI]}$ conversion to derive independent estimates of the molecular gas mass and $\alpha_{\rm CO}$. We find a remarkable agreement between the molecular gas masses inferred from the absorption-derived $\alpha_{\rm [CI]}$ compared to typical $\alpha_{\rm CO}$-based estimates, and an inferred metallicity evolution of $\alpha_{\rm CO}$ that is consistent with $\alpha_{\rm [CI]}$ and previous estimates from the literature. These results thus support the use of the absorption-derived $\alpha_{\rm [CI]}$ conversion factor for emission-selected star-forming galaxies and demonstrate that both methods probe the same universal properties of molecular gas in the local and high-redshift universe.

[35]  arXiv:2001.05776 [pdf, other]

Title: Environmental processing in cluster core galaxies at z=1.7

Authors: G. Castignani, F. Combes, P. Salomé

Comments: 6 pages, 3 figures, submitted to A&A Letters

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

Brightest cluster galaxies (BCG) are today passive and very massive galaxies at the center of their clusters, still accreting mass through swallowing companions, and gas from cooling flows. However their formation history is not well known. We report CO(4$\rightarrow$3) and continuum map observations of the SpARCS1049+56 BCG at $z=1.709$, one of the most distant known BCGs. Our observations yield $M_{{\rm H}_2}<1.1\times10^{10}M_\odot$ for the BCG, while we detect in CO(4$\rightarrow$3) two gas-rich companions at the north-east and south-east of the BCG, within 20 kpc, with a total $L^\prime_{\rm CO(4\rightarrow3)}=(3.2\pm0.5)\times10^{10}$ K km s$^{-1}$ pc$^2$. The northern companion is associated with a pair of merging cluster galaxies, while the { southern one} shows a southern tail in CO(4$\rightarrow$3), detected also in continuum, and we suggest it to be the most distant jellyfish galaxy, for which ram pressure stripping is effectively able to strip off its dense molecular gas. This study probes the presence of rare gas-rich systems in the very central region of a distant cluster core, which will potentially merge into the BCG itself. We may thus be seeing the reversal of the star formation vs. density relation at play in the distant universe. This is the first time the assembly of high-$z$ progenitors of our local BCGs can be studied in such a great detail.

[36]  arXiv:2001.05790 [pdf, ps, other]

Title: Unveiling Vela -- Variability of Interstellar Lines in the Direction of the Vela Supernova Remnant III. Na D and Ca II K

Authors: N.Kameswara Rao, David L. Lambert, Arumalla B.S Reddy, Ranjan Gupta, S. Muneer, Baba Varghese, Harinder P. Singh

Comments: 24 pages, 18 figures, Accepted for publication in Monthly Notices of the Royal Astronomical Society Main Journal

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

High-resolution optical spectra were obtained in 2017-2019 with The Southern African Large Telescope of fifteen stars in the direction of the Vela supernova remnant. Interstellar Ca ii H and K and Na i D lines are discussed in this paper. In particular, the line profiles are compared with profiles at a comparable spectral resolution obtained in 1993-1996 by Cha & Sembach. Ten of the lines of sight show changes to one or more of the components in that line of sight. Changes include small changes (1-2 km/s) in radial velocity and/or increases/decreases in equivalent width over the two decades between the periods of observation. Changes are more obvious in the Ca K line than in the Na D lines. These changes are attributed to gas disturbed by interactions between the supernova ejecta and the surrounding interstellar medium. A representative timescale may be 20-50 years. Small-scale variations in line profiles across the face of the remnant suggest, as previously remarked, that a linear scale for interactions is a small fraction of the 40 pc size of the present remnant.

[37]  arXiv:2001.05808 [pdf, other]

Title: Vertical gas accretion impacts the carbon-to-oxygen ratio of gas giant atmospheres

Authors: Alex J. Cridland, Arthur D. Bosman, Ewine F. van Dishoeck

Comments: Accepted for publication in A&A

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

Recent theoretical, numerical, and observational work have suggested that when a growing planet opens a gap in its disk the flow of gas into the gap is dominated by gas falling vertically from a height of at least one gas scale height. Our primary objective is to include, for the first time, the chemical impact that accreting gas above the midplane will have on the resulting C/O. We compute the accretion of gas onto planetary cores beginning at different disk radii and track the chemical composition of the gas and small icy grains to predict the resulting carbon-to-oxygen ratio (C/O) in their atmospheres. In our model, all of the planets which began their evolution inward of 60 AU open a gap in the gas disk, and hence are chemically affected by the vertically accreting gas. Two important conclusions follow from this vertical flow: (1) more oxygen rich icy dust grains become available for accretion onto the planetary atmosphere. (2) The chemical composition of the gas dominates the final C/O of planets in the inner ($<$ 20 AU) part of the disk. This implies that with the launch of the James Webb Space Telescope we can trace the disk material that sets the chemical composition of exoplanetary atmospheres.

[38]  arXiv:2001.05822 [pdf, ps, other]

Title: Solar System objects observed with TESS -- First data release: bright main-belt and Trojan asteroids from the Southern Survey

Authors: András Pál (1,2,3), Róbert Szakáts (1), Csaba Kiss (1), Attila Bódi (1,4), Zsófia Bognár (1,4), Csilla Kalup (2,1), László L. Kiss (1), Gábor Marton (1), László Molnár (1,4), Emese Plachy (1,4), Krisztián Sárneczky (1), Gyula M. Szabó (5,6), Róbert Szabó (1,4) ((1) Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, Budapest, Hungary, (2) Eötvös Loránd University, Budapest, Hungary, (3) MIT Kavli Institute for Astrophysics and Space Research, Cambridge, MA, USA, (4) MTA CSFK Lendület Near-Field Cosmology Research Group, (5) ELTE Eötvös Loránd University, Gothard Astrophysical Observatory, Szombathely, Hungary, (6) MTA-ELTE Exoplanet Research Group, Szombathely, Hungary)

Comments: ApJS, in press. Data are available from this https URL (6.36G, in total)

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

Compared with previous space-borne surveys, the Transiting Exoplanet Survey Satellite (TESS) provides a unique and new approach to observe Solar System objects. While its primary mission avoids the vicinity of the ecliptic plane by approximately six degrees, the scale height of the Solar System debris disk is large enough to place various small body populations in the field-of-view. In this paper we present the first data release of photometric analysis of TESS observations of small Solar System Bodies, focusing on the bright end of the observed main-belt asteroid and Jovian Trojan populations. This data release, named TSSYS-DR1, contains 9912 light curves obtained and extracted in a homogeneous manner, and triples the number of bodies with unambiguous fundamental rotation characteristics, namely where accurate periods and amplitudes are both reported. Our catalogue clearly shows that the number of bodies with long rotation periods are definitely underestimated by all previous ground-based surveys, by at least an order of magnitude.

[39]  arXiv:2001.05874 [pdf, ps, other]

Title: Can the quasi-molecular mechanism of recombination decrease the Hubble tension?

Authors: Revaz Beradze, Merab Gogberashvili

Comments: 6 pages, no figures

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

In the recently suggested non-standard - quasi-molecular mechanism of recombination, the presence of neighboring proton increases the ionization energy of hydrogen and decreases the final recombination rate. We note that both these two effects can lead to the larger value of the present expansion rate of the universe obtained using CMB data and standard cosmological model, and thus are able to reduce or resolve the Hubble tension problem.

[40]  arXiv:2001.05879 [pdf, ps, other]

Title: Long-term Periodicities in North-South Asymmetry of Solar Activity and Alignments of the Giant Planets

Authors: J. Javaraiah

Comments: 14 pages, 7 figures. to be published in Solar Physics

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

The existence of ~12-year and ~51-year periodicities in the north-south asymmetry of solar activity is well known. However, the origin of these as well as the well-known relatively short periodicities in the north-south asymmetry is not yet clear. Here we have analyzed the combined daily data of sunspot groups reported in Greenwich Photoheliographic Results (GPR) and Debrecen Photoheligraphic Data (DPD) during the period 1874-2017 and the data of the orbital positions (ecliptic longitudes) of the giant planets in ten-day intervals during the period 1600-2099. Our analysis suggests that ~12-year and ~51-year periodicities in the north-south asymmetry of solar activity are the manifestations of the differences in the strengths of ~11-year and ~51-year periodicities of activity in the northern- and southern-hemispheres. During the period 1874-2017 the Morlet wavelet power spectra of the north-south asymmetry of sunspot-group area and the mean absolute difference of the orbital positions of the giant planets are found to be similar. Particularly, there is a suggestion that the ~12-year and ~51-year periodicities in the north-south asymmetry of sunspot-group area occurred during approximately the same times as the corresponding periodicities in the mean absolute difference of the orbital positions of the giant planets. Therefore, we suggest that there could be influence of some specific configurations of the giant planets in the origin of the ~12-year and ~50-year periodicities of the north-south asymmetry of solar activity.

[41]  arXiv:2001.05881 [pdf, other]

Title: Towards precise and accurate Cepheid chemical abundances for 1$\%$ $\mbox{H}_0$ measurement: temperature determination

Authors: Sara Mancino, Martino Romaniello, Richard I. Anderson, Rolf-Peter Kudritzki

Comments: 5 pages, 4 figures, to appear in RRL/CEP2019 conference proceedings

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

One of the outstanding problems in modern physics is the origin is of accelerated expansion of the universe. High-precision determinations of the Hubble parameter $\mbox{H}_0$ at different redshifts provide direct insight into the Universe expansion: equation of state of the Dark Energy, geometry and curvature of space, sum of neutrino masses and isotropy of the Universe. We investigate the effect of chemical composition on the classical distance ladder based on Cepheids stars and Supernovae type Ia. Cepheids belonging to Magellanic Clouds represent a natural anchor for the ladder, due to their proximity and the very well known geometric distance. Accordingly, the LACES collaboration collected the largest spectroscopic sample of MCs Cepheids, containing more than 300 stars and more than 1200 medium-high resolution spectra. Abundance measurements, performed by equivalent width and curve of growth analysis, have been tested on a wide grid of synthetic spectra to quantify the systematic arising from this procedure. We focus on the errors arising from temperature measurements, using the Line Depth Ratio method. We find that in order to not bias the final results many aspects (e.g. degeneracy of the atmospheric parameters, instrumental set up etc.) should be explicitly taken into account. In particular, there is a not negligible metallicity dependence.

[42]  arXiv:2001.05891 [pdf, ps, other]

Title: International observational campaign of the 2014 eclipse of EE Cep

Authors: D. Pieńkowski, C. Gałan, T. Tomov, K. Gazeas, P. Wychudzki, M. Mikołajewski, D. Kubicki, B. Staels, S. Zoła, P. Pakońska, B. Dȩbski, T. Kundera, W. Ogłoza, M. Dróżdż, A. Baran, M. Winiarski, M. Siwak, D. Dimitrov, D. Kjurkchieva, D. Marchev, A. Armiński, I. Miller, Z. Kołaczkowski, D. Moździerski, E. Zahajkiewicz, P. Bruś, A. Pigulski, T. Smela, E. Conseil, D. Boyd, G. J. Conidis, I. Plauchu-Frayn, T. A. Heras, E. Kardasis, M. Biskupski, R. Kneip, L. Hambálek, T. Pribulla, E. Kundra, J. Nedoroščik, J. Lopatovský, Z. Garai, D. Rodriguez, T. Kamiński, F. Dubois, L. Logie, A. Capetillo Blanco, P. Kankiewicz, E. Świerczyński, M. Martignoni, I. Sergey, J. Kare Trandem Qvam, et al. (17 additional authors not shown)

Comments: 10 pages, 13 figures, 29 tables in appendix, submited to Astronomy & Astrophysics

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

Context. EE Cep is one of few eclipsing binary systems with a dark, dusty disk around an invisible object similar to {\epsilon} Aur. The system is characterized by grey and asymmetric eclipses every 5.6 yr, with a significant variation in their photometric depth, ranging from ~ 0 m .5 to ~ 2 m .0. Aims. The main aim of the observational campaign of the EE Cep eclipse in 2014 was to test the model of disk precession (Galan et al. 2012). We expected that this eclipse would be one of the deepest with a depth of ~ 2 m .0. Methods. We collected multicolor observations from almost 30 instruments located in Europe and North America. This photometric data covers 243 nights during and around the eclipse. We also analyse the low- and high-resolution spectra from several instruments. Results. The eclipse was shallow with a depth of 0 m .71 in V-band. The multicolor photometry illustrates small color changes during the eclipse with a total amplitude of order ~ +0 m . 15 in B-I color index. The linear ephemeris for this system is updated by including new times of minima, measured from the three most recent eclipses at epochs E = 9, 10 and 11. New spectroscopic observations were acquired, covering orbital phases around the eclipse, which were not observed in the past and increased the data sample, filling some gaps and giving a better insight into the evolution of the H {\alpha} and NaI spectral line profiles during the primary eclipse. Conclusions. The eclipse of EE Cep in 2014 was shallower than expected 0 m .71 instead of ~ 2 m . 0. This means that our model of disk precession needs revision.

[43]  arXiv:2001.05898 [pdf, ps, other]

Title: NuSTAR and Parkes observations of the transitional millisecond pulsar binary XSS J12270-4859 in the rotation-powered state

Authors: D. de Martino, A. Papitto, M. Burgay, A. Possenti, F. Coti Zelati, N. Rea, D.F. Torres, T.M. Belloni

Comments: 15 pages, 12 figures, 5 tables - Accepted for publication in MNRAS Main Journal

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

We report on the first NuSTAR observation of the transitional millisecond pulsar binary XSS J12270-4859 during its current rotation-powered state, complemented with a 2.5yr-long radio monitoring at Parkes telescope and archival XMM-Newton and Swift X-ray and optical data. The radio pulsar is mainly detected at 1.4GHz displaying eclipses over about 40% of the 6.91h orbital cycle. We derive a new updated radio ephemeris to study the 3-79keV light curve that displays a significant orbital modulation with fractional amplitude of 28+/-3%, a structured maximum centred at the inferior conjunction of the pulsar and no cycle-to-cycle or low-high-flaring mode variabilities. The average X-ray spectrum, extending up to about 70keV without a spectral break, is well described by a simple power-law with photon index Gamma = 1.17+/-0.08 giving a 3-79keV luminosity of 7.6(-0.8;+3.8)x10**32 erg/s, for a distance of 1.37(-0.15;+0.69)kpc. Energy resolved orbital light curves reveal that the modulation is not energy dependent from 3keV to 25keV and is undetected with an upper limit of about 10% above 25keV. Comparison with previous X-ray XMM-Newton observations in common energy ranges confirms that the modulation amplitudes vary on timescales of a few months, indicative of a non-stationary contribution of the intrabinary shock formed by the colliding winds of the pulsar and the companion. A more detailed inspection of energy resolved modulations than previously reported gives hints of a mild softening at superior conjunction of the pulsar below 3keV, likely due to the contribution of the thermal emission from the neutron star. The intrabinary shock emission, if extending into the MeV range, would be energetically capable alone to irradiate the donor star.

[44]  arXiv:2001.05899 [pdf, other]

Title: 3D maps of the Magellanic Clouds using Classical Cepheids

Authors: Abigail H. Chown, Victoria Scowcroft

Comments: 6 pages, 3 figures, to be published in ASP Conference Series: "RR Lyrae/Cepheid 2019: Frontiers of Classical Pulsators: Theory and Observations"

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

Variable stars have been used for over one hundred years as probes for determining astronomical distances; these distances can be used to map the three-dimensional (3D) structure of nearby galaxies. Exploiting the effect that moving to the mid-infrared has on Cepheid magnitudes and light curves, we can now map our nearest galaxies in 3D at fidelities never before achievable. Combining data from the OGLE-IV catalogue with mid-infrared photometry from the Spitzer Space Telescope, around 5000 fundamental mode Cepheids are being used to trace the 3D structure of the Magellanic Clouds. An automated photometry pipeline has been developed to obtain precise mean magnitudes and light curves for Cepheids in the Magellanic System, which in turn produces distance measurements for individual Cepheids accurate to 5%. The resulting detailed maps are being used to probe the geometric and chemical structure of the Magellanic Clouds, as well as their interaction and dynamical histories. Initial results from this project are discussed and the future inclusion of RR Lyrae stars to trace the old stellar population of the system is described.

[45]  arXiv:2001.05925 [pdf, other]

Title: Coronal Photopolarimetry with the LASCO-C2 Coronagraph over 24 Years [1996-2019] -- Application to the K/F Separation and to the Determination of the Electron Density

Authors: Philippe Lamy (1), Antoine Llebaria (2), Brice Boclet (2), Hugo Gilardy (1), Michael Burtin (2 and 3), Olivier Floyd (1) ((1) Laboratoire Atmosphères, Milieux et Observations Spatiales, (2) Laboratoire d'Astrophysique de Marseille, (3) Vostok)

Comments: 72 pages, 51 figures

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

We present an in-depth characterization of the polarimetric channel of the Large-Angle Spectrometric COronagraph LASCO-C2 onboard the Solar and Heliospheric Observatory (SoHO). The polarimetric analysis of the white-light images makes use of polarized sequences composed of three images obtained though three polarizers oriented at +60{\deg}, 0{\deg} and -60{\deg}, complemented by a neighboring unpolarized image, and relies on the formalism of Mueller. The Mueller matrix characterizing the C2 instrument was obtained through extensive ground-based calibrations of the optical components and global laboratory tests. Additional critical corrections were derived from in-flight tests relying prominently on roll sequences and on consistency criteria, mainly the tangential direction of polarization. Our final results encompass the characterization of the polarization of the white-light corona, of its polarized radiance, of the two-dimensional electron density, and of the K-corona over two solar cycles. They are in excellent agreement with measurements obtained at several solar eclipses except for slight discrepancies affecting the innermost part of the C2 field-of-view, probably resulting from an imperfect removal of the bright diffraction fringe surrounding the occulter.

[46]  arXiv:2001.05926 [pdf, other]

Title: Spectral evidence of an accretion disk in wind-fed X-ray pulsar Vela X-1 during an unusual spin-up period

Authors: Zhenxuan Liao, Jiren Liu, Xueying Zheng, Lijun Gou

Comments: 8 pages, 6 figures, 2 tables, accepted for publication in MNRAS

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

In classical supergiant X-ray binaries (SgXBs), the Bondi-Hoyle-Lyttleton wind accretion was usually assumed, and the angular momentum transport to the accretors is inefficient. The observed spin-up/spin-down behavior of the neutron star in SgXBs is not well understood. In this paper, we report an extended low state of Vela X-1 (at orbital phases 0.16-0.2), lasting for at least 30 ks, observed with Chandra during the onset of an unusual spin-up period. During this low state, the continuum fluxes dropped by a factor of 10 compared to the preceding flare period, and the continuum pulsation almost disappeared. Meanwhile, the Fe K$\alpha$ fluxes of the low state were similar to the preceding flare period, leading to an Fe K$\alpha$ equivalent width (EW) of 0.6 keV, as high as the Fe K$\alpha$ EW during the eclipse phase of Vela X-1. Both the pulsation cessation and the high Fe K$\alpha$ EW indicate an axisymmetric structure with a column density larger than $10^{24}\rm cm^{-2}$ on a spatial scale of the accretion radius of Vela X-1. These phenomena are consistent with the existence of an accretion disk that leads to the following spin-up of Vela X-1. It indicates that disk accretion, although not always, does occur in classical wind-fed SgXBs.

[47]  arXiv:2001.05930 [pdf, other]

Title: Primordial Gravitational Waves from Galaxy Intrinsic Alignments

Authors: Matteo Biagetti, Giorgio Orlando

Comments: 27 pages, 6 figures, code available at this https URL

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

Galaxy shapes have been observed to align with external tidal fields generated by the large-scale structures of the Universe. While the main source for these tidal fields is provided by long-wavelength density perturbations, tensor perturbations also contribute with a non-vanishing amplitude at linear order. We show that parity-breaking gravitational waves produced during inflation leave a distinctive imprint in the galaxy shape power spectrum which is not hampered by any scalar-induced tidal field. We also show that a certain class of tensor non-Gaussianities produced during inflation can leave a signature in the density-weighted galaxy shape power spectrum. We estimate the possibility of observing such imprints in future galaxy surveys.

[48]  arXiv:2001.05942 [pdf, other]

Title: A public HARPS radial velocity database corrected for systematic errors

Authors: Trifon Trifonov, Lev Tal-Or, Mathias Zechmeister, Adrian Kaminski, Shay Zucker, Tsevi Mazeh

Comments: 16 pages, 17 figures, 4 tables, Accepted for publication in A&A

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

Context. The HARPS spectrograph provides state-of-the-art stellar radial velocity (RV) measurements with a precision down to 1 m/s. The spectra are extracted with a dedicated data-reduction software (DRS) and the RVs are computed by CCF with a numerical mask. Aims. The aim of this study is three-fold: (i) Create easy access to the public HARPS RV data set. (ii) Apply the new public SERVAL pipeline to the spectra, and produce a more precise RV data set. (iii) Check whether the precision of the RVs can be further improved by correcting for small nightly systematic effects. Methods. For each star observed with HARPS, we downloaded the publicly available spectra from the ESO archive and recomputed the RVs with SERVAL. We then computed nightly zero points (NZPs) by averaging the RVs of quiet stars. Results. Analysing the RVs of the most RV-quiet stars, whose RV scatter is < 5 m/s, we find that SERVAL RVs are on average more precise than DRS RVs by a few percent. We find three significant systematic effects, whose magnitude is independent of the software used for the RV derivation: (i) stochastic variations with a magnitude of 1 m/s; (ii) long-term variations, with a magnitude of 1 m/s and a typical timescale of a few weeks; and (iii) 20-30 NZPs significantly deviating by a few m/s. In addition, we find small (< 1 m/s) but significant intra-night drifts in DRS RVs before the 2015 intervention, and in SERVAL RVs after it. We confirm that the fibre exchange in 2015 caused a discontinuous RV jump, which strongly depends on the spectral type of the observed star: from 14 m/s for late F-type stars, to -3 m/s for M dwarfs. Conclusions. Our NZP-corrected SERVAL RVs can be retrieved from a user-friendly, public database. It provides more than 212 000 RVs for about 3000 stars along with many auxiliary information, NZP corrections, various activity indices, and DRS-CCF products.

[49]  arXiv:2001.05962 [pdf, other]

Title: Improving geometric and dynamical constraints on cosmology with intrinsic alignments of galaxies

Authors: Atsushi Taruya, Teppei Okumura

Comments: 6 pages, 4 figures

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

We show that the spatial correlation of the intrinsic alignments (IAs) of galaxies, measured in galaxy redshift surveys, offers a precision route to improve the geometrical and dynamical constraints on cosmology. The IA has been treated as a contaminant against cosmological probes such as weak gravitational lensing experiments, but the large-scale correlation of IAs is expected to follow the coherent large-scale matter inhomogeneities. In particular, the statistics of IA inherently possess anisotropic nature, and in combination with the conventional galaxy clustering statistics, the large-scale IA correlations help to improve the measurements of the geometric distances and growth of structure. Here, we quantify the potential power of IA, and show that with their improved measurements, the constraints on equation-of-state parameter for dark energy and Hubble parameter can be tighter than those from the clustering statistics alone by a factor of more than 1.5.

[50]  arXiv:2001.05967 [pdf, other]

Title: Delay Time Distributions of Type Ia Supernovae From Galaxy and Cosmic Star Formation Histories

Authors: Louis-Gregory Strolger, Steven A. Rodney, Camilla Pacifici, Gautham Narayan, Or Graur

Comments: 20 pages, including 14 figures

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

\begin{abstract} We present analytical reconstructions of type Ia supernova (SN~Ia) delay time distributions (DTDs) by way of two independent methods: by a Markov chain Monte Carlo best-fit technique comparing the volumetric SN~Ia rate history to today's compendium cosmic star-formation history, and secondly through a maximum likelihood analysis of the star formation rate histories of individual galaxies in the GOODS/CANDELS field, in comparison to their resultant SN~Ia yields. {We adopt a flexible skew-normal DTD model, which could match a wide rage of physically-motivated DTD forms.} We find a family of solutions that are essentially exponential DTDs, similar in shape to the $\beta\approx-1$ power-law DTDs, but with more delayed events ($>1$ Gyr in age) than prompt events ($<1$ Gyr). {Comparing these solutions to delay time measures separately derived from field galaxies and galaxy clusters, we fined the skew-normal solutions can accommodate both without requiring a different DRTD form in different environments}. These model {fits} are generally inconsistent with results from single-degenerate binary populations synthesis models, and are seemingly supportive of double-degenerate progenitors for most SN~Ia events.

[51]  arXiv:2001.05971 [pdf, other]

Title: The accretion rates and mechanisms of Herbig Ae/Be stars

Authors: C. Wichittanakom, R. D. Oudmaijer, J. R. Fairlamb, I. Mendigutía, M. Vioque, K. M. Ababakr

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

This work presents a spectroscopic study of 163 Herbig Ae/Be stars. Amongst these, we present new data for 30 objects. Stellar parameters such as temperature, reddening, mass, luminosity and age are homogeneously determined. Mass accretion rates are determined from $\rm H\alpha$ emission line measurements. Our data is complemented with the X-Shooter sample from previous studies and we update results using Gaia DR2 parallaxes giving a total of 78 objects with homogeneously determined stellar parameters and mass accretion rates. In addition, mass accretion rates of an additional 85 HAeBes are determined. We confirm previous findings that the mass accretion rate increases as a function of stellar mass, and the existence of a different slope for lower and higher mass stars respectively. The mass where the slope changes is determined to be $3.98^{+1.37}_{-0.94}\,\rm M_{\odot}$. We discuss this break in the context of different modes of disk accretion for low- and high mass stars. Because of their similarities with T Tauri stars, we identify the accretion mechanism for the late-type Herbig stars with the Magnetospheric Accretion. The possibilities for the earlier-type stars are still open, we suggest the Boundary Layer accretion model may be a viable alternative. Finally, we investigated the mass accretion - age relationship. Even using the superior Gaia based data, it proved hard to select a large enough sub-sample to remove the mass dependency in this relationship. Yet, it would appear that the mass accretion does decline with age as expected from basic theoretical considerations.

[52]  arXiv:2001.05988 [pdf, other]

Title: Robo-AO M Dwarf Multiplicity Survey: Catalog

Authors: Claire Lamman, Christoph Baranec, Zachory K. Berta-Thompson, Nicholas M. Law, Jessica Schonhut-Stasik, Carl Ziegler, Maissa Salama, Rebecca Jensen-Clem, Dmitry A. Duev, Reed Riddle, Shrinivas R. Kulkarni, Jennifer G. Winters, Jonathan M. Irwin

Comments: 16 pages, 9 figures. To be published in The Astronomical Journal

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

We analyze observations from Robo-AO's field M dwarf survey taken on the 2.1m Kitt Peak telescope and perform a multiplicity comparison with Gaia DR2. Through its laser-guided, automated system, the Robo-AO instrument has yielded the largest adaptive optics M dwarf multiplicity survey to date. After developing an interface to visually identify and locate stellar companions, we selected eleven lowsignificance Robo-AO detections for follow-up on the Keck II telescope using NIRC2. In the Robo-AO survey we find 553 candidate companions within 4" around 534 stars out of 5566 unique targets, most of which are new discoveries. Using a position cross match with DR2 on all targets, we assess the binary recoverability of Gaia DR2 and compare the properties of multiples resolved by both Robo-AO and Gaia. The catalog of nearby M dwarf systems and their basic properties presented here can assist other surveys which observe these stars, such as the NASA TESS mission.

Cross-lists for Fri, 17 Jan 20

[53]  arXiv:2001.05024 (cross-list from hep-ph) [pdf, other]

Title: A universal framework for t-channel dark matter models

Authors: Chiara Arina, Benjamin Fuks, Luca Mantani

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

We present the DMSimpt model implementation in FeynRules, which aims to offer a unique general framework allowing for all simulations relevant for simplified $t$-channel dark matter models at colliders and for the complementary cosmology calculations. We describe how to match next-to-leading-order QCD fixed-order calculations with parton showers to derive robust bounds and predictions in the context of LHC dark matter searches, and moreover validate two model restrictions (relevant for Dirac and Majorana fermionic dark matter respectively) to exemplify how to evaluate dark matter observables to constrain the model parameter space. More importantly, we emphasise how to achieve these results by using a combination of publicly available automated tools, and discuss how dark matter predictions are sensitive to the model file and software setup. All files, together with illustrative Mathematica notebooks, are available from the URL this http URL

[54]  arXiv:2001.05723 (cross-list from gr-qc) [pdf, other]

Title: Gmunu: Toward multigrid based Einstein field equations solver for general-relativistic hydrodynamics simulations

Authors: Patrick Chi-Kit Cheong, Lap-Ming Lin, Tjonnie Guang-Feng Li

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

We present a general relativistic hydrodynamics code Gmunu (General-relativistic multigrid numerical solver) which uses a multigrid method to solve the elliptic metric equations in the conformally flat condition (CFC) approximation. Most of the existing relativistic hydrodynamics codes are based on formulations which rely on a free-evolution approach of numerical relativity, where the metric variables are determined by hyperbolic equations without enforcing the constrained equations in the evolution. On the other hand, although a fully constrained-evolution formulation is theoretical more appealing and should lead to more stable and accurate simulations, such an approach is not widely used because solving the elliptic-type constrained equations during the evolution is in general more computationally expensive than hyperbolic free-evolution schemes. Multigrid methods solve differential equations with a hierarchy of discretizations and its computational cost is generally lower than other methods such as direct methods, relaxation methods, successive over-relaxation. With multigrid acceleration, one can solve the metric equations on a comparable time scale as solving the hydrodynamics equations. This would potentially make a fully constrained-evolution formulation more affordable in numerical relativity simulations. As a first step to assess the performance and robustness of multigrid methods in relativistic simulations, we develop a hydrodynamics code that makes use of standard finite-volume methods coupled with a multigrid metric solver to solve the Einstein equations in the CFC approximation. In this paper, we present the methodology and implementation of our code Gmunu and its properties and performance in some benchmarking relativistic hydrodynamics problems.

[55]  arXiv:2001.05791 (cross-list from physics.comp-ph) [pdf, other]

Title: Investigating the use of field solvers for simulating classical systems

Authors: Andrew Eberhardt, Arka Banerjee, Michael Kopp, Tom Abel

Comments: 28 pages, 14 figures. To be submitted to Phys. Rev. D

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

We explore the use of field solvers as approximations of classical Vlasov-Poisson systems. This correspondence is investigated in both electrostatic and gravitational contexts. We demonstrate the ability of field solvers to be excellent approximations of problems with cold initial condition into the non linear regime. We also investigate extensions of the Schr\"odinger-Poisson system that employ multiple stacked cold streams, and the von Neumann-Poisson equation as methods that can successfully reproduce the classical evolution of warm initial conditions. We then discuss how appropriate simulation parameters need to be chosen to avoid interference terms, aliasing, and wave behavior in the field solver solutions. We present a series of criteria clarifying how parameters need to be chosen in order to effectively approximate classical solutions.

[56]  arXiv:2001.05828 (cross-list from gr-qc) [pdf, ps, other]

Title: Dynamics of cosmological inflation and predictions for reheating in the light of 2018 PLANCK results

Authors: Matias Lopez, Nelson Videla, Grigoris Panotopoulos

Comments: 16 pages, 4 figures, submitted to EPJC

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

We study the dynamics of two concrete inflationary models, namely Spontaneous Symmetry Breaking Inflation as well as Loop Inflation. We constrain the parameters for which a viable inflationary Universe emerges using the latest PLANCK results of last year, and we give predictions for the duration of reheating as well as for the reheating temperature after inflation. Our numerical results show that baryogenesis via leptogenesis may be realized within the inflationary models considered in this work.

[57]  arXiv:2001.05909 (cross-list from gr-qc) [pdf, other]

Title: Primordial black holes and secondary gravitational waves from k/G inflation

Authors: Jiong Lin, Qing Gao, Yungui Gong, Yizhou Lu, Chao Zhang, Fengge Zhang

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

The possibility that in the mass range around $10^{-12}\ M_\odot$ most of dark matter constitutes of primordial black holes (PBHs) is a very interesting topic. To produce PBHs with this mass, the primordial scalar power spectrum needs to be enhanced to the order of 0.01 at the scale $k\sim 10^{12}\ \text{Mpc}^{-1}$. The enhanced power spectrum also produces large secondary gravitational waves at the mHz band. A phenomenological delta function power spectrum is usually used to discuss the production of PBHs and secondary gravitational waves. Based on G and k inflations, we propose a new mechanism to enhance the power spectrum at small scales by introducing a non-canonical kinetic term $[1-2G(\phi)]X$ with the function $G(\phi)$ having a peak. Away from the peak, $G(\phi)$ is negligible and we recover the usual slow-roll inflation which is constrained by the cosmic microwave background anisotrpy observations. Around the peak, the slow-roll inflation transiently turns to ultra slow-roll inflation. The enhancement of the power spectrum can be obtained with generic potentials, and there is no need to fine tune the parameters in $G(\phi)$. The energy spectrum $\Omega_{GW}(f)$ of secondary gravitational waves have the characteristic power law behaviour $\Omega_{GW}(f)\sim f^{n}$ and is testable by pulsar timing array and space based gravitational wave detectors.

[58]  arXiv:2001.05965 (cross-list from stat.ME) [pdf, ps, other]

Title: The Widely Linear Complex Ornstein-Uhlenbeck Process with Application to Polar Motion

Authors: Adam M. Sykulski, Sofia C. Olhede, Hanna M. Sykulska-Lawrence

Comments: Submitted for peer-review

Subjects: Methodology (stat.ME); Earth and Planetary Astrophysics (astro-ph.EP); Signal Processing (eess.SP); Data Analysis, Statistics and Probability (physics.data-an); Applications (stat.AP)

Complex-valued and widely linear modelling of time series signals are widespread and found in many applications. However, existing models and analysis techniques are usually restricted to signals observed in discrete time. In this paper we introduce a widely linear version of the complex Ornstein-Uhlenbeck (OU) process. This is a continuous-time process which generalises the standard complex-valued OU process such that signals generated from the process contain elliptical oscillations, as opposed to circular oscillations, when viewed in the complex plane. We determine properties of the widely linear complex OU process, including the conditions for stationarity, and the geometrical structure of the elliptical oscillations. We derive the analytical form of the power spectral density function, which then provides an efficient procedure for parameter inference using the Whittle likelihood. We apply the process to measure periodic and elliptical properties of Earth's polar motion, including that of the Chandler wobble, for which the standard complex OU process was originally proposed.

[59]  arXiv:2001.05973 (cross-list from hep-ph) [pdf, other]

Title: Upper limit on first-order electroweak phase transition strength

Authors: Shehu AbdusSalam, Layla Kalhor, Mohammad Javad Kazemi

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

For a cosmological first-order electroweak phase transition, requiring no sphaleron washout of baryon number violating processes leads to a lower bound on the strength of the transition. The phases interface, the so-called bubble wall, velocity can become ultra-relativistic if the friction on the wall due to primordial plasma of particles surrounding it is not sufficient to retard the wall acceleration down to a steady speed. This bubble "runs away" should not occur if a successful baryon asymmetry generation due to the transition is required. Using Boedeker-Moore criterion for bubble wall runaway, within the context of an extension of the standard model of particle physics with a real gauge-single scalar field, we show that a non runaway transition requirement puts an upper bound on the strength of the first-order phase transition.

[60]  arXiv:2001.05980 (cross-list from hep-ph) [pdf, other]

Title: Prospects for discovering supersymmetric long-lived particles with MoEDAL

Authors: D. Felea, J. Mamuzic, R. Masełek, N. E. Mavromatos, V. A. Mitsou, J. L. Pinfold, R. Ruiz de Austri, K. Sakurai, A. Santra, O. Vives

Comments: 10 pages, 5 figures, preliminary results of this article were presented in DISCRETE 2018, arXiv:1903.11022

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

We present a study on the possibility of searching for long-lived supersymmetric partners with the MoEDAL experiment at the LHC. MoEDAL is sensitive to highly ionising objects such as magnetic monopoles or massive (meta)stable electrically charged particles. We focus on prospects of detecting long-lived sleptons in phenomenologically realistic models, not yet excluded by the current data from ATLAS or CMS, and also compatible with astrophysical constraints. Using Monte Carlo simulation, we compare the sensitivities of MoEDAL versus ATLAS and we present scenarios where MoEDAL can provide discovery reach complementary to ATLAS and CMS. It is also interesting to point out that, in such scenarios, in which charged staus are the main long-lived candidates, the relevant mass range for MoEDAL is compatible with a potential role of Supersymmetry in providing an explanation for the anomalous events observed by the ANITA detector.

Replacements for Fri, 17 Jan 20

[61]  arXiv:1611.08552 (replaced) [pdf, other]

Title: Investigating overdensities around z>6 galaxies through ALMA observations of [CII]

Authors: Tim B. Miller, Scott C. Chapman, Christopher C. Hayward, Peter S. Behroozi, C. Matt Bradford, Chris J. Willott, Jeff Wagg

Comments: Accepted for publication in ApJ

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

[62]  arXiv:1801.01493 (replaced) [pdf, other]

Title: NGC 4993, the shell galaxy host of GW170817: constraints on the recent galactic merger

Authors: Ivana Ebrová, Michal Bílek, Mustafa K. Yıldız, Jiří Eliášek

Comments: 11 pages, 7 figures, 1 table, v4:minor corrections; accepted for publication in A&A

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

[63]  arXiv:1904.04204 (replaced) [pdf, other]

Title: Classification of pulsars with Dirichlet process Gaussian mixture model

Authors: F. Ay, G. İnce, M. E. Kamaşak, K. Y. Ekşi

Comments: Accepted by MNRAS (14 January 2020). 11 pages, 4 figures, 7 tables

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Machine Learning (cs.LG); Machine Learning (stat.ML)

[64]  arXiv:1905.08951 (replaced) [pdf, ps, other]

Title: Globular Cluster Formation from Colliding Substructure

Authors: Piero Madau, Alessandro Lupi, Juerg Diemand, Andreas Burkert, Douglas N. C. Lin

Comments: 15 pages, 5 figures, accepted for publication by the Astrophysical Journal

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

[65]  arXiv:1905.09582 (replaced) [pdf, other]

Title: Thermodynamic Evolution of Secluded Vector Dark Matter: Conventional WIMPs and Nonconventional WIMPs

Authors: Kwei-Chou Yang

Comments: 51 pages, 15 figures; variations of the local density and inner log slope of the halo corrected to be consistent with the plots (see for instance the caption of Fig. 6)

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

[66]  arXiv:1905.10198 (replaced) [pdf, other]

Title: Implications of a transition in the dark energy equation of state for the $H_0$ and $σ_8$ tensions

Authors: Ryan E. Keeley, Shahab Joudaki, Manoj Kaplinghat, David Kirkby

Comments: 24 pages, 16 figures

Journal-ref: Journal of Cosmology and Astroparticle Physics, Issue 12, article id. 035 (2019)

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

[67]  arXiv:1905.10216 (replaced) [pdf, other]

Title: Debiasing Cosmic Gravitational Wave Sirens

Authors: Ryan E. Keeley, Arman Shafieloo, Benjamin L'Huillier, Eric V. Linder

Comments: 8 pages, 7 figures

Journal-ref: Monthly Notices of the Royal Astronomical Society, Volume 491, Issue 3, January 2020, p.3983-3989

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

[68]  arXiv:1908.05316 (replaced) [pdf, other]

Title: The optically-selected 1.4-GHz quasar luminosity function below 1 mJy

Authors: Eliab Malefahlo, Mario G. Santos, Matt J. Jarvis, Sarah V. White, Jonathan T. L. Zwart

Comments: 20 pages, 14 figures, 5 tables

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

[69]  arXiv:1908.08247 (replaced) [pdf, other]

Title: Constraints on Quasi-dilaton Massive Gravity

Authors: Katarina Martinovic, Mairi Sakellariadou

Comments: 8 pages

Journal-ref: Phys. Rev. D 100, 124016 (2019)

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

[70]  arXiv:1909.02824 (replaced) [pdf, other]

Title: The impact of non-dipolar magnetic fields in core-collapse supernovae

Authors: M. Bugli, J. Guilet, M. Obergaulinger, P. Cerdá-Durán, M. Á. Aloy

Comments: 15 pages, 15 figures; published in MNRAS

Journal-ref: MNRAS, Volume 492, Issue 1, p.58-71, February 2020

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

[71]  arXiv:1909.06603 (replaced) [pdf, other]

Title: Timing Terminators: Forecasting Sunspot Cycle 25 Onset

Authors: Robert J Leamon, Scott W. McIntosh, Sandra C. Chapman, Nicholas W. Watkins

Comments: 18 pages, 6 figures, 1 table. Final (minor corrections) revision as submitted to Solar Physics, January 2020

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

[72]  arXiv:1909.09645 (replaced) [pdf, other]

Title: The Effect of Star--Disk Interactions on Highly Eccentric Stellar Orbits in Active Galactic Nuclei: A Disk Loss Cone and Implications for Stellar Tidal Disruption Events

Authors: Morgan MacLeod, Douglas N. C. Lin

Comments: Submitted to AAS Journals; comments are welcome. Associated software at: this https URL

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

[73]  arXiv:1910.04687 (replaced) [pdf, other]

Title: The Shock Physics of Giant Impacts: Key Requirements for the Equations of State

Authors: Sarah T. Stewart, Erik J. Davies, Megan S. Duncan, Simon J. Lock, Seth Root, Joshua P. Townsend, Richard G. Kraus, Razvan Caracas, Stein B. Jacobsen

Comments: M-ANEOS source code public release (this https URL); forsterite EOS public release (this https URL); manuscript accepted (no changes): Stewart, S., et al. (accepted). In J. Lane, T. Germann, and M. Armstrong (Eds.), 21st Biennial APS Conference on Shock Compression of Condensed Matter (SCCM19). AIP Publishing

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

[74]  arXiv:1910.05633 (replaced) [pdf, other]

Title: Velocity-dependent self-interacting dark matter from thermal freeze-out and tests in direct detections

Authors: Lian-Bao Jia

Comments: 10 pages, 6 figures, the accepted version

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

[75]  arXiv:1910.09038 (replaced) [pdf, other]

Title: Testing the Spectroscopic Extraction of Suppression of Convective Blueshift

Authors: M. Miklos, T. W. Milbourne, R. D. Haywood, D. F. Phillips, S. H. Saar, N. Meunier, H. M. Cegla, X. Dumusque, N. Langellier, J. Maldonado, L. Malavolta, A. Mortier, S. Thompson, C. A. Watson, M. Cecconi, R. Cosentino, A. Ghedina, C-H. Li, M. López-Morales, E. Molinari, E. Poretti, D. Sasselov, A. Sozzetti, R. L. Walsworth

Comments: 8 pages, 4 figures, 4 tables, Published by ApJ (1/15/2020)

Journal-ref: The Astrophysical Journal, 888:117(6pp), 2020

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

[76]  arXiv:1911.02773 (replaced) [pdf, ps, other]

Title: The use of a Kepler solver in numerical integrations of quasi-Keplerian orbits

Authors: Chen Deng, Xin Wu, Enwei Liang

Comments: 17 pages,11 figures

Subjects: General Relativity and Quantum Cosmology (gr-qc); Solar and Stellar Astrophysics (astro-ph.SR)

[77]  arXiv:1911.09772 (replaced) [pdf, other]

Title: Spectral swaps in a two-dimensional neutrino ring model

Authors: Joshua D. Martin, J. Carlson, Huaiyu Duan

Comments: 9 pages, 6 figures

Journal-ref: Phys. Rev. D 101, 023007 (2020)

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

[78]  arXiv:1912.07704 (replaced) [pdf, ps, other]

Title: Development of production-ready GPU data processing pipeline software for AstroAccelerate

Authors: Cees Carels, Karel Adámek, Jan Novotný, Wesley Armour

Comments: 4 pages, 2 figures. ASP Conference Series in preparation. Credit is hereby given to the ASP Conference Series. To appear in proceedings of The Annual Conference on Astronomical Data Analysis and Software Systems (ADASS) 2019

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

[79]  arXiv:1912.08820 (replaced) [pdf, other]

Title: Survival of Primordial Planetary Atmospheres: Mass Loss from Temperate Terrestrial Planets

Authors: Alex R. Howe, Fred C. Adams, Michael R. Meyer

Comments: Resubmitted to ApJ. This draft revises mass loss estimates. (24 pages, 1 figure, 3 tables)

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

[80]  arXiv:2001.00638 (replaced) [pdf, other]

Title: Nonsingular Ekpyrotic Cosmology with a Nearly Scale-Invariant Spectrum of Cosmological Perturbations and Gravitational Waves

Authors: Robert Brandenberger, Ziwei Wang (McGill University)

Comments: 9 pages, a few typos corrected and references updated

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

[81]  arXiv:2001.01209 (replaced) [pdf, other]

Title: Dark Matter in CCDs at Modane (DAMIC-M): a silicon detector apparatus searching for low-energy physics processes

Authors: Steven Juhyung Lee, Ben Kilminster, Anna Macchiolo

Comments: Proceeding for the IPRD19 conference

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

[82]  arXiv:2001.02230 (replaced) [pdf, other]

Title: The stellar-to-halo mass relation over the past 12 Gyr

Authors: Giacomo Girelli, Lucia Pozzetti, Micol Bolzonella, Carlo Giocoli, Federico Marulli, Marco Baldi

Comments: accepted for publication in A&A, matching version in press

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

[83]  arXiv:2001.03389 (replaced) [pdf, other]

Title: Real-Time RFI Mitigation for the Apertif Radio Transient System

Authors: Alessio Sclocco, Dany Vohl, Rob V. van Nieuwpoort

Comments: 6 pages, 10 figures. To appear in Proceedings from the 2019 Radio Frequency Interference workshop (RFI 2019), Toulouse, France (23-26 September)

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Distributed, Parallel, and Cluster Computing (cs.DC)

[84]  arXiv:2001.04354 (replaced) [pdf, ps, other]

Title: The AGORA high-resolution galaxy simulations comparison project: Public data release

Authors: Santi Roca-Fàbrega, Ji-hoon Kim, Joel R. Primack, Michael J. Butler, Daniel Ceverino, Jun-Hwan Choi, Robert Feldmann, Ben W. Keller, Alessandro Lupi, Kentaro Nagamine, Thomas R. Quinn, Yves Revaz, Romain Teyssier, Spencer C. Wallace (for the AGORA Collaboration)

Comments: AGORA links: this http URL and this http URL

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

[85]  arXiv:2001.04479 (replaced) [pdf, other]

Title: A panchromatic spatially-resolved analysis of nearby galaxies: sub-kpc scale Main Sequence in grand-design spirals

Authors: A. Enia, G. Rodighiero, L. Morselli, V. Casasola, S. Bianchi, L. Rodriguez-Munoz, C. Mancini, A. Renzini, P. Popesso, P. Cassata, M. Negrello, A. Franceschini

Comments: 21 pages, 15 figures. Submitted to MNRAS

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

[86]  arXiv:2001.04973 (replaced) [pdf, other]

Title: On the Inference of a Star's Inclination Angle from its Rotation Velocity and Projected Rotation Velocity

Authors: Kento Masuda (IAS), Joshua N. Winn (Princeton)

Comments: accepted for publication in AJ [7 pages]

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

[87]  arXiv:2001.05004 (replaced) [pdf, other]

Title: The Observational Anatomy of Externally Photoevaporating Planet-Forming Discs I: Atomic Carbon

Authors: Thomas J. Haworth, James E. Owen

Comments: 12 pages, accepted for publication in MNRAS

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

[88]  arXiv:2001.05020 (replaced) [pdf, ps, other]

Title: NuSTAR Observations and multi-wavelength modeling of the high-redshift BL Lac Object 4FGL J2146.5-1344

Authors: M. Rajagopal, L. Marcotulli, M. Ajello, A. Kaur, V. Paliya, D. Hartmann

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

• New submissions
• Cross-lists
• Replacements