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New submissions for Tue, 7 Jan 20

[1]  arXiv:2001.00941 [pdf, other]

Title: The LSST DESC Data Challenge 1: Generation and Analysis of Synthetic Images for Next Generation Surveys

Authors: F. Javier Sánchez, Chris W. Walter, Humna Awan, James Chiang, Scott F. Daniel, Eric Gawiser, Tom Glanzman, David P. Kirkby, Rachel Mandelbaum, Anže Slosar, W. Michael Wood-Vasey, Yusra AlSayyad, Colin J. Burke, Seth W. Digel, Mike Jarvis, Tony Johnson, Heather Kelly, Simon Krughoff, Robert H. Lupton, Phil J. Marshall, John R. Peterson, Paul A. Price, Glenn Sembroski, Brian Van Klaveren, Matthew P. Wiesner, Bo Xin (for the LSST Dark Energy Science Collaboration)

Comments: 20 pages, 22 figures. Submitted to MNRAS

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

Data Challenge 1 (DC1) is the first synthetic dataset produced by the Large Synoptic Survey Telescope (LSST) Dark Energy Science Collaboration (DESC). These are designed to develop and validate data reduction and analysis and to study the impact of systematic effects that will affect the LSST dataset. DC1 is comprised of $r$-band observations of 40 deg$^{2}$ to 10-year LSST depth. We present each stage of the simulation and analysis process: a) generation, by synthesizing sources from cosmological N-body simulations in individual sensor-visit images with different observing conditions; b) reduction using a development version of the LSST Science Pipelines; and c) matching to the input cosmological catalog for validation and testing. We study our processed catalogs compared to the LSST requirements key performance metrics (KPMs). We establish a set of pipeline flags that produce a sufficiently clean extragalactic sample and we discuss residual sample contamination, including contributions from inefficiency in star-galaxy separation and imperfect deblending. We compute the galaxy power spectrum on the simulated field. Our main conclusions are: i) realistic and validated synthetic datasets will be required for successfully controlling systematics; ii) within the fidelity of DC1, the LSST Science Pipelines pass all testable KPMs; iii) there is no unique noiseless method for matching the input and output catalogs; iv) the presence of bright objects has a significant impact (2- to 6-$\sigma$) in the estimated power spectra at small scales ($\ell > 1200$), highlighting the impact of blending in studies at small angular scales in LSST.

[2]  arXiv:2001.00945 [pdf, ps, other]

Title: Equivalence of the Fermat potential and the lensing potential approaches to computing the integrated Sachs-Wolfe effect

Authors: R. Kantowski, B. Chen, X. Dai

Comments: 14 pages. arXiv admin note: text overlap with arXiv:1410.4608

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

We show in detail that the recently derived expression for evaluating the integrated Sachs-Wolfe (ISW) temperature shift in the cosmic microwave background (CMB) caused by individual embedded (compensated) lenses is equivalent to the conventional approach for flat background cosmologies. The conventional approach requires evaluating an integral of the time derivative of the lensing potential, whereas the new Fermat potential approach is simpler and only requires taking a derivative of the potential part of the time delay.

[3]  arXiv:2001.00949 [pdf, ps, other]

Title: Post-main-sequence debris from rotation-induced YORP break-up of small bodies II: multiple fissions, internal strengths and binary production

Authors: Dimitri Veras, Daniel J. Scheeres

Comments: Accepted for publication in MNRAS

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

Over one quarter of white dwarfs contain observable metallic debris from the breakup of exo-asteroids. Understanding the physical and orbital history of this debris would enable us to self-consistently link planetary system formation and fate. One major debris reservoir is generated by YORP-induced rotational fission during the giant branch phases of stellar evolution, where the stellar luminosity can exceed the Sun's by four orders of magnitude. Here, we determine the efficacy of the giant branch YORP effect for asteroids with nonzero internal strength, and model post-fission evolution by imposing simple analytic fragmentation prescriptions. We find that even the highest realistic internal strengths cannot prevent the widespread fragmentation of asteroids and the production of a debris field over 100 au in size. We compute the number of successive fission events as they occur in progressively smaller time intervals as the star ascends the giant branches, providing a way to generate size distributions of asteroid fragments. The results are highly insensitive to progenitor stellar mass. We also conclude that the ease with which giant branch YORP breakup can generate binary asteroid subsystems is strongly dependent on internal strength. Formed binary subsystems in turn could be short-lived due to the resulting luminosity-enhanced BYORP effect.

[4]  arXiv:2001.00950 [pdf, other]

Title: Ready, set, launch: time interval between BNS merger and short GRB jet formation

Authors: Paz Beniamini, Rodolfo Barniol Duran, Maria Petropoulou, Dimitrios Giannios

Comments: 10 pages, 7 figures

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

The joint detection of GW~170817/GRB 170817 confirmed the long-standing theory that binary neutron star mergers produce short gamma-ray burst (sGRB) jets that can successfully break out of the surrounding ejecta. At the same time, the association with a kilonova provided unprecedented information regarding the physical properties (such as masses and velocities) of the different ejecta constituents. Combining this knowledge with the observed luminosities and durations of cosmological sGRBs detected by the Burst Alert Telescope (BAT) onboard the Neil Gehrels Swift Observatory, we revisit the breakout conditions of sGRB jets. We find that the time interval between the binary merger and the launching of a typical sGRB jet is $\lesssim0.1$~s. We also show that for a fraction of at least $\sim 30\%$ of sGRBs, the usually adopted assumption of static ejecta is inconsistent with observations, even if the polar ejecta mass is an order of magnitude smaller than the one in GRB 170817. Our results disfavour magnetar central engines for powering cosmological sGRBs, limit the amount of energy deposited in the cocoon prior to breakout, and suggest that the observed delay of $\sim 1.$7~s in GW 170817 /GRB 170817 between the gravitational wave and $\gamma$-ray signals is likely dominated by the propagation time of the jet to the $\gamma$-ray production site.

[5]  arXiv:2001.00951 [pdf, other]

Title: Realistic On-the-fly Outcomes of Planetary Collisions II: Bringing Machine Learning to N-body Simulations

Authors: Alexandre Emsenhuber, Saverio Cambioni, Erik Asphaug, Travis S. J. Gabriel, Stephen R. Schwartz, Roberto Furfaro

Comments: 20 pages, 10 figures, 3 tables; accepted for publication in ApJ; Table 1 is available in full in an ancillary file; the code developed in this work is available at this https URL

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

Terrestrial planet formation theory is at a bottleneck, with the growing realization that pairwise collisions are treated far too simply. Here, and in our companion paper (Cambioni et al. 2019) that introduces the training methodology, we demonstrate the first application of machine learning to more realistically model the late stage of planet formation by giant impacts. We present surrogate models that give fast, reliable answers for the masses and velocities of the two largest remnants of a giant impact, as a function of the colliding masses and their impact velocity and angle, with the caveat that our training data do not yet include pre-impact rotation or variable thermal conditions. We compare canonical N-body scenarios of terrestrial planet formation assuming perfect merger (Chambers 2001) with our more realistic treatment that includes inefficient accretions and hit-and-run collisions. The result is a protracted tail of final events lasting ~200 Myr, and the conversion of about half the mass of the initial population to debris. We obtain profoundly different solar system architectures, featuring a much wider range of terrestrial planet masses and enhanced compositional diversity.

[6]  arXiv:2001.00952 [pdf, other]

Title: The First Habitable Zone Earth-sized Planet from TESS. I: Validation of the TOI-700 System

Authors: Emily A. Gilbert, Thomas Barclay, Joshua E. Schlieder, Elisa V. Quintana, Benjamin J. Hord, Veselin B. Kostov, Eric D. Lopez, Jason F. Rowe, Kelsey Hoffman, Lucianne M. Walkowicz, Michele L. Silverstein, Joseph E. Rodriguez, Andrew Vanderburg, Gabrielle Suissa, Vladimir S. Airapetian, Matthew S. Clement, Sean N. Raymond, Andrew W. Mann, Ethan Kruse, Jack J. Lissauer, Knicole D. Colón, Ravi kumar Kopparapu, Laura Kreidberg, Sebastian Zieba, Karen A. Collins, Samuel N. Quinn, Steve B. Howell, Carl Ziegler, Eliot Halley Vrijmoet, Fred C. Adams, Giada N. Arney, Patricia T. Boyd, Jonathan Brande, Christopher J. Burke, Luca Cacciapuoti, Quadry Chance, Jessie L. Christiansen, Giovanni Covone, Tansu Daylan, Danielle Dineen, Courtney D. Dressing, Zahra Essack, Thomas J. Fauchez, Brianna Galgano, et al. (51 additional authors not shown)

Comments: 29 pages, 15 figures, 4 tables, submitted to AAS Journals

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

We present the discovery and validation of a three-planet system orbiting the nearby (31.1 pc) M2 dwarf star TOI-700 (TIC 150428135). TOI-700 lies in the TESS continuous viewing zone in the Southern Ecliptic Hemisphere; observations spanning 11 sectors reveal three planets with radii ranging from 1 R$_\oplus$ to 2.6 R$_\oplus$ and orbital periods ranging from 9.98 to 37.43 days. Ground-based follow-up combined with diagnostic vetting and validation tests enable us to rule out common astrophysical false-positive scenarios and validate the system of planets. The outermost planet, TOI-700 d, has a radius of $1.19\pm0.11$ R$_\oplus$ and resides in the conservative habitable zone of its host star, where it receives a flux from its star that is approximately 86% of the Earth's insolation. In contrast to some other low-mass stars that host Earth-sized planets in their habitable zones, TOI-700 exhibits low levels of stellar activity, presenting a valuable opportunity to study potentially-rocky planets over a wide range of conditions affecting atmospheric escape. While atmospheric characterization of TOI-700 d with the James Webb Space Telescope (JWST) will be challenging, the larger sub-Neptune, TOI-700 c (R = 2.63 R$_\oplus$), will be an excellent target for JWST and beyond. TESS is scheduled to return to the Southern Hemisphere and observe TOI-700 for an additional 11 sectors in its extended mission, which should provide further constraints on the known planet parameters and searches for additional planets and transit timing variations in the system.

[7]  arXiv:2001.00953 [pdf, other]

Title: Cloud formation in the atomic and molecular phase: HI self absorption (HISA) towards a Giant Molecular Filament

Authors: Y. Wang, S. Bihr, H. Beuther, M. R. Rugel, J. D. Soler, J. Ott, J. Kainulainen, N. Schneider, R. S. Klessen, S. C. O. Glover, N. M. McClure-Griffiths, P. F. Goldsmith, K. G. Johnston, K. M. Menten, S. Ragan, L. D. Anderson, J. S. Urquhart, H. Linz, N. Roy, R. J. Smith, F. Bigiel, T. Henning, S. N. Longmore

Comments: 22 pages, 25 figures, accepted for publication by A&A

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

Molecular clouds form from the atomic phase of the interstellar medium. However, characterizing the transition between the atomic and the molecular interstellar medium (ISM) is a difficult observational task. Here we address cloud formation processes by combining HSIA with molecular line data. One scenario proposed by numerical simulations is that the column density probability density functions (N-PDF) evolves from a log-normal shape at early times to a power-law-like shape at later times. In this paper, we study the cold atomic component of the giant molecular filament GMF38a (d=3.4 kpc, length$\sim230$ pc). We identify an extended HISA feature, which is partly correlated with the 13CO emission. The peak velocities of the HISA and 13CO observations agree well on the eastern side of the filament, whereas a velocity offset of approximately 4 km s$^{-1}$ is found on the western side. The sonic Mach number we derive from the linewidth measurements shows that a large fraction of the HISA, which is ascribed to the cold neutral medium (CNM), is at subsonic and transonic velocities. The column density of the CNM is on the order of 10$^{20}$ to 10$^{21}$ cm$^{-2}$. The column density of molecular hydrogen is an order of magnitude higher. The N-PDFs from HISA (CNM), HI emission (WNM+CNM), and 13CO (molecular component) are well described by log-normal functions, which is in agreement with turbulent motions being the main driver of cloud dynamics. The N-PDF of the molecular component also shows a power law in the high column-density region, indicating self-gravity. We suggest that we are witnessing two different evolutionary stages within the filament. The eastern subregion seems to be forming a molecular cloud out of the atomic gas, whereas the western subregion already shows high column density peaks, active star formation and evidence of related feedback processes.

[8]  arXiv:2001.00954 [pdf, other]

Title: The First Habitable Zone Earth-Sized Planet From TESS II: $Spitzer$ Confirms TOI-700 d

Authors: Joseph E. Rodriguez, Andrew Vanderburg, Sebastian Zieba, Laura Kreidberg, Caroline V. Morley, Stephen R. Kane, Alton Spencer, Samuel N. Quinn, Jason D. Eastman, Ryan Cloutier, Chelsea X. Huang, Karen A. Collins, Andrew W. Mann, Emily Gilbert, Joshua E. Schlieder, Elisa V. Quintana, Thomas Barclay, Gabrielle Suissa, Ravi kumar Kopparapu, Courtney D. Dressing, George R. Ricker, Roland K. Vanderspek, David W. Latham, Sara Seager, Joshua N. Winn, Jon M. Jenkins, Zachory Berta-Thompson, Patricia T. Boyd, David Charbonneau, Douglas A. Caldwell, Eugene Chiang, Jessie L. Christiansen, David R. Ciardi, Knicole D. Colón, John Doty, Tianjun Gan, Natalia Guerrero, Maximilian N. Günther, Eve J. Lee, Alan M. Levine, Eric Lopez, Philip S. Muirhead, Elisabeth Newton, Mark E. Rose, Joseph D. Twicken, et al. (1 additional author not shown)

Comments: 13 Pages, 3 Figures, 2 Tables, Submitted to the AAS Journals (12/22/2019), Some revisions from minor referee report

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

We present $Spitzer$ 4.5$\mu$m observations of the transit of TOI-700 d, a habitable zone Earth-sized planet in a multiplanet system transiting a nearby M-dwarf star (TIC 150428135, 2MASS J06282325-6534456). TOI-700 d has a radius of $1.220^{+0.073}_{-0.063}R_\oplus$ and orbits within its host star's conservative habitable zone with a period of 37.42 days ($T_\mathrm{eq} \sim 269$ K). TOI-700 also hosts two small inner planets (R$_b$=$1.044^{+0.065}_{-0.063}R_\oplus$ & R$_c$=$2.64^{+0.16}_{-0.14}R_\oplus$) with periods of 9.98 and 16.05 days, respectively. Our $Spitzer$ observations confirm the TESS detection of TOI-700 d and remove any remaining doubt that it is a genuine planet. We analyze the $Spitzer$ light curve combined with the 11 sectors of TESS observations and a transit of TOI-700 c from the LCOGT network to determine the full system parameters. With an expected RV semi-amplitude of $\sim$80 cm/s, it may be possible to measure the mass of TOI-700 d using state-of-the-art radial velocity instruments.

[9]  arXiv:2001.00955 [pdf, other]

Title: The First Habitable Zone Earth-sized Planet from TESS. III: Climate States and Characterization Prospects for TOI-700 d

Authors: Gabrielle Suissa, Eric T. Wolf, Ravi kumar Kopparapu, Geronimo L. Villanueva, Thomas Fauchez, Avi M. Mandell, Giada Arney, Emily A. Gilbert, Joshua E. Schlieder, Thomas Barclay, Elisa V. Quintana, Eric Lopez, Joseph E. Rodriguez, Andrew Vanderburg

Comments: Submitted to AJ, 21 pages, 11 figures

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

We present self-consistent three-dimensional climate simulations of possible habitable states for the newly discovered Habitable Zone Earth-sized planet, TOI-700 d. We explore a variety of atmospheric compositions, pressures, and rotation states for both ocean-covered and completely desiccated planets in order to assess the planet's potential for habitability. For all 20 of our simulated cases, we use our climate model outputs to synthesize transmission spectra, combined-light spectra, and integrated broadband phase curves. These climatologically-informed observables will help the community assess the technological capabilities necessary for future characterization of this planet, as well as distinguish possible climate states if one day we do obtain sensitive spectral observations. We find that TOI-700 d is a robust candidate for a habitable world and can potentially maintain temperate surface conditions under a wide variety of atmospheric compositions. Unfortunately, the spectral feature depths from the resulting transmission spectra and the peak flux and variations from our synthesized phase curves do not exceed 10 ppm. This will likely prohibit the James Webb Space Telescope (JWST) from characterizing its atmosphere; however, this motivates the community to invest in future instrumentation that perhaps can one day reveal the true nature of TOI-700 d.

[10]  arXiv:2001.00963 [pdf, other]

Title: Non-singular recursion formulas for third-body perturbations in mean vectorial elements

Authors: M. Lara, A. J. Rosengren, E. Fantino

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

The description of the long-term dynamics of highly elliptic orbits under third-body perturbations may require an expansion of the disturbing function in series of the semi-major axes ratio up to higher orders. To avoid dealing with long series in trigonometric functions, we refer the motion to the apsidal frame and efficiently remove the short-period effects of this expansion in vectorial form up to an arbitrary order. We then provide the variation equations of the two fundamental vectors of the Keplerian motion by analogous vectorial recurrences, which are free from singularities and take a compact form useful for the numerical propagation of the flow in mean elements.

[11]  arXiv:2001.00970 [pdf]

Title: A Native Hawaiian-led summary of the current impact of constructing the Thirty Meter Telescope on Maunakea

Authors: Sara Kahanamoku, Rosie 'Anolani Alegado, Aurora Kagawa-Viviani, Katie Leimomi Kamelamela, Brittany Kamai, Lucianne M Walkowicz, Chanda Prescod-Weinstein, Mithi Alexa de los Reyes, Hilding Neilson

Comments: Submitted to the National Academy of Sciences Decadal Survey on Astronomy and Astrophysics (Astro2020) Panel on the State of the Profession and Societal Impacts (SoP)

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

Maunakea, the proposed site of the Thirty Meter Telescope (TMT), is a lightning-rod topic for Native Hawaiians, Hawaii residents, and the international astronomy community. In this paper we, Native Hawaiian natural scientists and allies, identify historical decisions that impact current circumstances on Maunakea and provide approaches to acknowledging their presence. Our aim is to provide an Indigenous viewpoint centered in Native Hawaiian perspectives on the impacts of the TMT project on the Hawaiian community. We summarize the current Maunakea context from the perspective of the authors who are trained in the natural sciences (inclusive of and beyond astronomy and physics), the majority of whom are Native Hawaiian or Indigenous. We highlight three major themes in the conflict surrounding TMT: 1) physical demonstrations and the use of law enforcement against the protectors of Maunakea; 2) an assessment of the benefit of Maunakea astronomy to Native Hawaiians; and 3) the disconnect between astronomers and Native Hawaiians. We close with general short- and long- term recommendations for the astronomy community, which represent steps that can be taken to re-establish trust and engage in meaningful reciprocity and collaboration with Native Hawaiians and other Indigenous communities. Our recommendations are based on established best principles of free, prior, and informed consent and researcher-community interactions that extend beyond transactional exchanges. We emphasize that development of large-scale astronomical instrumentation must be predicated on consensus from the local Indigenous community about whether development is allowed on their homelands. Proactive steps must be taken to center Indigenous voices in the earliest stages of project design.

[12]  arXiv:2001.00982 [pdf, other]

Title: The origin of the power-law form of the extragalactic gamma-ray flux

Authors: Paolo Lipari

Comments: 26 pages, 10 figures

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

The Fermi-LAT telescope has measured the extragalactic gamma-ray background (EGB) generated by the ensemble of all extragalactic sources. The energy distribution of the EGB is well described as a power-law with a spectral index approximately equal to 2.3, and an exponential cutoff, that is consistent with being the effect of absorption of high energy photons assuming an emission that is an unbroken power-law spectrum. The observations of the Fermi telescope have also resolved the EGB, determining that most of it is formed by the sum of the contributions of Active Galactic Nuclei (AGN) of the blazar class. The spectra of the individual AGN sources have a broad range of spectral shapes, and the brightest and most precisely measured sources have curved spectra that can be fitted with the "log-parabola" (or log-normal) form. It might appear surprising that the sum of contributions with different spectral shapes generate a spectrum that has a simple power-law form. We suggest that this fact reveals some important properties for the ensemble of the extragalactic sources, and indicates that the blazar high energy emission can be considered as a "critical phenomenon". A curved log--parabola (log-normal) form is also required to fit the spectra of many Galactic gamma-ray sources, including the emission from the brightest supernova remnants (SNR), and an intriguing possibility is that also the Galactic cosmic rays are injected in interstellar space by their sources not with a single universal power-law spectrum, as predicted by the commonly accepted models, but instead with a broad range of spectral shapes.

[13]  arXiv:2001.01001 [pdf, other]

Title: Ondr}ejov echelle spectrograph, ground based support facility for exoplanet missions

Authors: Petr Kabath, Marek Skarka, Silvia Sabotta, Eike Guenther, David Jones, Tereza Klocova, Jan Subjak, Jiri Zak, Magdalena Spokova, Martin Blazek, Jana Dvorakova, Daniel Dupkala, Jan Fuchs, Artie Hatzes, Eva Kortusova, Radek Novotny, Eva Plavalova, Ludek Rezba, Jan Sloup, Petr Skoda, Miroslav Slechta

Comments: accepted for publication in PASP

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

Fulfilling the goals of space-based exoplanetary transit surveys, like Kepler and TESS, is impossible without ground-based spectroscopic follow-up. In particular, the first-step vetting of candidates could easily necessitate several hundreds of hours of telescope time -- an area where 2-m class telescopes can play a crucial role. Here, we describe the results from the science verification of the Ond\v{r}ejov Echelle Spectrograph (OES) installed on the 2-m Perek telescope. We discuss the performance of the instrument as well as its suitability for the study of exoplanetary candidates from space-based transit surveys. In spite of being located at an average European observing site, and originally being conceived for the study of variable stars, OES can prove to be an important instrument for the exoplanetary community in the TESS and PLATO era -- reaching accuracies of a few tens of m/s with reasonable sampling and signal-to-noise for sources down to V$\sim$13. The stability of OES is demonstrated via long-term monitoring of the standard star HD~109358, while its validity for exoplanetary candidate verification is shown using three K2 candidates EPIC~210925707, EPIC~206135267 and EPIC~211993818, to reveal that they are false positive detections.

[14]  arXiv:2001.01012 [pdf, other]

Title: The spin rates of O stars in WR + O Magellanic Cloud binaries

Authors: Michael M. Shara, Steven M. Crawford, Dany Vanbeveren, Anthony F. J. Moffat, David Zurek, Lisa Crause

Comments: 8 pages, 13 figures, accepted in MNRAS

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

Some massive, merging black holes (BH) may be descendants of binary O stars. The evolution and mass transfer between these O stars determines the spins of their progeny BH. These will be measurable with future gravitational wave detectors, incentivizing the measurement of the spins of O stars in binaries. We previously measured the spins of O stars in Galactic Wolf-Rayet (WR) + O binaries. Here we measure the vsini of four LMC and two SMC O stars in WR + O binaries to determine whether lower metallicity might affect the spin rates. We find that the O stars in Galactic and Magellanic WR + O binaries display average vsini = 258 +/- 18 km/s and 270 +/- 15 km/s, respectively. Two LMC O stars measured on successive nights show significant line width variability, possibly due to differing orbital phases exhibiting different parts of the O stars illuminated differently by their WR companions. Despite this variability, the vsini are highly super-synchronous but distinctly subcritical for the O stars in all these binaries; thus we conclude that an efficient mechanism for shedding angular momentum from O stars in WR + O binaries must exist. This mechanism, probably related to Roche lobe overflow-created dynamo magnetic fields, prevents nearly 100% breakup spin rates, as expected when RLOF operates, as it must, in these stars. A Spruit-Tayler dynamo and O star wind might be that mechanism.

[15]  arXiv:2001.01025 [pdf, other]

Title: The binary-host connection: astrophysics of gravitational wave binaries from their host galaxy properties

Authors: Susmita Adhikari, Maya Fishbach, Daniel E. Holz, Risa H. Wechsler, Zhanpei Fang

Comments: 13 pages, 9 figures, to be submitted to ApJ

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

Gravitational waves produced from the merger of binary neutron stars (BNSs) are accompanied by electromagnetic counterparts, making it possible to identify the associated host galaxy. We explore how properties of the host galaxies relate to the astrophysical processes leading to the mergers. It is thought that the BNS merger rate within a galaxy at a given epoch depends primarily on the galaxy's star-formation history as well as the underlying merger time-delay distribution of the binary systems. The stellar history of a galaxy, meanwhile, depends on the cosmological evolution of the galaxy through time, and is tied to the growth of structure in the Universe. We study the hosts of BNS mergers in the context of structure formation by populating the Universe Machine simulations with gravitational-wave events~ according to a simple time-delay model. We find that different time-delay distributions predict different properties of the associated host galaxies, including the distributions of stellar mass, star-formation rate, halo mass, and local and large-scale clustering of hosts. BNSs that merge today with short delay times prefer to be in hosts that have high star-formation rates, while those with long delay times live in dense regions within massive halos that have low star formation. We show that with ${\mathcal O}(10)$ events from current gravitational-wave detector networks, it is possible to make preliminary distinctions between formation channels which trace stellar mass, halo mass, or star-formation rate. We also find that strategies to follow up gravitational-wave events with electromagnetic telescopes can be significantly optimized using the clustering properties of their hosts.

[16]  arXiv:2001.01032 [pdf, other]

Title: Interactions of Type I X-ray Bursts with Thin Accretion Discs

Authors: P. Chris Fragile, David R. Ballantyne, Aidan Blankenship

Comments: 26 pages, 10 figures

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

We perform a set of numerical experiments studying the interaction of Type I X-ray bursts with thin, Shakura-Sunyaev type accretion discs. Careful observations of X-ray spectra during such bursts have hinted at changes occurring in the inner regions of the disc. We now clearly demonstrate a number of key effects that take place simultaneously, including: evidence for weak, radiation-driven outflows along the surface of the disc; significant levels of Poynting-Robertson (PR) drag, leading to enhanced accretion; and prominent heating in the disc, which increases the height, while lowering the density and optical depth. The PR drag causes the inner edge of the disc to retreat from the neutron star surface toward larger radii and then recover on the timescale of the burst. We conclude that the rich interaction of an X-ray burst with the surrounding disc provides a novel way to study the physics of accretion onto compact objects.

[17]  arXiv:2001.01085 [pdf, ps, other]

Title: A Convective Dredge-Up Model as the Origin of Hydrogen in DBA White Dwarfs

Authors: B. Rolland, P. Bergeron, G. Fontaine

Comments: Accepted for publication in The Astrophysical Journal (34 pages, 11 figures, 1 table)

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

We revisit the problem of the formation of DB white dwarfs, as well as the origin of hydrogen in DBA stars, using a new set of envelope model calculations with stratified and mixed hydrogen/helium compositions. We first describe an approximate model to simulate the so-called convective dilution process, where a thin, superficial hydrogen radiative layer is gradually eroded by the underlying and more massive convective helium envelope, thus transforming a DA white dwarf into a DB star. We show that this convective dilution process is able to account for the large increase in the number of DB white dwarfs below Teff ~ 20,000 K, but that the residual hydrogen abundances expected from this process are still orders of magnitude lower than those observed in DBA white dwarfs. Scenarios involving the accretion of hydrogen from the interstellar medium or other external bodies have often been invoked to explain these overabundances of hydrogen. In this paper, we describe a new paradigm where hydrogen, initially diluted within the thick stellar envelope, is still present and slowly diffusing upward in the deeper layers of a Teff ~ 20,000 K white dwarf. When the convective dilution process occurs, the bottom of the mixed H/He convection zone sinks deep into the star, resulting in large amounts of hydrogen being dredged-up to the stellar surface, a phenomenon similar to that invoked in the context of DQ white dwarfs.

[18]  arXiv:2001.01092 [pdf, other]

Title: Thermal instability revisited

Authors: Samuel Falle, Christopher Wareing, Julian Pittard

Comments: 17 pages, 15 figures

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

Field's linear analysis of thermal instability is repeated using methods related to Whitham's theory of wave hierarchies, which brings out the physically relevant parameters in a much clearer way than in the original analysis. It is also used for the stability of non-equilibrium states and we show that for gas cooling behind a shock, the usual analysis is only quantitatively valid for shocks that are just able to trigger a transition to the cold phase. A magnetic field can readily be included and we show that this does not change the stability criteria. By considering steady shock solutions, we show that almost all plausible initial conditions lead to a magnetically dominated state on the unstable part of the equilibrium curve. These results are used to analyse numerical calculations of perturbed steady shock solutions and of shocks interacting with a warm cloud.

[19]  arXiv:2001.01093 [pdf, other]

Title: Testing the solar activity paradigm in the context of exoplanet transits

Authors: Carolus J. Schrijver

Comments: Accepted for publication in the Astrophysical Journal

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

Transits of exoplanets across cool stars contain blended information about structures on the stellar surface and about the planetary body and atmosphere. To advance understanding of how this information is entangled, a surface-flux transport code, based on observed properties of the Sun's magnetic field, is used to simulate the appearance of hypothetical stellar photospheres from the visible near 4000 Angstrom to the near-IR at 1.6 micron, by mapping intensities characteristic of faculae and spots onto stellar disks. Stellar appearances are computed for a Sun-like star of solar activity up to a star with mean magnetic flux density ~30 times higher. Simulated transit signals for a Jupiter-class planet are compared with observations. This (1) suggests that the solar paradigm is consistent with observations for stars throughout the activity range explored provided that infrequent large active regions with fluxes up to $\sim 3\times 10^{23}$ Mx are included in the emergence spectrum, (2) quantitatively confirms that for such a model, faculae brighten relatively inactive stars while starspots dim more active stars, (3) suggests that large starspots inferred from transits of active stars are consistent with clusters of more compact spots seen in the model runs, (4) that wavelength-dependent transit-depth effects caused by stellar magnetic activity for the range of activity and the planetary diameter studied here can introduce apparent changes in the inferred exoplanetary radii across wavelengths from a few hundred to a few thousand kilometers, increasing with activity, and (5) that activity-modulated distortions of broadband stellar radiance across the visible to near-IR spectrum can reach several percent.

[20]  arXiv:2001.01105 [pdf, other]

Title: Long term γ -ray variability of blazars

Authors: Bhoomika Rajput, C.S.Stalin, Suvendu Rakshit

Comments: 8 pages, 14 figures, Accepted for publication in A&A

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

We used the data from the Fermi Gamma-ray Space Telescope to characterise the {\gamma}-ray flux variability of blazars on month-like time scales. Our sample consists of 1120 blazars of which 481 are flat spectrum radio quasars (FSRQs) and 639 are BL Lac objects (BL Lacs). We generated monthly binned light curves of our sample for a period of approximately nine years from 2008 August to 2017 December and quantified variability by using excess variance (F_var). On month-like time scales, 371/481 FSRQs are variable ( 80%), while only about 50% (304/639) of BL Lacs are variable. This suggests that FSRQs are more variable than BL Lac objects. We find a mean F_var of 0.55 +/- 0.33 and 0.47 +/- 0.29 for FSRQs and BL Lacs respectively. Large F_var in FSRQs is also confirmed from the analysis of the ensemble structure function. By Dividing our sample of blazars based on the position of the synchrotron peak in their broad-band spectral energy distribution, we find that the low synchrotron peaked (LSP) sources have the largest mean F_var value of 0.54 +/- 0.32 while the intermediate synchrotron peaked (ISP) and high synchrotron peaked (HSP) sources have mean F_var values of 0.45 +/- 0.25 and 0.47 +/- 0.33 respectively. On month-like time scales, we find FSRQs to show a high duty cycle (DC) of variability of 66% relative to BL Lacs that show a DC of 36%. We find that both the F_var and time scale of variability ({\tau}) do not correlate with the black hole mass. We note that F_var is found to be weakly correlated with Doppler factor ({\delta}) and {\tau} is also weakly correlated with {\delta}. Most of the sources in our sample have {\tau} of the order of days, which might be related to processes in the jet. We find marginal difference in the distribution of {\tau} between FSRQs and BL Lacs.

[21]  arXiv:2001.01106 [pdf, other]

Title: Long-term evolution of the Galilean satellites: the capture of Callisto into resonance

Authors: G. Lari, M. Saillenfest, M. Fenucci

Comments: 17 pages, 10 figures. Submitted to Astronomy & Astrophysics

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

Context. The strong tidal dissipation in the couple Jupiter-Io is spread to all the moons involved in the Laplace resonance (Io, Europa, and Ganymede), leading to a migration of their orbits.
Aims. We aim to characterize the behavior of the Galilean satellites over the Solar System lifetime and to quantify the stability of the Laplace resonance. Since tidal dissipation makes possible the exit from the current resonances or capture into new ones, we investigate the capture of Callisto into resonance.
Methods. We perform hundreds of propagations using an improved version of a recent semi-analytical model. As Ganymede moves outwards, it approaches the 2:1 resonance with Callisto, inducing a temporary chaotic motion in the system. For this reason, we draw a statistical picture of the outcome of the resonant encounter.
Results. The system can settle into two distinct outcomes: A) a chain of three 2:1 two-body resonances (Io-Europa, Europa-Ganymede and Ganymede-Callisto), or B) a resonant chain involving the 2:1 two-body resonance Io-Europa plus at least one pure 4:2:1 three-body resonance, most frequently between Europa, Ganymede and Callisto. In case A (56\% of the simulations), the Laplace resonance is always preserved and the eccentricities remain confined to small values below 0.01. In case B (44\% of the simulations), the Laplace resonance is generally disrupted and the eccentricities of Ganymede and Callisto can increase up to about 0.1, making this configuration unstable and driving the system into new resonances.
Conclusion. From our results, the capture of Callisto into resonance appears to be extremely likely (100\% of our simulations). Assuming the most recent estimates of the dissipation between Io and Jupiter, the resonant encounter happens at about 1.5 Gyrs from now. Therefore, the stability of the Laplace resonance is guaranteed at least up to about 1.5 Gyrs.

[22]  arXiv:2001.01107 [pdf, other]

Title: Gaia RR Lyrae Stars in Nearby Ultra-Faint Dwarf Satellite Galaxies

Authors: A. Katherina Vivas, Clara Martínez-Vázquez, Alistair Walker (CTIO, NSF's National Optical-Infrared Astronomy Research Laboratory)

Comments: Accepted for publication in ApJSS

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

We search for RR Lyrae stars in 27 nearby ($<100$ kpc) ultra-faint dwarf satellite galaxies using the Gaia DR2 catalog of RR Lyrae stars. Based on proper motions, magnitudes and location on the sky, we associate 47 Gaia RR Lyrae stars to 14 different satellites. Distances based on RR Lyrae stars are provided for those galaxies. We have identified RR Lyrae stars for the first time in the Tucana II dwarf galaxy, and find additional members in Ursa Major II, Coma Berenices, Hydrus I, Bootes I and Bootes III. In addition we have identified candidate extra-tidal RR Lyrae stars in six galaxies which suggest they may be undergoing tidal disruption. We found 10 galaxies have no RR Lyrae stars neither in Gaia nor in the literature. However, given the known completeness of Gaia DR2 we cannot conclude these galaxies indeed lack variable stars of this type.

[23]  arXiv:2001.01135 [pdf, other]

Title: Lensing efficiency for gravitational wave mergers

Authors: O. Contigiani

Comments: 6 pages, 4 figures. Accepted for publication in MNRAS

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

We gain insight into the effects of gravitational lensing on the estimated distribution of merging binaries observed through gravitational waves. We quantify the efficiency of magnification for gravitational wave events in the geometric optics limit, and we compare it to the electromagnetic case by making minimal assumptions about the distribution of intrinsic properties for the source population. We show that lensing effects leave a recognizable signature on the observed rates, and that they can be prominent only in the presence of an extremely steep mass function (or redshift evolution) and mainly at low inferred redshifts. We conclude that gravitational magnification does not represent a significant systematic for gravitational wave merger studies in the LIGO-Virgo era.

[24]  arXiv:2001.01150 [pdf, ps, other]

Title: The properties of prompt emission in short GRBs with extended emission observed by {\em Fermi}/GBM

Authors: Lin Lan, Hou-Jun Lü, Jun Shen, Jared Rice, Long Li, En-Wei Liang

Comments: 12 pages, 6 figures, and 1 table. Accepted for publication in MNRAS

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

Short GRBs with extended emission (EE) that are composed initially of a short-hard spike and followed by a long-lasting EE, are thought to be classified as a subsection of short GRBs. The narrow energy band available during the {\em Swift} era combined with a lack of spectral information prevented discovery of the intrinsic properties of those events. In this paper, we performed a systematic search of short GRBs with EE by using all available {\em Fermi}/GBM data. The search identified 26 GBM-detected short GRBs with EE that are similar to GRB 060614 observed by {\em Swift}/BAT. We focus on investigating the spectral and temporal properties for both the hard spike and the EE components of all 26 GRBs, and explore differences and possible correlations between them. We find that while the peak energy ($E_{\rm p}$) of the hard spikes is a little bit harder than that of the EE, but their fluences are comparable. The harder $E_{\rm p}$ seems to correspond to a larger fluence and peak flux with a large scatter for both the hard spike and EE components. Moreover, the $E_{\rm p}$ of both the hard spikes and EE are compared to other short GRBs. Finally, we also compare the properties of GRB 170817A with those short GRBs with EE and find no significant statistical differences between them. We find that GRB 170817A has the lowest $E_{\rm p}$, likely because it was off-axis.

[25]  arXiv:2001.01160 [pdf, other]

Title: The splashback radius of optically selected clusters with Subaru HSC Second Public Data Release

Authors: Ryoma Murata, Tomomi Sunayama, Masamune Oguri, Surhud More, Atsushi J. Nishizawa, Takahiro Nishimichi, Ken Osato

Comments: 32 pages, 13 figures, 6 tables. Submitted to PASJ; abstract abridged to meet arXiv requirements

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

Recent constraints on the splashback radius around optically selected galaxy clusters from the redMaPPer cluster-finding algorithm in the literature have shown that the observed splashback radius is $\sim 20\%$ smaller than that predicted by {\it N}-body simulations. We present analyses on the splashback features around $\sim 3000$ optically selected galaxy clusters detected by the independent cluster-finding algorithm CAMIRA over a wide redshift range of $0.1<z_{\rm cl}<1.0$ from the second public data release of the Hyper Suprime-Cam (HSC) Subaru Strategic Program covering $\sim 427~{\rm deg}^2$ for the cluster catalog. We detect the splashback feature from the projected cross-correlation measurements between the clusters and photometric galaxies over the wide redshift range, including for high redshift clusters at $0.7<z_{\rm cl}<1.0$, thanks to deep HSC images. We find that constraints from red galaxy populations only are more precise than those without any color cut, leading to $1\sigma$ precisions of $\sim 15\%$ at $0.4<z_{\rm cl}<0.7$ and $0.7<z_{\rm cl}<1.0$. These constraints are more consistent with the model predictions ($\lesssim 1\sigma$) than their $20\%$ smaller values as suggested by the previous studies with the redMaPPer ($\sim 2\sigma$). We also investigate selection effects of the optical cluster-finding algorithms on the observed splashback features by creating mock galaxy catalogs from a halo occupation distribution model, and find that such effects to be sub-dominant for the CAMIRA cluster-finding algorithm. We also find that the redMaPPer-like cluster-finding algorithm induces a smaller inferred splashback radius in our mock catalog, especially at lower richness, which can well explain the smaller splashback radii in the literature. In contrast, these biases are significantly reduced when increasing its aperture size.

[26]  arXiv:2001.01186 [pdf, ps, other]

Title: Constraints on the intergalactic magnetic field from $γ$-ray observations of GRB 190114C

Authors: Ze-Rui Wang, Shao-Qiang Xi, Ruo-Yu Liu, Rui Xue, Xiang-Yu Wang

Comments: 5 pages, 4 figures, submitted to PRD

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

Very high energy photons from cosmological gamma-ray bursts (GRBs) are expected to interact with extragalactic background light (EBL) and produce electron-positron pairs when they propagate through intergalactic medium (IGM). These relativistic pairs will then up-scatter cosmic microwave background (CMB) photons and emit secondary GeV emission. Meanwhile, the motion of these pairs are deflected by intergalactic magnetic field (IGMF), so the secondary GeV photons arrive later than the primary emission. It has been suggested that the properties of the secondary GeV emission can be used to constrain IGMF. Recently, TeV gamma-ray emission has been detected, for the first time, from a GRB (GRB 190114C) by the MAGIC telescope and its steep ${\rm \gamma-ray}$ spectrum shows a clear evidence of absorption by EBL. We then constrain the IGMF with the GeV flux limit obtained from the $Fermi$-LAT observations. We find a limit of $>10^{-19.5}$ G for the coherence length of $\lambda \leq 1$ Mpc. Although this limit is weaker than that obtained by using blazars, it represents the first limit from ${\rm \gamma-ray}$ observations of GRBs, which provides an independent constraint on IGMF. We also find that, for transient gamma-ray sources, one can choose a favorable time window to search for the echo emission at a particular energy.

[27]  arXiv:2001.01203 [pdf, other]

Title: Measuring the Etalon Quality of the GREGOR Fabry-Pérot Interferometer

Authors: Meetu Verma, Carsten Denker

Comments: 18 pages, 9 figures, 4 tables

Journal-ref: J. Astron. Telesc. Instrum. Syst. 6(1), 015001 (2020)

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

Imaging spectropolarimetry is an important observational tool in solar physics because of fast-cadence spectral scans with high-spectral resolution, large field-of-view, and its inherent suitability for post-facto image restoration. Fabry-P\'erot etalons are the key optical elements of these instruments. Their optical quality critically defines the instrument's performance. The two etalons of the GREGOR Fabry-P\'erot Interferometer (GFPI) were used for more than 10~years, raising questions about the potential deterioration of etalons coatings. We present an assessment of the etalons optical quality, describe the inspection method based on Zernike polynomials, discuss the field dependence of the finesse and its consequences for instrument design, and investigate the impact of the measurement technique to achieve plate parallelism. We find that extended exposure to sunlight affects the etalon coatings, i.e., lowering the peak transmission and leaving an imprint of the pupil of the GREGOR solar telescope on the etalon that is directly exposed to sunlight. The finesse of both etalons, however, remains high so that the impact on imaging spectropolarimetry is negligible.

[28]  arXiv:2001.01205 [pdf]

Title: Migration of giant gaseous clumps and structure of the outer Solar system

Authors: V. V. Emel'yanenko

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

New data on the distribution of distant trans-Neptunian objects and on the properties of comets indicate the importance of dynamical processes in the outer part of the protoplanetary disk in the formation of the observed structure of the Solar system. In this paper, we examined the possible action of giant gaseous clumps, resulting from gravitational instability and fragmentation of circumstellar disks, on the orbital distribution of the population of small bodies in the outer Solar system. Basically, we studied those features of migration and gravitational interaction of giant clumps that were found previously by Vorobyov and Elbakyan (2018). Our modeling showed that the main features of the distribution of small bodies resulting from the gravitational influence of giant clumps are consistent with the observed orbital distribution of distant trans-Neptunian objects. The studied dynamical process associated with a single giant clump is very short-time event (no more than several tens of thousands of years). The main factor affecting the orbital distribution of small bodies is close encounters with giant clumps. A significant part of small bodies (comets) is very quickly transferred to distant orbits with large eccentricities, which allows them to avoid mutual collisions.

[29]  arXiv:2001.01231 [pdf, other]

Title: Galactic Conformity in both Star-formation and Morphological Properties

Authors: Justin A. Otter, Karen L. Masters, Brooke Simmons, Chris J. Lintott

Comments: Accepted in MNRAS

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

We investigate one-halo galactic conformity (the tendency for satellite galaxies to mirror the properties of their central) in both star-formation and morphology using a sample of 8230 galaxies in 1266 groups with photometry and spectroscopy from the Sloan Digital Sky Survey, morphologies from Galaxy Zoo and group memberships as determined by Yang et al. This is the first paper to investigate galactic conformity in both star-formation and visual morphology properties separately. We find that the signal of galactic conformity is present at low significance in both star-formation and visual morphological properties, however it is stronger in star-formation properties. Over the entire halo mass range we find that groups with star-forming (spiral) centrals have, on average, a fraction 0.18+-0.08 (0.08+-0.06) more star-forming (spiral) satellites than groups with passive (early-type) centrals at a similar halo mass. We also consider conformity in groups with four types of central: passive early-types, star-forming spirals, passive spirals and star-forming early-types (which are very rarely centrals), finding that the signal of morphological conformity is strongest around passive centrals regardless of morphology; although blue spiral centrals are also more likely than average to have blue spiral satellites. We interpret these observations of the relative size of the conformity signal as supporting a scenario where star-formation properties are relatively easily changed, while morphology changes less often/more slowly for galaxies in the group environment.

[30]  arXiv:2001.01241 [pdf, ps, other]

Title: Gravitational wave spectrum from kinks on infinite cosmic superstrings with Y-junctions

Authors: Yuka Matsui, Koichiro Horiguchi, Daisuke Nitta, Sachiko Kuroyanagi

Comments: 26 pages, 36 figures

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

We calculate the gravitational wave (GW) background spectra from kink propagation and kink-kink collisions on infinite cosmic superstrings. We take into account two characteristics of the cosmic superstring network: a small reconnection probability and Y-junctions. First, a small reconnection probability increases the number of infinite strings inside the horizon and enhances the kink production, which leads a larger amplitude of the GW background. Second, a kink going through a Y-junction transforms into three daughter kinks. In this way, the existence of Y-junctions also increases the number of kinks on cosmic superstrings. However, at the same time, it smooths out the sharpness of kinks rapidly and reduces the number of sharp kinks, which are responsible for the emissions of strong GW bursts. We compute the number distribution of kinks as a function of the sharpness by taking into account the above two effects, and translate it to the amplitude of the GW background spectra. We first investigate the case of the string network with equal string tensions, and find that the effect of Y-junctions to smooth out kink sharpness dominates that of the enhancement of the kink number by a small reconnection probability, and the GW amplitude turns out to be smaller than the ordinary cosmic string case. On the other hand, for non-equal string tensions, we find that there is a parameter space where the GW amplitude is slightly enhanced by the effect of a small reconnection probability.

[31]  arXiv:2001.01250 [pdf, ps, other]

Title: Longitudinal filament oscillations enhanced by two C-class flares

Authors: Q. M. Zhang, J. H. Guo, K. V. Tam, A. A. Xu

Comments: 9 pages, 16 figures, 3 tables, accepted for publication in A&A

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

In this paper, we report the multiwavelength observations of a very long filament in active region (AR) 11112 on 2010 October 18. The filament was composed of two parts, the eastern part (EP) and western part (WP). We focus on longitudinal oscillations of the EP, which were enhanced by two homologous C-class flares in the same AR. The C1.3 flare was confined without a CME. Both EP and WP of the filament were slightly disturbed and survived the flare. After 5 hrs, eruption of the WP generated a C2.6 flare and a narrow, jet-like CME. Three oscillating threads (thd$_a$, thd$_b$, thd$_c$) are obviously identified in the EP and their oscillations are naturally divided into three phases by the two flares. The initial amplitude ranges from 1.6 to 30 Mm with a mean value of $\sim$14 Mm. The period ranges from 34 to 73 minutes with a mean value of $\sim$53 minutes. The curvature radii of the magnetic dips are estimated to be 29 to 133 Mm with a mean value of $\sim$74 Mm. The damping times ranges from $\sim$62 to $\sim$96 minutes with a mean value of $\sim$82 minutes. The value of $\tau/P$ is between 1.2 and 1.8. For thd$_a$ in the EP, the amplitudes were enhanced by the two flares from 6.1 Mm to 6.8 Mm after the C1.3 flare and further to 21.4 Mm after the C2.6 flare. The period variation as a result of perturbation from the flares was within 20\%. The attenuation became faster after the C2.6 flare. To the best of our knowledge, this is the first report of large-amplitude, longitudinal filament oscillations enhanced by flares. Numerical simulations reproduce the oscillations of thd$_a$ very well. The simulated amplitudes and periods are close to the observed values, while the damping time in the last phase is longer, implying additional mechanisms should be taken into account apart from radiative loss.

[32]  arXiv:2001.01292 [pdf]

Title: Analysis of some Semi-Detached systems observed by TESS

Authors: Fahri Alicavus

Comments: a contribution to the proceedings of the Turkish Physical Society 35th International Physics Congress, 4 pages, 2 figures, 2 tables

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

Semi-Detached binary stars are very important systems for the precise determination of astrophysical parameters and the analysis of mass transfer and loss mechanisms between the components. In this study, the light curve analysis of some semi-detached systems (RV Pic and AS Eri), which light changes are obtained by the Transiting Exoplanet Survey Satellite (TESS), was performed. The astrophysical parameters of the systems were obtained. In addition, oscillational properties of the systems were investigated, and the mass transfer and the loss amount of such stars are discussed and compared with observational data.

[33]  arXiv:2001.01299 [pdf, other]

Title: The evolutionary track of H/He envelope in the observed population of sub-Neptunes and Super-Earths planets

Authors: Raissa Estrela, Mark Swain, Akash Gupta, Christophe Sotin, Adriana Valio

Comments: 8 pages, 8 figures; submitted to ApJ

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

The observational detection of a localized reduction in the small planet occurrence rate, sometimes termed a "gap", is an exciting discovery because of the implications for planet evolutionary history. This gap appears to define a transition region in which sub-Neptune planets are believed to have lost their H/He envelope, potentially by photoevaporation or core powered mass loss, and have thus been transformed into bare cores terrestrial planets. Here we investigate the transition between sub-Neptunes and super-Earths by using envelope evolution models of the H/He envelope together with the mass-radius diagram and a photoevaporation model. We find that photoevaporation cannot explain the loss of the H/He envelope if the super-Earths and sub-Neptunes have the same core mass distribution. We explore the possibility that these planets families have different core mass and find that the primordial envelope fractions of the strongly irradiated super-Earths and the sub-Neptunes at an age of 100Myr is ~12% of their original mass. This agreement suggests that these two groups are part of the same primordial, parent population. Our analysis also shows that sub-Neptunes with R < 3.5 R$<$3.5 R$_{\oplus}$ typically lose ~70% of their primordial envelope.

[34]  arXiv:2001.01336 [pdf, other]

Title: Modeling the upper kHz QPOs of 4U 1728-34 with X-ray reverberation

Authors: Benjamin M. Coughenour, Edward M. Cackett, Philippe Peille, Jon S. Troyer

Comments: Accepted for publication in ApJ. 16 pages, 7 figures

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

While kilohertz quasi-periodic oscillations (kHz QPOs) have been well studied for decades since their initial discovery, the cause of these signals remains unknown, as no model has been able to accurately predict all of their spectral and timing properties. Separately, X-ray reverberation lags have been detected in AGN and stellar-mass black hole binaries, and reverberation may be expected to occur in neutron star systems as well, producing lags of the same amplitude as the lags measured of the kHz QPOs. Furthermore, the detection of a relativistically reflected Fe K line in the time-averaged spectra of many neutron star systems provides an additional motivation for testing reverberation. While it has been shown that the lag-energy properties of the lower kHz QPOs are unlikely to be produced by X-ray reverberation, the upper kHz QPOs have not yet been explored. We therefore model the upper kHz QPO lag-energy spectra using relativistic ray-tracing functions and apply them to archival RXTE data on 4U 1728-34 where upper kHz QPOs have been detected. By modeling the time-averaged spectra in which upper kHz QPOs had been significantly detected, we determine the reflected flux fraction across all energies and produce a model for the lag-energy spectra from X-ray reverberation. We explore the dependence of the modeled lag properties on several different types of reflection models, but are unable to successfully reproduce the measured lags of 4U 1728-34. We conclude that reverberation alone does not explain the measured time lags detected in upper kHz QPOs.

[35]  arXiv:2001.01338 [pdf, other]

Title: Detectability of Molecular Signatures on TRAPPIST-1e through Transmission Spectroscopy Simulated for Future Space-Based Observatories

Authors: Daria Pidhorodetska, Thomas Fauchez, Geronimo Villanueva, Shawn Domagal-Goldman

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

As discoveries of terrestrial, Earth-sized exoplanets that lie within the habitable zone of their host stars continue to occur at increasing rates, efforts have began to shift from the detection of these worlds to the characterization of their atmospheres through transit spectroscopy. While the detection of molecular signatures can provide an indication of the presence of an atmosphere, Earth-like exoplanets create an exciting opportunity to further characterize these atmospheres by searching for biosignatures that may indicate evidence of past or present life. To date, detection methods have focused on promising targets that orbit M-dwarf stars, such as TRAPPIST-1e, that have a rocky composition and lie within the habitable zone of their host star. While JWST will provide new insights on the atmospheric compositions of these exoplanets, terrestrial planets that fall in the habitable zone of close-in systems will continue to pose challenges in spectroscopy. Herein, we use a Global Climate Model (GCM), a photochemical model, and a radiative transfer suite to simulate an atmosphere on TRAPPIST-1e that assumes the boundary conditions of modern Earth. The detectability of biosignatures on such an atmosphere via transmission spectroscopy is modeled for JWST, where mission concepts such as LUVOIR, HabEx, and Origins are used to compare potential capabilities for the distant future. Despite the drastic increase of aperture size and instrument sensitivity for future observatories, we show that only CO2 would be detectable in transmission spectroscopy for such an atmosphere on these planets, as the presence of clouds and their impacts on scale height strongly limits their molecular detectability. In such a case, the synergy between space- and ground-based spectroscopy may be essential in order to overcome these difficulties.

[36]  arXiv:2001.01361 [pdf, other]

Title: Sensitive Probing of Exoplanetary Oxygen via Mid Infrared Collisional Absorption

Authors: Thomas J. Fauchez, Geronimo L. Villanueva, Edward W. Schwieterman, Martin Turbet, Giada Arney, Daria Pidhorodetska, Ravi K. Kopparapu, Avi Mandell, Shawn D. Domagal-Goldman

Comments: Published in Nature Astronomy

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

The collision-induced fundamental vibration-rotation band at 6.4 um is the most significant absorption feature from O2 in the infrared (Timofeyev and Tonkov, 1978; Rinslandet al., 1982, 1989), yet it has not been previously incorporated into exoplanet spectral analyses for several reasons. Either CIAs were not included or incomplete/obsolete CIA databases were used. Also, the current version of HITRAN does not include CIAs at 6.4 um with other collision partners (O2-X). We include O2-X CIA features in our transmission spectroscopy simulations by parameterizing the 6.4 um O2-N2 CIA based on Rinsland et al.(1989) and the O2-CO2 CIA based on Baranov et al. (2004). Here we report that the O2-X CIA may be the most detectable O2 feature for transit observations. For a potentialTRAPPIST-1e analogue system within 5 pc of the Sun, it could be the only O2 detectable signature with JWST (using MIRI LRS) for a modern Earth-like cloudy atmosphere with biological quantities of O2. Also, we show that the 6.4 um O2-X CIA would be prominent for O2-rich desiccated atmospheres (Luger and Barnes, 2015) and could be detectable with JWST in just a few transits. For systems beyond 5 pc, this feature could therefore be a powerful discriminator of uninhabited planets with non-biological "false positive" O2 in their atmospheres - as they would only be detectable at those higher O2 pressures.

[37]  arXiv:2001.01369 [pdf, other]

Title: The Roles of Mass and Environment in the Quenching of Galaxies II

Authors: E. Contini, Q. Gu, X. Ge, J. Rhee, S.K. Yi, X. Kang

Comments: 13 pages, 8 figures, accepted for publication in ApJ

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

We take advantage of an analytic model of galaxy formation coupled to the merger tree of an N-body simulation to study the roles of environment and stellar mass in the quenching of galaxies. The model has been originally set in order to provide the observed evolution of the stellar mass function as well as reasonable predictions of the star formation rate-stellar mass relation, from high redshift to the present time. We analyse the stellar mass and environmental quenching efficiencies and their dependence on stellar mass, halo mass (taken as a proxy for the environment) and redshift. Our analysis shows that the two quenching efficiencies are redshift, stellar and halo mass dependent, and that the halo mass is also a good proxy for the environment. The environmental quenching increases with decreasing redshift and is inefficient below $\log M_* \sim 9.5$, reaches the maximum value at $\log M_* \sim 10.5$, and decreases again becoming poorly efficient at very high stellar mass ($\log M_* \gtrsim 11.5$). Central and satellites galaxies are mass quenched differently: for the former, the quenching efficiency depends very weakly on redshift, but strongly on stellar mass; for the latter, it strongly depends on both stellar mass and redshift in the range $10\lesssim \log M_* \lesssim 11$. According to the most recent observational results, we find that the two quenching efficiencies are not separable: intermediate mass galaxies are enviromental quenched faster, as well as intermediate/massive galaxies in more massive haloes. At stellar masses lower than $\log M_* \lesssim 9.5$ both quenching mechanisms become inefficient, independently of the redshift.

[38]  arXiv:2001.01372 [pdf, other]

Title: Applying Information Theory to Design Optimal Filters for Photometric Redshifts

Authors: J. Bryce Kalmbach, Jacob T. VanderPlas, Andrew J. Connolly

Comments: 29 pages, 17 figures, accepted to ApJ

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Information Theory (cs.IT); Applications (stat.AP)

In this paper we apply ideas from information theory to create a method for the design of optimal filters for photometric redshift estimation. We show the method applied to a series of simple example filters in order to motivate an intuition for how photometric redshift estimators respond to the properties of photometric passbands. We then design a realistic set of six filters covering optical wavelengths that optimize photometric redshifts for $z <= 2.3$ and $i < 25.3$. We create a simulated catalog for these optimal filters and use our filters with a photometric redshift estimation code to show that we can improve the standard deviation of the photometric redshift error by 7.1% overall and improve outliers 9.9% over the standard filters proposed for the Large Synoptic Survey Telescope (LSST). We compare features of our optimal filters to LSST and find that the LSST filters incorporate key features for optimal photometric redshift estimation. Finally, we describe how information theory can be applied to a range of optimization problems in astronomy.

[39]  arXiv:2001.01390 [pdf, ps, other]

Title: On the Secondary's Rotation in Synchronous Binary Asteroid

Authors: Haishuo Wang, Xiyun Hou

Comments: 19 figures. It has now been accepted for publication in Monthly Notices of the Royal Astronomical Society Main Journal but not been published

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

This paper studies the secondary's rotation in a synchronous binary asteroid system in which the secondary enters the 1:1 spin-orbit resonance. The model used is the planar full two-body problem composed of a spherical primary plus a tri-axial ellipsoid secondary. Compared with classical spin-orbit work, there are two differences: (1) Influence on the mutual orbit from the secondary's rotation is considered; (2) Instead of the Hamiltonian approach, the approach of periodic orbits is adopted. Our studies find: (1) Genealogy of the two families of periodic orbits is same as that of the families around triangular libration points in the restricted three-body problem. That is, the long-period family terminates onto a short-period orbit travelling N times; (2) In the limiting case where the secondary's mass is negligible, our results can be reduced to the classical spin-orbit theory, by equating the long-period orbit with the free libration, and by equating the short-period orbit with the forced libration caused by orbit eccentricity. However, the two models show obvious differences when the secondary's mass is non-negligible. (3) By studying the stability of periodic orbits, for a specific binary asteroid system, we are able to obtain the maximum libration amplitude of the secondary (which is usually less than 90 degree), and the maximum mutual orbit eccentricity which does not break the secondary's synchronous state. We also find the anti-correlation between the secondary's libration amplitude and the orbit eccentricity. The (65803) Didymos system is taken as an example to show the results.

[40]  arXiv:2001.01399 [pdf, other]

Title: Applying Noether's theorem to matter in the Milky Way: evidence for external perturbations and non-steady-state effects from Gaia Data Release 2

Authors: Susan Gardner, Austin Hinkel, Brian Yanny

Comments: 15 pages, 8 figure panels, AASTeX, accepted for publication in ApJ

Subjects: Astrophysics of Galaxies (astro-ph.GA); High Energy Physics - Phenomenology (hep-ph); Nuclear Theory (nucl-th)

We apply Noether's theorem to observations of main-sequence stars from the Gaia Data Release 2 archive to probe the matter distribution function of the Galaxy. That is, we examine the axial symmetry of stars at vertical heights $z$, $0.2 \le |z| \le 3$ kpc, to probe the quality of the angular momentum $L_z$ as an integral of motion. The failure of this symmetry test would speak to a Milky Way, in both its visible and dark matter, that is not isolated and/or not in steady state. The left-right symmetry-breaking pattern we have observed, north and south, reveals both effects, with a measured deviation from symmetry of typically 0.5%. We show that a prolate form of the gravitational distortion of the Milky Way by the Large Magellanic Cloud, determined from fits to the Orphan stream by Erkal et al., 2019, is compatible with the size and sign of the axial-symmetry-breaking effects we have discovered in our sample of up to 14.4 million main-sequence stars, speaking to a distortion of an emergent, rather than static, nature.

[41]  arXiv:2001.01407 [pdf, other]

Title: Gravitational waves from binary black holes as probes of the structure formation history

Authors: Tomohiro Nakama

Comments: 12 pages, 2 figures

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

Gravitational-wave detectors on earth have detected gravitational waves from merging compact objects in the local Universe. In future we will detect gravitational waves from higher-redshift sources, which trace the high-redshift structure formation history. That is, by observing high-redshift gravitational-wave events we will be able to probe structure formation history. This will provide additional insight into the early Universe when primordial fluctuations are generated and also into the nature of dark matter.

[42]  arXiv:2001.01409 [pdf, other]

Title: Seventeen Tidal Disruption Events from the First Half of ZTF Survey Observations: Entering a New Era of Population Studies

Authors: Sjoert van Velzen, Suvi Gezari, Erica Hammerstein, Nathaniel Roth, Sara Frederick, Charlotte Ward, Tiara Hung, S. Bradley Cenko, Robert Stein, Daniel A. Perley, Kirsty Taggart, Jesper Sollerman, Igor Andreoni, Eric C. Bellm, Valery Brinnel, Kishalay De, Richard Dekany, Michael Feeney, Ryan J. Foley, Christoffer Fremling, Matteo Giomi, V. Zach Golkhou, Anna. Y. Q. Ho, Mansi M. Kasliwal, Charles D. Kilpatrick, Shrinivas R. Kulkarni, Thomas Kupfer, Russ R. Laher, Ashish Mahabal, Frank J. Masci, Jakob Nordin, Reed Riddle, Ben Rusholme, Yashvi Sharma, Jakob van Santen, David L. Shupe, Maayane T. Soumagnac

Comments: 30 pages, 18 figures, 8 tables, to be submitted to ApJ, comments welcome

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

While tidal disruption events (TDEs) have long been heralded as laboratories for the study of quiescent black holes, the small number of known TDEs and uncertainties in their emission mechanism have hindered progress towards this promise. Here present 17 new TDEs that have been detected recently by the Zwicky Transient Facility along with Swift UV and X-ray follow-up observations. Our homogeneous analysis of the optical/UV light curves, including 22 previously known TDEs from the literature, reveals a clean separation of light curve properties with spectroscopic class. The TDEs with Bowen fluorescence features in their optical spectra have smaller blackbody radii, as well as longer rise times and higher disruption rates compared to the rest of the sample. The Bowen fluorescence mechanism requires a high density which can be reached at smaller radii, which in turn yields longer diffusion timescales. Thus, the difference in rise times suggests the pre-peak TDE light curves are governed not by the fallback timescale, but instead by the diffusion of photons through the tidal debris. The small subset of TDEs that show only helium emission lines in their spectra have the longest rise times, the highest luminosities and the lowest rates. We also report, for the first time, the detection of soft X-ray flares from a TDE on day timescales. Based on the fact the flares peak at a luminosity similar to the optical/UV blackbody luminosity, we attribute them to brief glimpses through a reprocessing layer that otherwise obscures the inner accretion flow.

[43]  arXiv:2001.01411 [pdf, other]

Title: Listening to the heartbeat: Tidal Asteroseismology in action

Authors: Zhao Guo

Comments: 6 pages, 4 figures. Invited introduction for the BRITE Vienna conference, Stars and their variability observed from space, August 2019

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

We briefly review the current status of the study of tidally excited oscillations (TEOs) in heartbeat binary stars. Particular attention is paid to correctly extracting the TEOs when the Fourier spectrum also contains other types of pulsations and variabilities. We then focus on the theoretical modeling of the TEO amplitudes and phases. Pulsation amplitude can be modeled by a statistical approach, and pulsation phases can help to identify the azimuthal number m of pulsation modes. We verify the results by an ensemble study of ten systems. We discuss some future prospects, including the secular evolution and the non-linear effect of TEOs.

[44]  arXiv:2001.01420 [pdf, other]

Title: Are Faint Supernovae Responsible for Carbon-Enhanced Metal-Poor Stars?

Authors: Yutaka Komiya, Takuma Suda, Shimako Yamada, Masayuki Y. Fujimoto

Comments: 17 pages, 19 figures, accepted for publication in the Astrophysical Journal

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

Mixing and fallback models in faint supernova models are supposed to reproduce the abundance patterns of observed carbon-enhanced metal-poor (CEMP) stars in the Galactic halo. A fine tuning of the model parameters for individual stars is required to reproduce the observed ratios of carbon to iron. We focus on extremely metal-poor stars formed out of the ejecta from the mixing and fallback models using a chemical evolution model. Our chemical evolution models take into account the contribution of individual stars to chemical enrichment in host halos together with their evolution in the context of the hierarchical clustering. Parametrized models of mixing and fallback models for Pop. III faint supernovae are implemented in the chemical evolution models with merger trees to reproduce the observed CEMP stars. A variety of choices for model parameters on star formation and metal-pollution by faint supernovae is unable to reproduce the observed stars with [Fe/H] < -4 and [C/H] > -2, which are the majority of CEMP stars among the lowest metallicity stars. Only possible solution is to form stars from small ejecta mass, which produces an inconsistent metallicity distribution function. We conclude that not all the CEMP stars are explicable by the mixing and fallback models. We also tested the contribution of binary mass transfers from AGB stars that are also supposed to reproduce the abundances of known CEMP stars. This model reasonably reproduces the distribution of carbon and iron abundances simultaneously only if we assume that long-period binaries are favored at [Fe/H] < -3.5.

[45]  arXiv:2001.01438 [pdf, other]

Title: Earth-Like: An education & outreach tool for exploring the diversity of planets like our own

Authors: Elizabeth J. Tasker (ISAS, JAXA), Kana Ishimaru (Arizona), Nicholas Guttenberg (ELSI), Julien Foriel (Harvard)

Comments: Accepted for publication in the International Journal of Astrobiology (IJA)

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

Earth-Like is an interactive website and twitter bot that allows users to explore changes in the average global surface temperature of an Earth-like planet due to variations in the surface oceans and emerged land coverage, rate of volcanism (degassing), and the level of the received solar radiation. The temperature is calculated using a simple carbon-silicate cycle model to change the level of $\rm CO_2$ in the atmosphere based on the chosen parameters. The model can achieve a temperature range exceeding $-100^\circ$C to $100^\circ$C by varying all three parameters, including freeze-thaw cycles for a planet with our present-day volcanism rate and emerged land fraction situated at the outer edge of the habitable zone. To increase engagement, the planet is visualised by using a neural network to render an animated globe, based on the calculated average surface temperature and chosen values for land fraction and volcanism. The website and bot can be found at earthlike.world and on twitter as @earthlikeworld. Initial feedback via a user survey suggested that Earth-Like is effective at demonstrating that minor changes in planetary properties can strongly impact the surface environment. The goal of the project is to increase understanding of the challenges we face in finding another habitable planet due to the likely diversity of conditions on rocky worlds within our Galaxy.

[46]  arXiv:2001.01450 [pdf, other]

Title: Primordial mass segregation of star clusters: The role of binary stars

Authors: Václav Pavlík

Comments: 5 pages, 2 figures, will be published in Contrib. Astron. Obs. Skalnate Pleso, 2020 (from conference "Universe of Binaries, Binaries in the Universe" in 2019)

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

Observational results of young star-forming regions suggest that star clusters are completely mass segregated at birth. As a star cluster evolves dynamically, these initial conditions are gradually lost. For star clusters with single stars only and a canonical IMF, it has been suggested that traces of these initial conditions vanish at $\tau_{\rm v}$ between 3 and 3.5 half-mass relaxation times. By the means of numerical models, here we investigate the role of the primordial binary population on the loss of primordial mass segregation. We found that $\tau_{\rm v}$ does not seem to depend on the binary star distribution, yielding $3 < \tau_{\rm v} / t_{\rm rh} < 3.5$. We also conclude that the completely mass segregated clusters, even with binaries, are more compatible with the present-day ONC than the non-segregated ones.

[47]  arXiv:2001.01451 [pdf, ps, other]

Title: The VLT-FLAMES Tarantula Survey XXXII. Low-luminosity late O-type stars -- classification, main physical parameters, and silicon abundances

Authors: N. Markova, J. Puls, P. L. Dufton, D. J. Lennon, C. J. Evans, A. de Koter, O. H. Ramirez-Agudelo, H. Sana, J. S. Vink

Comments: 18 pages, 10 figures accepted for publication in A&A

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

Analysis of late O-type stars observed in the Large Magellanic Cloud (LMC) by the VLT-FLAMES Tarantula Survey (VFTS) revealed a discrepancy between the physical properties estimated from model-atmosphere analysis and those expected from their morphological classifications. Here we revisit the analysis of 32 of these puzzling objects using new hydrogen-helium-silicon FASTWIND models and a different fitting approach to re-evaluate their physical properties. Our new analysis confirms that these stars indeed have properties that are typical of late O-type dwarfs. We also present the first estimates of silicon abundances for O-type stars in the 30 Dor clusters NGC 2060 and NGC 2070, with a weighted mean abundance for our sample of 7.05 +/- 0.03. Our values are about 0.20 dex lower than those previously derived for B-type stars in the LMC clusters N 11 and NGC 2004 using TLUSTY models. Various possibilities (e.g. differences in the analysis methods, effects of microturbulence, and real differences between stars in different clusters) were considered to account for these results. We also used our grid of FASTWIND models to reassess the impact of using the Galactic classification criteria for late O-type stars in the LMC by scrutinising their sensitivity to different stellar properties. At the cool edge of the O star regime the HeII 4686/HeI 4713 ratio used to assign luminosity class for Galactic stars can mimic giants or bright giants in the LMC, even for objects with high gravities (log_g > 4.0 dex). We argue that this line ratio is not a reliable luminosity diagnostic for late O-type stars in the LMC, and that the SiIV 4989/HeI4026 ratio is more robust for these types.

[48]  arXiv:2001.01481 [pdf, ps, other]

Title: The Cluster Ages Experiment (CASE). VIII. Age and Distance of the Globular Cluster 47 Tuc from the Analysis of Two Detached Eclipsing Binaries

Authors: I. B. Thompson, A. Udalski, A. Dotter, M. Rozyczka, A. Schwarzenberg-Czerny, W. Pych, Y. Beletsky, G. S. Burley, J. L. Marshall, A. McWilliam, N. Morrell, D. Osip, A. Monson, S. E. Persson, M. K. Szymański, I. Soszyński, R. Poleski, K. Ulaczyk, Ł. Wyrzykowski, S. Kozłowski, P. Mróz, P. Pietrukowicz, J. Skowron

Comments: Accepted by MNRAS

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

We use photometric and spectroscopic observations of the eclipsing binary E32 in the globular cluster 47 Tuc to derive the masses, radii, and luminosities of the component stars. The system has an orbital period of 40.9 d, a markedly eccentric orbit with e = 0.24, and is shown to be a member of or a recent escaper from the cluster. We obtain Mp = 0.862(5) Msun , Rp = 1.183(3) Rsun , Lp = 1.65(5) Lsun for the primary and Ms = 0.827(5) Msun , Rs = 1.004(4) Rsun , Ls = 1.14(4) Lsun for the secondary. Based on these data and on an earlier analysis of the binary V69 in 47 Tuc we measure the distance to the cluster from the distance moduli of the component stars, and, independently, from a color - surface brightness calibration. We obtain 4.55(3) and 4.50(7) kpc, respectively - values compatible within 1 sigma with recent estimates based on Gaia DR2 parallaxes. By comparing the M - R diagram of the two binaries and the color-magnitude diagram of 47 Tuc to Dartmouth model isochrones we estimate the age of the cluster to be 12.0 pm 0.5 Gyr, and the helium abundance of the cluster to be Y approx 0.25.

[49]  arXiv:2001.01482 [pdf, other]

Title: The "Small Bodies: Near and Far" Infrared Database

Authors: Róbert Szakáts, Thomas Müller, Víctor Alí-Lagoa, Gábor Marton, Anikó Farkas-Takáács, Evelin Bányai, Csaba Kiss

Comments: 16 pages, 8 figures, 2 tables

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

In this paper we present the "Small Bodies: Near and Far" Infrared Database, an easy-to-use tool intended to facilitate the modeling of thermal emission of small Solar System bodies. Our database collects thermal emission measurements of small Solar Systems targets that are otherwise available in scattered sources and gives a complete description of the data, with all information necessary to perform direct scientific analyses and without the need to access additional, external resources. This public database contains representative data of asteroid observations of large surveys (e.g. AKARI, IRAS and WISE) as well as a collection of small body observations of infrared space telescopes (e.g. the Herschel Space Observatory) and provides a web interface to access this data (https://ird.konkoly.hu). We also provide an example for the direct application of the database and show how it can be used to estimate the thermal inertia of specific populations, e.g. asteroids within a given size range. We show how different scalings of thermal inertia with heliocentric distance (i.e. temperature) may affect our interpretation of the data and discuss why the widely-used radiative conductivity exponent ($\alpha$=-3/4) might not be adequate in general, as hinted by previous studies.

[50]  arXiv:2001.01484 [pdf, other]

Title: \ce{^{14}N/^{15}N} isotopic ratio in \ce{CH3CN} of Titan's atmosphere measured with ALMA

Authors: Takahiro Iino, Hideo Sagawa, Takashi Tsukagoshi

Comments: To be published in ApJ

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

Each of the nitriles present in the atmosphere of Titan can be expected to exhibit different \ce{^{14}N/^{15}N} values depending on their production processes, primarily because of the various \ce{N2} dissociation processes induced by different sources such as ultraviolet radiation, magnetospheric electrons, and galactic cosmic rays. For \ce{CH3CN}, one photochemical model predicted a \ce{^{14}N/^{15}N} value as 120--130 in the lower stratosphere. This is much higher than that for \ce{HCN} and \ce{HC3N}, $\sim$67--94. By analyzing archival data obtained by the Atacama Large Millimeter/submillimeter Array (ALMA), we successfully detected submillimeter rotational transitions of \ce{CH3C^{15}N} ($J$ = 19--18) locate at the 338 GHz band in Titan's atmospheric spectra. By comparing those observations with the simultaneously observed \ce{CH3CN} ($J$ = 19--18) lines at the 349 GHz band, which probe from 160 to $\sim$400 km altitude, we then derived \ce{^{14}N/^{15}N} in \ce{CH3CN} as 125$^{+145}_{-44}$. Although the range of the derived value shows insufficient accuracy due to data quality limitations, the best-fit value suggests that \ce{^{14}N/^{15}N} for \ce{CH3CN} is higher than values that have been previously observed and theoretically predicted for \ce{HCN} and \ce{HC3N}. This may be explained by the different \ce{N2} dissociation sources according to the altitudes, as suggested by a recent photochemical model.

[51]  arXiv:2001.01495 [pdf, other]

Title: Stellar atmospheric parameters of FGK-type stars from high-resolution optical and near-infrared CARMENES spectra

Authors: E. Marfil, H. M. Tabernero, D. Montes, J. A. Caballero, M. G. Soto, J. I. González Hernández, A. Kaminski, E. Nagel, S. V. Jeffers, A. Reiners, I. Ribas, A. Quirrenbach, P. J. Amado

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

With the purpose of assessing classic spectroscopic methods on high-resolution and high signal-to-noise ratio spectra in the near-infrared wavelength region, we selected a sample of 65 F-, G-, and K-type stars observed with CARMENES, the new, ultra-stable, double-channel spectrograph at the 3.5 m Calar Alto telescope. We computed their stellar atmospheric parameters ($T_{\rm eff}$, $\log{g}$, $\xi$, and [Fe/H]) by means of the StePar code, a Python implementation of the equivalent width method that employs the 2017 version of the MOOG code and a grid of MARCS model atmospheres. We compiled four Fe I and Fe II line lists suited to metal-rich dwarfs, metal-poor dwarfs, metal-rich giants, and metal-poor giants that cover the wavelength range from 5300 to 17100 angstroms, thus substantially increasing the number of identified Fe I and Fe II lines up to 653 and 23, respectively. We examined the impact of the near-infrared Fe I and Fe II lines upon our parameter determinations after an exhaustive literature search, placing special emphasis on the 14 $Gaia$ benchmark stars contained in our sample. Even though our parameter determinations remain in good agreement with the literature values, the increase in the number of Fe I and Fe II lines when the near-infrared region is taken into account reveals a deeper $T_{\rm eff}$ scale that might stem from a higher sensitivity of the near-infrared lines to $T_{\rm eff}$.

[52]  arXiv:2001.01527 [pdf, other]

Title: The distance of the long period Cepheid RS Puppis from its remarkable light echoes

Authors: Pierre Kervella

Comments: 4 pages, 2 figures, proceedings of the conference "Stars and their variability observed from space" (Vienna, 19-23 August 2019)

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

The Milky Way Cepheid RS Puppis is a particularly important calibrator for the Leavitt law (the Period-Luminosity relation). It is a rare, long period pulsator (P=41.5 days), and a good analog of the Cepheids observed in distant galaxies. It is the only known Cepheid to be embedded in a large (~0.5 pc) dusty nebula, that scatters the light from the pulsating star. Due to the light travel time delay introduced by the scattering on the dust, the brightness and color variations of the Cepheid imprint spectacular light echoes on the nebula. I here present a brief overview of the studies of this phenomenon, in particular through polarimetric imaging obtained with the HST/ACS camera. These observations enabled us to determine the geometry of the nebula and the distance of RS Pup. This distance determination is important in the context of the calibration of the Baade-Wesselink technique and of the Leavitt law.

[53]  arXiv:2001.01529 [pdf, ps, other]

Title: The Cluster AgeS Experiment (CASE). Variable stars in the field of the globular cluster M10

Authors: M. Rozyczka (1), W. Narloch (1,2 and 3), A. Schwarzenberg - Czerny (1), I. B. Thompson (4), R. Poleski (5), W. Pych (1) ((1) Nicolaus Copernicus Astronomical Center, Warsaw, Poland, (2) Universidad de Concepción, Departamento de Astronomia, Concepción, Chile, (3) Millennium Institute of Astrophysics, Santiago, Chile, (4) The Observatories of the Carnegie Institution for Science, Pasadena, CA, Department of Astronomy, Ohio State University, Columbus, OH)

Journal-ref: Acta Astronomica, 2018, 68, 237-258

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

The field of the globular cluster M10 (NGC 6254) was monitored between 1998 and 2015 in a search for variable stars. V -light curves were derived for 40 variables or likely variables, most of which are new detections. Proper motions obtained within the CASE project indicate that 18 newly detected variables and 14 previously known ones are members or likely members of the cluster, including one RRc-type, three type II Cepheids, and 14 SX Phe-type pulsators, one contact binary, and six semi-regular red giants. As a byproduct of the search we discovered a candidate binary comprised of main sequence stars with the record-short orbital period of 0.042 d. We also confirmed the photometric variability of the red straggler M10-VLA1 hinted at by Shishkovsky et al. (2018), who discovered this object spectroscopically. In Appendix 1 we show that CASE proper motion measurements are in a good agreement with those retrieved from the Gaia archive, while Appendix 2 presents evidence for low frequency {\gamma} Doradus-type oscillations in SX Phe stars belonging to M10.

[54]  arXiv:2001.01530 [pdf, other]

Title: Galactic Magnetic Field Bias on Inferences from UHECR Data

Authors: Björn Eichmann, Tobias Winchen

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

A consequence of Liouville's theorem indicates that the recently observed large scale anisotropy in the arrival direction of Ultra-High-Energy Cosmic Rays (UHECRs) cannot be produced by the Galactic magnetic field, thus this anisotropy already needs to be present outside our Galaxy. But in this case, the observed energy spectrum and composition of UHECRs differs from the one outside of the Milky Way, due to the suppression or the amplification of the UHECR flux from certain directions by the Galactic magnetic field. In this work, we investigate this effect for the case of a dipole and a quadrupole anisotropy, respectively, for the widely-used JF12 magnetic field model. We investigate boundaries on the maximal amplitude of the observed anisotropy and the maximal charge number of UHECRs. Furthermore, the flux modification is discussed in the light of the Auger data on the recent dipole and also the chemical composition. We find that this modification effect is small for the investigated magnetic field model and observed mean dipole directions, but the large directional uncertainties of the measurements do in principle allow for a flux modification of up to 10%.

[55]  arXiv:2001.01563 [pdf, other]

Title: Understanding galaxy formation and evolution through an all-sky submillimetre spectroscopic survey

Authors: Mattia Negrello, Matteo Bonato, Zhen-Yi Cai, Helmut Dannerbauer, Gianfranco De Zotti, Jacques Delabrouille, Douglas Scott

Comments: 17 pages, 7 figures, submitted to PASA

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

We illustrate the extraordinary discovery potential for extragalactic astrophysics of a far-IR/submm all-sky spectroscopic survey with a 3m-class space telescope. Spectroscopy provides both a 3D view of the Universe and allows us to take full advantage of the sensitivity of present-day instrumentation, overcoming the spatial confusion that affects broadband far-IR/submm surveys. Emission lines powered by star formation will be detected in galaxies out to $z \simeq 8$. It will provide measurements of spectroscopic redshifts, SFRs, dust masses, and metal content for millions of galaxies at the peak epoch of cosmic star formation and of hundreds of them at the epoch of reionization. Many of these galaxies will be strongly lensed; the brightness amplification and stretching of their sizes will make it possible to investigate (by means of follow-up with high-resolution instruments) their internal structure and dynamics on the scales of giant molecular clouds. This will provide direct information on the physics driving the evolution. Furthermore, the arc-min resolution of the telescope at submm wavelengths is ideal for detecting the cores of galaxy proto-clusters, out to the epoch of reionization. Tens of millions of these galaxy-clusters-in-formation will be detected at $z \simeq 2$-3, with a tail out to $z \simeq 7$, and thousands of detections at 6 < z < 7. Their study will allow us to track the growth of the most massive halos well beyond what is possible with classical cluster surveys (mostly limited to $z < 1.5$-2), tracing the history of star formation in dense environments and teaching us how star formation and galaxy-cluster formation are related across all epochs. Such a survey will overcome the current lack of spectroscopic redshifts of dusty star-forming galaxies and galaxy proto-clusters, representing a quantum leap in far-IR/submm extragalactic astrophysics.

[56]  arXiv:2001.01590 [pdf, other]

Title: On The Photodesorption of CO$_2$ Ice Analogues: The Formation of Atomic C in The Ice and the Effect of The VUV Emission Spectrume

Authors: N.-E. Sie, G.M. Muñoz Caro, Z.-H. Huang, R. Martín-Doménech, A. Fuente, Y.-J. Chen

Comments: 11 pages, 11 figures

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

CO$_2$ ice has a phase transition at 35 K when its structure changes from amorphous to crystalline. Using Reflection absorption Infrared Spectroscopy (RAIRS), \"Oberg et al. observed that the photodesorption yield of CO$_2$ ice deposited at 60 K and irradiated at 18 K is 40% lower than that of CO$_2$ ice deposited and irradiated at 18 K. In this work, CO$_2$ ices were deposited at 16-60 K and UV-irradiated at 16 K to rule out the temperature effect and figure out the relationship between photodesorption yield and ice structure. IR spectroscopy is a common method used for measurement of the photodesorption yield in ices. We found that undetectable C atoms produced in irradiated CO$_2$ ice can account for 33% of the amount of depleted CO$_2$ molecules in the ice. A quantitative calibration of QMS was therefore performed to convert the measured ion current into photodesorption yield. During various irradiation periods, the dominant photodesorbing species were CO, O$_2$, and CO$_2$, and their photodesorption yields in CO$_2$ ices deposited at different temperature configurations were almost the same, indicating that ice morphology has no effect on the photodesorption yield of CO$_2$ ice. In addition, we found that the lower desorption yield reported by Mart\'in-Dom\'enech et al. is due to a linear relationship between the photodesorption yield and the combination of energy distribution of Microwave-Discharge Hydrogen-flow Lamp (MDHL) and UV absorption cross section of ices.

[57]  arXiv:2001.01625 [pdf, other]

Title: Long-term multi-frequency maser observations of the intermediate-mass young stellar object G107.298+5.639

Authors: Mateusz Olech, Marian Szymczak, Paweł Wolak, Eric Gérard, Anna Bartkiewicz

Comments: 20 pages, 15 figures

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

Periodic flares of maser emission are thought to be induced either by variations of the seed photon flux in young binary systems or the pump rate regulated by stellar and accretion luminosities. We seek to study the variability of four maser transitions of three different species in G107.298+5.639 to constrain the dominant mechanism of periodic flares. Light curves of the 6.7 GHz methanol and 22.2 GHz water vapour maser were obtained with the Torun 32m radio telescope over 39 and 34 cycles, respectively. The target was also monitored at the 1.6 GHz hydroxyl transitions with the Nan\c{c}ay radio telescope over 13 cycles. All these maser lines were imaged using VLBI arrays. The study confirms alternating flares of the methanol and water masers with a period of 34.4d and reveals the synchronised behaviour of the methanol and hydroxyl masers in this source. The observed spatial distribution of the methanol maser cloudlets and the measured time delays of the flares of individual features imply a ring-like structure of radius 240au and thickness 30au. Internal proper motions indicate that the velocity of methanol cloudlets is dominated by a disc-wind component of about 5km/s. The methanol emission detected during only one VLBI observation is located in a region about 550au from a central star, which also exhibits OH maser flares. The erratic appearance of methanol features can be related to a powering object of relatively low luminosity which, during some variability cycles, can excite molecules only in the nearest part of the disc. A careful analysis of the maser and infrared light curves reveal a strong correlation between the 6.7 GHz line and the infrared flux densities supporting a radiative pumping of the maser. The synchronised behaviour of the hydroxyl and methanol transitions indicates a common pumping mechanism for the periodic flares of G107.298+5.639.

[58]  arXiv:2001.01632 [pdf, other]

Title: Chemistry under EUV Irradiation of H$_2$-CO-N$_2$ Gas Mixtures: Implications for Photochemistry in the Outer CSE of Evolved Stars

Authors: Jérémy Bourgalais, David V. Bekaert, Aurore Bacmann, Bernard Marty, Nathalie Carrasco

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

{CircumStellar Envelopes (CSEs) of stars are complex chemical objects for which theoretical models encounter difficulties in elaborating a comprehensive overview of the occurring chemical processes. Along with photodissociation, ion-neutral reactions and dissociative recombination might play an important role in controlling molecular growth in outer CSEs. The aim of this work is to provide experimental insights into pathways of photochemistry-driven molecular growth within outer CSEs to draw a more complete picture of the chemical processes occurring within these molecule-rich environments. A simplified CSE environment was therefore reproduced in the laboratory through gas-phase experiments exposing relevant gas mixtures to an Extreme UltraViolet (EUV) photon source. This photochemical reactor should ultimately allow us to investigate chemical processes and their resulting products occurring under conditions akin to outer CSEs. We used a recently developed EUV lamp coupled to the APSIS photochemical cell to irradiate CSE relevant gas mixtures of H$_2$, CO and N$_2$, at one wavelength, 73.6 nm. The detection and identification of chemical species in the photochemical reactor was achieved through in-situ mass spectrometry analysis of neutral and cationic molecules. We find that exposing CO-N$_2$-H$_2$ gas mixtures to EUV photons at 73.6 nm induces photochemical reactions that yield the formation of complex, neutral and ionic species. Our work shows that N$_2$H$^+$ can be formed through photochemistry along with highly oxygenated ion molecules like HCO$^+$ in CSE environments. We also observe neutral N-rich organic species including triazole and aromatic molecules. These results confirm the suitability of our experimental setting to investigate photochemical reactions and provide fundamental insights into the mechanisms of molecular growth in the outer CSEs.

[59]  arXiv:2001.01643 [pdf, other]

Title: Monitoring of the radio galaxy M87 during a low emission state from 2012 to 2015 with MAGIC

Authors: MAGIC Collaboration: V. A. Acciari (1), S. Ansoldi (2,23), L. A. Antonelli (3), A. Arbet Engels (4), C. Arcaro (29,30), D. Baack (5), A. Babić (6), B. Banerjee (7), P. Bangale (14), U. Barres de Almeida (8), J. A. Barrio (9), J. Becerra González (1), W. Bednarek (10), L. Bellizzi (11), E. Bernardini (12,16), A. Berti (13), J. Besenrieder (14), W. Bhattacharyya (12), C. Bigongiari (3), A. Biland (4), O. Blanch (15), G. Bonnoli (11), Ž. Bošnjak (6), G. Busetto (16), R. Carosi (17), G. Ceribella (14), Y. Chai (14), A. Chilingaryan (18), S. Cikota (6), S. M. Colak (15), U. Colin (14), E. Colombo (1), J. L. Contreras (9), J. Cortina (19), S. Covino (3), V. D'Elia (3), P. Da Vela (17), F. Dazzi (3), A. De Angelis (16), B. De Lotto (2), M. Delfino (15,26), J. Delgado (15,26), et al. (147 additional authors not shown)

Comments: 12 pages, 4 figures, accepted on MNRAS

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

M87 is one of the closest (z=0.00436) extragalactic sources emitting at very-high-energies (VHE, E > 100 GeV). The aim of this work is to locate the region of the VHE gamma-ray emission and to describe the observed broadband spectral energy distribution (SED) during the low VHE gamma-ray state. The data from M87 collected between 2012 and 2015 as part of a MAGIC monitoring programme are analysed and combined with multi-wavelength data from Fermi-LAT, Chandra, HST, EVN, VLBA and the Liverpool Telescope. The averaged VHE gamma-ray spectrum can be fitted from 100GeV to 10TeV with a simple power law with a photon index of (-2.41 $\pm$ 0.07), while the integral flux above 300GeV is $(1.44 \pm 0.13) \times 10^{-12} cm^{-2} s^{-1}$. During the campaign between 2012 and 2015, M87 is generally found in a low emission state at all observed wavelengths. The VHE gamma-ray flux from the present 2012-2015 M87 campaign is consistent with a constant flux with some hint of variability ($\sim3\sigma$) on a daily timescale in 2013. The low-state gamma-ray emission likely originates from the same region as the flare-state emission. Given the broadband SED, both a leptonic synchrotron self Compton and a hybrid photo-hadronic model reproduce the available data well, even if the latter is preferred. We note, however, that the energy stored in the magnetic field in the leptonic scenario is very low suggesting a matter dominated emission region.

[60]  arXiv:2001.01670 [pdf, other]

Title: The Strikingly Metal-Rich Halo of the Sombrero Galaxy

Authors: Roger E. Cohen (1), Paul Goudfrooij (1), Oleg Y. Gnedin (2), William E. Harris (3), Rupali Chandar (4), Thomas H. Puzia (5), Ruben Sanchez-Janssen (6) ((1) STScI, (2) U. Michigan, (3) McMaster University, (4) U. Toledo, (5) PUC, (6) STFC UK Astronomy Tech. Centre, Royal Observatory, Edinburgh)

Comments: ApJ accepted

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

The nature of the Sombrero galaxy (M 104 = NGC 4594) has remained elusive despite many observational studies at a variety of wavelengths. Here we present Hubble Space Telescope imaging of two fields at $\sim$16 and 33 kpc along the minor axis to examine stellar metallicity gradients in the extended spheroid. We use this imaging, extending more than 2 mag below the tip of the red giant branch (TRGB), in combination with artificial star tests to forward model observed color-magnitude diagrams (CMDs), measuring metallicity distribution functions (MDFs) at different radii along the minor axis. An important and unexpected result is that the halo of the Sombrero is strikingly metal-rich: even the outer field, located at $\sim$17 effective radii of the bulge, has a median metallicity [Z/H]$\sim$-0.15 and the fraction of stars with [Z/H]<-1.0 is negligible. This is unprecedented among massive galaxy halos studied to date, even among giant ellipticals. We find significant radial metallicity gradients, characterized by an increase in the fraction of metal-poor stars with radius and a gradient in median metallicity of $\sim$-0.01 dex/kpc. The density profile is well fit by power laws with slopes that exhibit a dependence on metallicity, with flatter slopes for more metal-poor stars. We discuss our results in the context of recent stellar MDF studies of other nearby galaxies and potential formation scenarios for the Sombrero galaxy.

[61]  arXiv:2001.01710 [pdf, other]

Title: Does Gravity Fall Down? Evidence for Gravitational Wave Deflection Along the Line of Sight to GW 170817

Authors: David Rubin, Istvan Szapudi, Benjamin J. Shappee, Gagandeep S. Anand

Comments: Under review with ApJL

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

We present a novel test of general relativity (GR): measuring the geometric component of the time delay due to gravitational lensing. GR predicts that photons and gravitational waves follow the same geodesic paths and thus experience the same geometric time delay. We show that for typical systems, the time delays are tens of seconds, and thus can dominate over astrophysical delays in the timing of photon emission. For the case of GW 170817, we use a multi-plane lensing code to evaluate the time delay due to four massive halos along the line of sight. From literature mass and distance measurements of these halos, we establish at high confidence (significantly greater than 5 sigma) that the gravitational waves of GW 170817 underwent gravitational deflection to arrive within 1.7 seconds of the photons.

[62]  arXiv:2001.01716 [pdf, other]

Title: Manganese Indicates a Transition from Sub- to Near-Chandrasekhar Type Ia Supernovae in Dwarf Galaxies

Authors: Mithi A. C. de los Reyes (1), Evan N. Kirby (1), Ivo R. Seitenzahl (2), Ken J. Shen (3) ((1) Caltech, (2) UNSW-ADFA, (3) UC Berkeley)

Comments: 24 pages, 8 figures. Submitted to ApJ

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

Manganese (Mn) abundances are sensitive probes of the progenitors of Type Ia supernovae (SNe). In this work, we present a catalog of manganese abundances in dwarf spheroidal satellites of the Milky Way, measured using medium-resolution spectroscopy. Using a simple chemical evolution model, we infer the manganese yield of Type Ia SNe in the Sculptor dwarf spheroidal galaxy (dSph) and compare to theoretical yields. The sub-solar yield from Type Ia SNe ($\mathrm{[Mn/Fe]}_{\mathrm{Ia}}=-0.30_{-0.03}^{+0.03}$ at $\mathrm{[Fe/H]}=-1.5$ dex, with negligible dependence on metallicity) implies that sub-Chandrasekhar-mass (sub-$M_{\mathrm{Ch}}$) white dwarf progenitors are the dominant channel of Type Ia SNe at early times in this galaxy, although some fraction ($\gtrsim20\%$) of $M_{\mathrm{Ch}}$ Type Ia or Type Iax SNe are still needed to produce the observed yield. However, this result does not hold in all environments. In particular, we find that dSph galaxies with extended star formation histories (Leo I, Fornax dSphs) appear to have higher [Mn/Fe] at a given metallicity than galaxies with early bursts of star formation (Sculptor dSph), suggesting that $M_{\mathrm{Ch}}$ progenitors may become the dominant channel of Type Ia SNe at later times in a galaxy's chemical evolution.

Cross-lists for Tue, 7 Jan 20

[63]  arXiv:1907.05488 (cross-list from physics.flu-dyn) [pdf, ps, other]

Title: Analysis of azimuthal magnetorotational instability of rotating MHD flows and Tayler instability via an extended Hain-Lust equation

Authors: Rong Zou, Joris Labarbe, Yasuhide Fukumoto, Oleg N. Kirillov

Comments: 24 pages, 16 figures, refs added, typos corrected

Journal-ref: Phys. Rev. E (2020) 101: 013201

Subjects: Fluid Dynamics (physics.flu-dyn); Solar and Stellar Astrophysics (astro-ph.SR); Plasma Physics (physics.plasm-ph)

We consider a differentially rotating flow of an incompressible electrically conducting and viscous fluid subject to an external axial magnetic field and to an azimuthal magnetic field that is allowed to be generated by a combination of an axial electric current external to the fluid and electrical currents in the fluid itself. In this setting we derive an extended version of the celebrated Hain-Lust differential equation for the radial Lagrangian displacement that incorporates the effects of the axial and azimuthal magnetic fields, differential rotation, viscosity, and electrical resistivity. We apply the Wentzel-Kramers-Brillouin method to the extended Hain-Lust equation and derive a new comprehensive dispersion relation for the local stability analysis of the flow to three-dimensional disturbances. We confirm that in the limit of low magnetic Prandtl numbers, in which the ratio of the viscosity to the magnetic diffusivity is vanishing, the rotating flows with radial distributions of the angular velocity beyond the Liu limit, become unstable subject to a wide variety of the azimuthal magnetic fields, and so is the Keplerian flow. In the analysis of the dispersion relation we find an evidence of a new long-wavelength instability which is caught also by the numerical solution of the boundary value problem for a magnetized Taylor-Couette flow.

[64]  arXiv:2001.00935 (cross-list from gr-qc) [pdf, other]

Title: Gravitational Theory of Cosmology, Galaxies and Galaxy Clusters

Authors: J. W. Moffat

Comments: 9 pages, 2 figures. arXiv admin note: substantial text overlap with arXiv:1409.0853, arXiv:1510.07037

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

A modified gravitational theory explains early universe and late time cosmology, galaxy and galaxy cluster dynamics. The modified gravity (MOG) theory extends general relativity (GR) by three extra degrees of freedom: a scalar field $G$, enhancing the strength of the Newtonian gravitational constant $G_N$, a gravitational, spin 1 vector graviton field $\phi_\mu$, and the effective mass $\mu$ of the ultralight spin 1 graviton. For $t < t_{\rm rec}$, where $t_{\rm rec}$ denotes the time of recombination and re-ionization, the density of the vector graviton $\rho_\phi > \rho_b$, where $\rho_b$ is the density of baryons, while for $t > t_{\rm rec}$ we have $\rho_b > \rho_\phi$. The matter density is parameterized by $\Omega_M=\Omega_b+\Omega_\phi+\Omega_r$ where $\Omega_r=\Omega_\gamma+\Omega_\nu$. For the cosmological parameter values obtained by the Planck Collaboration, the CMB acoustical oscillation power spectrum, polarization and lensing data can be fitted as in the $\Lambda$CDM model. When the baryon density $\rho_b$ dominates the late time universe, MOG explains galaxy rotation curves, the dynamics of galaxy clusters, galaxy lensing and the galaxy clusters matter power spectrum without dominant dark matter.

[65]  arXiv:2001.00948 (cross-list from hep-ph) [pdf, other]

Title: Speeding Up Dark Matter With Solar Neutrinos

Authors: Yue Zhang

Comments: 6 pages, 3 figures

Subjects: High Energy Physics - Phenomenology (hep-ph); Solar and Stellar Astrophysics (astro-ph.SR); High Energy Physics - Experiment (hep-ex)

We present a novel mechanism of using solar neutrinos to speed up dark matter, inspired by the fact that neutrinos are the most energetic particles from the Sun with a well-understood spectrum. In a neutrino portal dark sector model, we show that dark matter with sub-GeV mass could be accelerated by the $pp$ neutrinos to velocities well above $10^{-3}c$ and capable of depositing large enough energy at direct detection experiments. A crucial ingredient of this mechanism is the dissociation of stable dark matter bound states that exist in Nature. The resulting dark matter velocity distribution bears a strong resemblance in shape to the solar neutrino spectrum. As an application, we derive a leading limit on light dark matter interaction by reinterpreting a recent PICO experiment result.

[66]  arXiv:2001.00984 (cross-list from physics.ed-ph) [pdf]

Title: Assessing the influence of one astronomy camp over 50 years

Authors: Hannah Dalgleish, Josh Veitch-Michaelis

Comments: 10 pages, 4 figures

Journal-ref: Nat Astron 3, 1043-1047 (2019)

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

The International Astronomical Youth Camp has benefited thousands of lives during its 50-year history. We explore the pedagogy behind this success, review a survey taken by more than 300 previous participants, and discuss some of the challenges the camp faces in the future.

[67]  arXiv:2001.01030 (cross-list from hep-ph) [pdf, other]

Title: Decay of Cosmic Global String Loops

Authors: Ayush Saurabh, Tanmay Vachaspati, Levon Pogosian

Comments: 8 pages; 10 figures; An animation of a representative loop can be seen at this https URL

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

We numerically study the decay of cosmic global string loops due to radiation of Goldstone bosons and massive scalar ($\chi$) particles. The length of loops we study range from 200-1000 times the width of the string core. We find that the lifetime of a loop is $\approx 1.4 L$. The energy spectrum of Goldstone boson radiation has a $k^{-1}$ fall off, where $k$ is the wavenumber, and a sharp peak at $k \approx m_\chi/2$, where $m_\chi$ is the mass of $\chi$. The latter is a new feature and implies a peak at high energies (MeV-GeV) in the cosmological distribution of QCD axions.

[68]  arXiv:2001.01209 (cross-list from physics.ins-det) [pdf, other]

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

Authors: Steven Juhyung Lee, Ben Kilminster, Anna Machiolo

Comments: Proceedings to be submitted to JINST for IPRD19 conference

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

Dark Matter In CCDs (DAMIC) is a silicon detector apparatus used primarily for searching for low-mass dark matter using the silicon bulk of the Charge-Coupled Devices (CCDs) as targets. The silicon target within each CCD is \SI{675}{\micro\meter} thick and its top surface is divided into over 16 million \SI{15}{\micro\meter} $\times$ \SI{15}{\micro\meter} pixels. The DAMIC collaboration has installed a number of these CCDs at SNOLAB. As of 2019, DAMIC at SNOLAB has reached operational conditions with leakage current less than \SI{8.2e-22}{\ampere\per\centi\meter\squared} and a readout noise of \SI{1.6}{}e$^-$, achieved with 5 CCDs. A new DAMIC apparatus will be installed at Laboratoire Souterrain de Modane (LSM). The DAMIC at Modane (DAMIC-M) collaboration will be using an improved version of CCDs designed by Lawrence Berkeley National Laboratory (LBNL) with skipper amplifiers that use non-destructive readout with multiple-sampling enabling the CCDs to achieve a readout noise of 0.068 e-. The low readout noise, in conjunction with low leakage current of these skipper CCDs, will allow DAMIC-M to observe physics processes with collisions energies as low as 1 eV. The DAMIC-M experiment will consist of an array of 50 large-area skipper CCDs with more than 36 million pixels in each CCD. The submitted proceeding will introduce the DAMIC apparatus at SNOLAB and its results and the capabilities and the status of the new DAMIC-M experiment.

[69]  arXiv:2001.01221 (cross-list from math.DS) [pdf, other]

Title: Global time-regularization of the gravitational $N$-body problem

Authors: M. Antoñana, P. Chartier, J. Makazaga, A. Murua

Subjects: Dynamical Systems (math.DS); Earth and Planetary Astrophysics (astro-ph.EP)

This work considers the gravitational $N$-body problem and introduces time-reparametrization functions that allow to define globally solutions of the $N$-body equations. First, a lower bound of the radius of convergence of the solution to the original equations is derived, which suggests an appropriate time-reparametrization. In the new fictitious time $\tau$, it is then proved that any solution exists for all $\tau \in \mathbb{R}$, and that it is uniquely extended as a holomorphic function to a strip of fixed width. As a by-product, a global power series representation of the solutions of the $N$-body problem is obtained. Noteworthy, our global time-regularization remain valid in the limit when one of the masses vanishes. Finally, numerical experiments show the efficiency of the new time-regularization functions for some $N$-problems with close encounters.

[70]  arXiv:2001.01237 (cross-list from hep-ph) [pdf, other]

Title: Baryon asymmetry and detectable Gravitational Waves from Electroweak phase transition

Authors: Ruiyu Zhou, Ligong Bian

Comments: 8 pages, 6 figures, comments welcome

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

We study the possibility of achieving baryon asymmetry explanation and detectable gravitational wave from the Electroweak phase transition with two Higgs doublet models. With the type-I and type-II 2HDM, we found that it is hard to account for the observed baryon asymmetry of the Universe with the non-local Electroweak baryogenesis, and current theoretical and experimental bounds make most parameter spaces fail to produce detectable gravitational waves. We find that it is possible to address baryon asymmetry of the Universe and predict detectable gravitational wave during the phase transition with local Electroweak baryogengesis after considering the CP-violation magnitude allowed by the current electron electric dipole moment measurements.

[71]  arXiv:2001.01462 (cross-list from gr-qc) [pdf, other]

Title: Search for Advanced LIGO Single Interferometer Compact Binary Coalescence Signals in Coincidence with Gamma-Ray Events in Fermi-GBM

Authors: C. Stachie, T. Dal Canton, E. Burns, N. Christensen, R. Hamburg, M. Briggs, J. Broida, A. Goldstein, F. Hayes, T. Littenberg, P. Shawhan, J. Veitch, P. Veres, C. A. Wilson-Hodge

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

Presented is the description of a new and general method used to search for $\gamma$-ray counterparts to gravitational-wave (GW) triggers. This method is specifically applied to single GW detector triggers. Advanced LIGO data from observing runs O1 and O2 were analyzed, thus each GW trigger comes from either the LIGO-Livingston or the LIGO-Hanford interferometer. For each GW trigger, Fermi Gamma-ray Burst Monitor data is searched and the most significant subthreshold signal counterpart is selected. Then, a methodology is defined in order to establish which of GW-$\gamma$-ray pairs are likely to have a common origin. For that purpose an association ranking statistic is calculated from which a false alarm rate is derived. The events with the highest ranking statistics are selected for further analysis consisting of LIGO detector characterization and parameter estimation. The $\gamma$-ray signal characteristics are also evaluated. We find no significant candidates from the search.

Replacements for Tue, 7 Jan 20

[72]  arXiv:1706.06837 (replaced) [pdf, other]

Title: Properties of the irregular satellite system around Uranus inferred from K2, Herschel and Spitzer observations

Authors: A. Farkas-Takács, Cs. Kiss, A. Pál, L. Molnár, Gy.M. Szabó, O. Hanyecz, K. Sárneczky, R. Szabó, G. Marton, M. Mommert, R. Szakáts, T. Müller, L.L. Kiss

Comments: Accepted for publication in the Astronomical Journal

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

[73]  arXiv:1712.02782 (replaced) [pdf, other]

Title: Nonlinear Effective Theory of Dark Energy

Authors: Giulia Cusin, Matthew Lewandowski, Filippo Vernizzi

Comments: v3: typo fixed

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

[74]  arXiv:1712.02783 (replaced) [pdf, other]

Title: Dark Energy and Modified Gravity in the Effective Field Theory of Large-Scale Structure

Authors: Giulia Cusin, Matthew Lewandowski, Filippo Vernizzi

Comments: v3: typo fixed

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

[75]  arXiv:1803.10454 (replaced) [pdf, other]

Title: Echoes from the Abyss: A highly spinning black hole remnant for the binary neutron star merger GW170817

Authors: Jahed Abedi (AEI, Hanover), Niayesh Afshordi (Waterloo/PI)

Comments: 2019 Buchalter Cosmology First Prize, Dedicated to the memories of Stephen Hawking and Joe Polchinski, Matches the version published in JCAP + added note regarding confirmation by electromagnetic observations

Journal-ref: JCAP 1911, no. 11, 010 (2019)

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

[76]  arXiv:1807.11239 (replaced) [pdf, ps, other]

Title: Secondary-electron radiation accompanying hadronic GeV-TeV gamma-rays from supernova remnants

Authors: Yan Huang, Zhuo Li, Wei Wang, Xiaohong Zhao

Comments: 9 pages, 5 figures and 1 table, MNRAS accepted

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

[77]  arXiv:1812.04977 (replaced) [pdf, other]

Title: Surviving companions of Type Ia supernovae: theory and observations

Authors: Pilar Ruiz-Lapuente

Comments: 80 pages, 17 Figures, 3 Tables. Accepted as invited review to New Astronomy Reviews. Final version

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

[78]  arXiv:1902.04550 (replaced) [pdf, other]

Title: A footprint of standard cosmology in the future observations of low--frequency gravitational waves

Authors: Jorge Alfaro, Mauricio Gamonal

Comments: 24 pages, 1 appendix, 12 figures, 3 tables. Submitted to ApJ on March 5, 2019

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

[79]  arXiv:1903.11074 (replaced) [pdf, other]

Title: Polarisation of high energy gamma-rays after scattering

Authors: Celine Boehm, Andres Olivares-Del Campo, Maura Ramirez-Quezada, Ye-ling Zhou

Comments: 34 pages, 8 figures, 6 appendices, typos corrected, explanations and references added, matches JCAP published version

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

[80]  arXiv:1905.00337 (replaced) [pdf, other]

Title: On the energetics of a possible relativistic jet associated with the binary neutron star merger candidate S190425z

Authors: M. Saleem, L. Resmi, K. G. Arun, S. Mohan

Comments: 5 pages, 3 figures, Accepted for publication in ApJ

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

[81]  arXiv:1905.12820 (replaced) [pdf, other]

Title: Does black hole continuum spectrum signal f(R) gravity in higher dimensions?

Authors: Indrani Banerjee, Bhaswati Mandal, Soumitra SenGupta

Comments: 32 pages, 5 figures, 2 tables

Journal-ref: Physical Review D, 101, 024013 (2020)

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

[82]  arXiv:1906.06831 (replaced) [pdf, ps, other]

Title: Baryon Physics and Tight Coupling Approximation in Boltzmann Codes

Authors: Masroor C. Pookkillath, Antonio De Felice, Shinji Mukohyama

Comments: 29 pages, 6 figures, uses revtex, matches with published version. Code available at: this http URL

Journal-ref: Universe 2020, 6(1), 6

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

[83]  arXiv:1906.08235 (replaced) [pdf, other]

Title: The Prospects of Observing Tidal Disruption Events with the LSST

Authors: Katja Bricman, Andreja Gomboc

Comments: 11 pages, 7 figures, submitted to ApJ, revised version

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

[84]  arXiv:1907.01822 (replaced) [pdf, other]

Title: How well do we understand the belt/zone circulation of Giant Planet atmospheres?

Authors: Leigh N. Fletcher, Yohai Kaspi, Tristan Guillot, Adam P. Showman

Comments: 25 pages, 6 figures, Space Science Reviews, accepted

Journal-ref: Space Science Reviews (2020)

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

[85]  arXiv:1907.05051 (replaced) [pdf, other]

Title: Emission peaks in the light curve of core collapse supernovae by late jets

Authors: Noa Kaplan, Noam Soker (Technion, Israel)

Comments: Accepted for publication in MNRAS

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

[86]  arXiv:1907.08515 (replaced) [pdf, other]

Title: Cosmological information content in redshift-space power spectrum of SDSS-like galaxies in the quasi-nonlinear regime up to $k=0.3\,h\,$Mpc$^{-1}$

Authors: Yosuke Kobayashi, Takahiro Nishimichi, Masahiro Takada, Ryuichi Takahashi

Comments: Accepted for publication in Phys. Rev. D; 32 pages, 18 figures

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

[87]  arXiv:1908.02841 (replaced) [pdf, other]

Title: AGNs at the cosmic dawn: predictions for future surveys from a $Λ$CDM cosmological model

Authors: Andrew J. Griffin (1), Cedric G. Lacey (1), Violeta Gonzalez-Perez (2,3), Claudia del P. Lagos (4,5,6), Carlton M. Baugh (1), Nikos Fanidakis (7,8) ((1) ICC Durham, (2) ICG Portsmouth, (3) Lancaster, (4) ICRAR, UWA, (5) ASTRO 3D, (6) DAWN, Copenhagen, (7) MPIA Heidelberg, (8) BASF)

Comments: MNRAS submitted. This is the second paper from a paper that has been split in two

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

[88]  arXiv:1908.07150 (replaced) [pdf, other]

Title: Optimizing galaxy samples for clustering measurements in photometric surveys

Authors: Dimitrios Tanoglidis, Chihway Chang, Joshua Frieman

Comments: 19 pages, 12 figures, to be submitted to MNRAS

Journal-ref: MNRAS, 491, 3535 (2020)

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

[89]  arXiv:1908.09689 (replaced) [pdf, other]

Title: First Operation of TES Microcalorimeters in Space with the Micro-X Sounding Rocket

Authors: J.S. Adams, R. Baker, S.R. Bandler, N. Bastidon, M.E. Danowski, W.B. Doriese, M.E. Eckart, E. Figueroa-Feliciano, D.C. Goldfinger, S.N.T. Heine, G.C. Hilton, A.J.F. Hubbard, R.L. Kelley, C.A. Kilbourne, R.E. Manzagol-Harwood, D. McCammon, T. Okajima, F.S. Porter, C.D. Reintsema, P. Serlemitsos, S.J. Smith, J.N. Ullom, P. Wikus

Comments: 9 pages, 6 figures, Accepted to the JLTP for LTD-18

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

[90]  arXiv:1909.04695 (replaced) [pdf, other]

Title: Simulating Metal Mixing of Both Common and Rare Enrichment Sources in a Low Mass Dwarf Galaxy

Authors: Andrew Emerick, Greg L. Bryan, Mordecai-Mark Mac Low

Comments: Submitted to ApJ. First revision. 17 pages, 12 figures

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

[91]  arXiv:1909.04795 (replaced) [pdf, other]

Title: Blandford-Znajek process as Alfvénic superradiance

Authors: Sousuke Noda, Yasusada Nambu, Takuma Tsukamoto, Masaaki Takahashi

Comments: 7 pages, 5 figures, Matched to published version

Journal-ref: Phys. Rev. D 101, 023003 (2020)

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

[92]  arXiv:1909.05864 (replaced) [pdf, other]

Title: NIHAO-UHD: The properties of MW-like stellar disks in high resolution cosmological simulations

Authors: Tobias Buck (1), Aura Obreja (2), Andrea V. Macciò (3,4), Ivan Minchev (1), Aaron A. Dutton (3), Jeremiah P. Ostriker (5,6) ((1) AIP, (2) USM, (3) NYUAD, (4) MPIA, (5) Columbia University, (6) Princeton University)

Comments: simulations publicly available at this http URL , 19 pages (14 main text, 5 appendix), 14 figures (plus 4 appendix), accepted by MNRAS

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

[93]  arXiv:1909.06085 (replaced) [pdf, other]

Title: Neutron Star Mergers and How to Study Them

Authors: Eric Burns

Comments: Submitted to Living Reviews in Relativity

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

[94]  arXiv:1909.07274 (replaced) [pdf, other]

Title: Efficient wavefront sensing for space-based adaptive optics

Authors: He Sun, N. Jeremy Kasdin, Robert Vanderbei

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

[95]  arXiv:1909.07404 (replaced) [pdf, other]

Title: Embedding globular clusters in dark matter minihalos solves the cusp-core and timing problems in the Fornax dwarf galaxy

Authors: Pierre Boldrini, Roya Mohayaee, Joseph Silk

Comments: 11 pages, 15 figures, Accepted by MNRAS

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

[96]  arXiv:1910.01431 (replaced) [pdf, ps, other]

Title: Possibility of rapid neutron star cooling with the realistic equation of state

Authors: Akira Dohi, Ken'ichiro Nakazato, Masa-aki Hashimoto, Yasuhide Matsuo, Tsuneo Noda

Comments: 16 pages, 12 figures, Fig.10 corrected, accepted for publication in PTEP

Journal-ref: Prog.Theor.Exp.Phys.2019,113E01

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

[97]  arXiv:1910.02836 (replaced) [pdf, other]

Title: Analysis of Multi-Hour Continuous Observations of Seven Millisecond Pulsars

Authors: Brent J. Shapiro-Albert, Maura A. McLaughlin, Michael T. Lam, James M. Cordes, Joe K. Swiggum

Comments: 18 pages, 5 figures, 5 tables, accepted by ApJ

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

[98]  arXiv:1910.04053 (replaced) [pdf, other]

Title: Properties of the dense core population in Orion B as seen by the Herschel Gould Belt survey

Authors: V. Konyves, Ph. Andre, D. Arzoumanian, N. Schneider, A. Men'shchikov, S. Bontemps, B. Ladjelate, P. Didelon, S. Pezzuto, M. Benedettini, A. Bracco, J. Di Francesco, S. Goodwin, K. L. J. Rygl, Y. Shimajiri, L. Spinoglio, D. Ward-Thompson, G. J. White

Comments: In press in Astronomy and Astrophysics. arXiv admin note: text overlap with arXiv:1507.05926

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

[99]  arXiv:1910.06338 (replaced) [pdf, other]

Title: Capture of interstellar objects: a source of long-period comets

Authors: Tom Hands, Walter Dehnen

Comments: 5 pages, 3 figures, accepted for publication in MNRAS

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

[100]  arXiv:1910.10602 (replaced) [pdf, other]

Title: Primordial black hole formation in inflationary $α$-attractor models

Authors: Rafid Mahbub

Comments: 29 pages, 10 figures, corrected typos, updated final section and references

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

[101]  arXiv:1910.11877 (replaced) [pdf, ps, other]

Title: Searching for z > 6.5 Analogs Near the Peak of Cosmic Star Formation

Authors: Xinnan Du, Alice E. Shapley, Mengtao Tang, Daniel P. Stark, Crystal L. Martin, Bahram Mobasher, Michael W. Topping, Jacopo Chevallard

Comments: 22 pages, 9 figures, accepted for publication in ApJ

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

[102]  arXiv:1910.12422 (replaced) [pdf, other]

Title: Detecting Double Neutron Stars with LISA

Authors: Mike Y. M. Lau, Ilya Mandel, Alejandro Vigna-Gómez, Coenraad J. Neijssel, Simon Stevenson, Alberto Sesana

Comments: Accepted by the Monthly Notices of the Royal Astronomical Society, added comparison with two more binary evolution prescriptions

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

[103]  arXiv:1910.12943 (replaced) [pdf, other]

Title: Absolute Calibration Strategies for the Hydrogen Epoch of Reionization Array and Their Impact on the 21 cm Power Spectrum

Authors: Nicholas S. Kern, Joshua S. Dillon, Aaron R. Parsons, Christopher L. Carilli, Gianni Bernardi, Zara Abdurashidova, James E. Aguirre, Paul Alexander, Zaki S. Ali, Yanga Balfour, Adam P. Beardsley, Tashalee S. Billings, Judd D. Bowman, Richard F. Bradley, Philip Bull, Jacob Burba, Steven Carey, Carina Cheng, David R. DeBoer, Matt Dexter, Eloy de Lera Acedo, John Ely, Aaron Ewall-Wice, Nicolas Fagnoni, Randall Fritz, Steve R. Furlanetto, Kingsley Gale-Sides, Brian Glendenning, Deepthi Gorthi, Bradley Greig, Jasper Grobbelaar, Ziyaad Halday, Bryna J. Hazelton, Jacqueline N. Hewitt, Jack Hickish, Daniel C. Jacobs, Austin Julius, Joshua Kerrigan, Piyanat Kittiwisit, Saul A. Kohn, Matthew Kolopanis, Adam Lanman, Paul La Plante, Telalo Lekalake, Adrian Liu, David MacMahon, Lourence Malan, Cresshim Malgas, et al. (24 additional authors not shown)

Comments: Accepted to ApJ

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

[104]  arXiv:1910.13460 (replaced) [pdf, other]

Title: Strong Supercooling as a Consequence of Renormalization Group Consistency

Authors: Vedran Brdar, Alexander J. Helmboldt, Manfred Lindner

Comments: 12 pages, 2 figures, matches version published in JHEP

Journal-ref: JHEP12(2019)158

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

[105]  arXiv:1910.14334 (replaced) [pdf, other]

Title: Realistic collisional water transport during terrestrial planet formation: Self-consistent modeling by an N-body--SPH hybrid code

Authors: C. Burger (1 and 2), Á. Bazsó (1), C. M. Schäfer (2) ((1) University of Vienna, Department of Astrophysics, Austria, (2) University of Tübingen, Institute of Astronomy and Astrophysics, Germany)

Comments: A&A in press, 32 pages, 23 figures

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

[106]  arXiv:1911.09282 (replaced) [pdf, other]

Title: Fission of super-heavy elements: $^{132}$Sn-plus-the-rest, or $^{208}$Pb-plus-the-rest ?

Authors: C. Ishizuka, X. Zhang, M.D. Usang, F.A. Ivanyuk, S. Chiba

Comments: 4 pages, 4 figures

Subjects: Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Experiment (nucl-ex)

[107]  arXiv:1912.00785 (replaced) [pdf, other]

Title: Gauge Independence of Induced Gravitational Waves

Authors: Keisuke Inomata, Takahiro Terada

Comments: 16 pages, 1 figure; published version (minor revision)

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

[108]  arXiv:1912.02027 (replaced) [pdf, ps, other]

Title: Non-thermal emission in lobes of radio galaxies: III. 3C 98, Pictor A, DA 240, Cygnus A, 3C 326, and 3C 236

Authors: Massimo Persic (INAF Trieste, Bologna U.), Yoel Rephaeli (Tel-Aviv U., UCSD)

Comments: 8 pages, 4 figures; a few typos corrected; several missing references added

Journal-ref: MNRAS, 491, 5740-5746 (2020)

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

[109]  arXiv:1912.08838 (replaced) [pdf, other]

Title: Parker Solar Probe Observations of a Dust Trail in the Orbit of (3200) Phaethon

Authors: Karl Battams, Matthew M. Knight, Michael S.P. Kelley, Brendan M. Gallagher, Russell A. Howard, Guillermo Stenborg

Comments: 14 Pages, 7 Figures; Accepted to ApJS (Parker Solar Probe Special Edition)

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

[110]  arXiv:1912.10152 (replaced) [src]

Title: Detection of missing baryons in galaxy groups with kinetic Sunyaev-Zel'dovich effect

Authors: Seunghwan Lim, H.J. Mo, Huiyuan Wang, Xiaohu Yang

Comments: We replace the submission of the old version of the manuscript (arXiv:1712.08619; same paper, basically) with the manuscript of this new version, and remove this new submission to avoid confusion, which we newly submitted only to make it noticed that there was a very significant revision to the old version although they are still not a separate paper, but same paper

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

[111]  arXiv:1912.12032 (replaced) [pdf, other]

Title: Primordial Black Holes in Higgs-$R^2$ Inflation as a whole dark matter

Authors: Dhong Yeon Cheong, Sung Mook Lee, Seong Chan Park

Comments: 6 pages with references, 5 figures; v2: minor revisions, references added

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

[112]  arXiv:1912.13130 (replaced) [pdf]

Title: Production of nitric oxide by a fragmenting bolide: An exploratory numerical study

Authors: Mihai L. Niculescu, Elizabeth A. Silber, Reynold E. Silber

Comments: 30 pages, 9 figures

Journal-ref: Mathematical Methods in Applied Sciences (2020)

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

[113]  arXiv:1912.13198 (replaced) [pdf, other]

Title: The Morphological, Elastic, and Electric Properties of Dust Aggregates in Comets: A Close Look at COSIMA/Rosetta's Data on Dust in Comet 67P/Churyumov-Gerasimenko

Authors: Hiroshi Kimura, Martin Hilchenbach, Sihane Merouane, John Paquette, Oliver Stenzel

Comments: 17 pages, 12 figures, 1 tables, to appear in Planetary and Space Science

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

[114]  arXiv:2001.00040 (replaced) [pdf, other]

Title: Relaxing the TCC Bound on Inflationary Cosmology?

Authors: Vahid Kamali, Robert Brandenberger

Comments: 5 pages, no figures; 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)

[115]  arXiv:2001.00043 (replaced) [pdf, other]

Title: Strengthening the TCC Bound on Inflationary Cosmology

Authors: Robert Brandenberger, Edward Wilson-Ewing

Comments: 5 pages, 1 figure; references added and 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)

[116]  arXiv:2001.00049 (replaced) [pdf, other]

Title: High-resolution Spectra and Biosignatures of Earth-like Planets Transiting White Dwarfs

Authors: Thea Kozakis, Zifan Lin, Lisa Kaltenegger

Comments: 10 pages, 1 table, 4 figures; submitted to ApJL

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

[117]  arXiv:2001.00275 (replaced) [pdf, ps, other]

Title: Reduction of the canonical Hamiltonian of the metric GR to its natural form

Authors: Alexei M. Frolov

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

[118]  arXiv:2001.00755 (replaced) [pdf, other]

Title: Unveiling the temporal properties of MAXI J1820+070 through AstroSat observations

Authors: Sneha Prakash Mudambi, Bari Maqbool, Ranjeev Misra, Sabhya Hebbar, J. S. Yadav, Shivappa B. Gudennavar, Bubbly S. G

Comments: The manuscript has been accepted for publication in Astrophysical Journal Letters (ApJL). The article contains 8 pages, 4 figures and 1 Table

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

[119]  arXiv:2001.00873 (replaced) [pdf, other]

Title: Onset of Cosmic Reionization: Evidence of An Ionized Bubble Merely 680 Myrs after the Big Bang

Authors: V. Tilvi (ASU), S. Malhotra (NASA), J. E. Rhoads (NASA), A. Coughlin (Chandler Com College), Z. Zheng (Shanghai Obs.), S. L. Finkelstein (UT Austin), S. Veilleux (Univ. Maryland), B. Mobasher (UC Riverside), J. Wang (USTC), R. Probst (NOAO), R. Swaters (Univ Maryland), P. Hibon (ESO), B. Joshi (ASU) J. Zabl (Univ Lyon), T. Jiang (ASU), J. Pharo (ASU), H. Yang (ASU)

Comments: Submitted after addressing referee's comments

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

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