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New submissions for Thu, 21 May 20

[1]  arXiv:2005.09642 [pdf, ps, other]

Title: COMPASS: VLBI Beacons In Support of Lunar Science and Exploration

Authors: T. M. Eubanks

Comments: Paper accepted for publication in the proceedings of the XXXIII General Assembly and Scientific Symposium (GASS) of the International Union of Radio Science (Union Radio Scientifique Internationale-URSI)

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

The large constellations of spacecraft planned for use in cislunar space (on the Lunar surface, in Lunar orbit, and in the vicinity of the Lunar Gateway) require new solutions for positioning, navigation and timing (PNT). Here, I describe COMPASS (Combined Observational Methods for Positional Awareness in the Solar System), a spacecraft navigation system to provide cost-effective techniques for the positioning of large numbers of spacecraft in cislunar space. COMPASS will use beacons that emit coherent ultra-wideband signals designed to be interoperable with existing and future Very Long Baseline Interferometry (VLBI) networks. Using differential VLBI, COMPASS will provide rapid determination of the interferometric phase delay with picosecond level accuracy during routine VLBI observing sessions. Multi-baseline phase-referenced COMPASS-VLBI observations with simultaneous calibrator observations should thus enable sub-meter accuracy transverse positioning and meter level lunar orbit determination using with small femtospacecraft beacons and a few seconds of observation per position determination.

[2]  arXiv:2005.09653 [pdf, other]

Title: VLA-ALMA Spectroscopic Survey in the Hubble Ultra Deep Field (VLASPECS): Total Cold Gas Masses and CO Line Ratios for z=2-3 "Main Sequence" Galaxies

Authors: Dominik A. Riechers (Cornell, MPIA), Leindert A. Boogaard (Leiden), Roberto Decarli (INAF Bologna), Jorge Gonzalez-Lopez (Carnegie), Ian Smail (Durham), Fabian Walter (MPIA, NRAO), Manuel Aravena (Diego Portales), Christopher L. Carilli (NRAO, Cambridge), Paulo C. Cortes (JAO, NRAO), Pierre Cox (IAP), Tanio Diaz-Santos (Diego Portales, CASSACA), Jacqueline A. Hodge (Leiden), Hanae Inami (Hiroshima), Rob J. Ivison (ESO), Melanie Kaasinen (MPIA, ITA Heidelberg), Jeff Wagg (SKA), Axel Weiss (MPIfR), Paul van der Werf (Leiden)

Comments: 9 pages, 4 figures, 1 table, to appear in ApJ Letters (accepted May 19, 2020)

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

Using the NSF's Karl G. Jansky Very Large Array (VLA), we report six detections of CO(J=1-0) emission and one upper limit in z=2-3 galaxies originally detected in higher-J CO emission in the Atacama Large submillimeter/Millimeter Array (ALMA) Spectroscopic Survey in the Hubble Ultra Deep Field (ASPECS). From the CO(J=1-0) line strengths, we measure total cold molecular gas masses of M_gas = 2.4-11.6 x 10^10 (alpha_CO/3.6) Msun. We also measure a median CO(J=3-2) to CO(J=1-0) line brightness temperature ratio of r_31 = 0.84 +/- 0.26, and a CO(J=7-6) to CO(J=1-0) ratio range of r_71 <0.05 to 0.17. These results suggest that CO(J=3-2) selected galaxies may have a higher CO line excitation on average than CO(J=1-0) selected galaxies, based on the limited, currently available samples from the ASPECS and VLA CO Luminosity Density at High Redshift (COLDz) surveys. This implies that previous estimates of the cosmic density of cold gas in galaxies based on CO(J=3-2) measurements should be revised down by a factor of ~=2 on average based on assumptions regarding CO excitation alone. This correction further improves the agreement between the best currently existing constraints on the cold gas density evolution across cosmic history from line scan surveys, and the implied characteristic gas depletion times.

[3]  arXiv:2005.09654 [pdf, other]

Title: Resolving small-scale cold circumgalactic gas in TNG50

Authors: Dylan Nelson, Prateek Sharma, Annalisa Pillepich, Volker Springel, Ruediger Pakmor, Rainer Weinberger, Mark Vogelsberger, Federico Marinacci, Lars Hernquist

Comments: MNRAS submitted, comments welcome

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

We use the high-resolution TNG50 cosmological magnetohydrodynamical simulation to explore the properties and origin of cold circumgalactic medium (CGM) gas around massive galaxies (M* > 10^11 Msun) at intermediate redshift (z~0.5). We discover a significant abundance of small-scale, cold gas structure in the CGM of 'red and dead' elliptical systems, as traced by neutral HI and MgII. Halos can host tens of thousands of discrete absorbing cloudlets, with sizes of order a kpc or smaller. With a Lagrangian tracer analysis, we show that cold clouds form due to strong drho/rho >> 1 gas density perturbations which stimulate thermal instability. These local overdensities trigger rapid cooling from the hot virialized background medium at ~10^7 K to radiatively inefficient ~10^4 K clouds, which act as cosmologically long-lived, 'stimulated cooling' seeds in a regime where the global halo does not satisfy the classic tcool/tff < 10 criterion. Furthermore, these small clouds are dominated by magnetic rather than thermal pressure, with plasma beta << 1, suggesting that magnetic fields may play an important role. The number and total mass of cold clouds both increase with resolution, and the ~8x10^4 Msun cell mass of TNG50 enables the ~few hundred pc, small-scale CGM structure we observe to form. Finally, we contrast against observations from the COS-LRG, LRG-RDR, COS-Halos, and SDSS LRG surveys. We broadly find that our recent, high-resolution cosmological simulations produce sufficiently high covering fractions of extended, cold gas as observed to surround massive galaxies.

[4]  arXiv:2005.09656 [pdf, other]

Title: Optical spectra of FO Aquarii during low and high accretion rates

Authors: M. R. Kennedy, P. M. Garnavich, C. Littlefield, T. R. Marsh, P. Callanan, R. P. Breton, T. Augusteijn, R. M. Wagner, R. P. Ashley, M. Neric

Comments: 19 pages, 14 figures, accepted for publication in Monthly Notices of the Royal Astronomical Society

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

Between May 2016 and September 2018, the intermediate polar (IP) FO Aquarii exhibited two distinct low states and one failed low state. We present optical spectroscopy of FO Aquarii throughout this period, making this the first detailed study of an accretion disc during a low state in any IP. Analysis of these data confirm that the low states are the result of a drop in the mass transfer rate between the secondary star and the magnetic white dwarf primary, and are characterised by a decrease in the system's brightness coupled with a change of the system's accretion structures from an accretion disc-fed geometry to a combination of disc-fed and ballistic stream-fed accretion, and that effects from accretion onto both magnetic poles become detectable. The failed low state only displays a decrease in brightness, with the accretion geometry remaining primarily disc-fed. We also find that the WD appears to be exclusively accretion disc-fed during the high state. There is evidence for an outflow close to the impact region between the ballistic stream and the disc which is detectable in all of the states. Finally, there is marginal evidence for narrow high velocity features in the H$\alpha$ emission line during the low states which may arise due to an outflow from the WD. These features may be evidence of a collimated jet, a long predicted yet elusive feature of cataclysmic variables.

[5]  arXiv:2005.09657 [pdf, other]

Title: Persistent starspot signals on M dwarfs: multi-wavelength Doppler observations with the Habitable-zone Planet Finder and Keck/HIRES

Authors: Paul Robertson, Gudmundur Stefansson, Suvrath Mahadevan, Michael Endl, William D. Cochran, Corey Beard, Chad F. Bender, Scott A. Diddams, Nicholas Duong, Eric B. Ford, Connor Fredrick, Samuel Halverson, Fred Hearty, Rae Holcomb, Lydia Juan, Shubham Kanodia, Jack Lubin, Andrew J. Metcalf, Andrew Monson, Joe P. Ninan, Jonathan Palafoutas, Lawrence W. Ramsey, Arpita Roy, Christian Schwab, Ryan C. Terrien, Jason T. Wright

Comments: Accepted for publication in the Astrophysical Journal

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

Young, rapidly-rotating M dwarfs exhibit prominent starspots, which create quasiperiodic signals in their photometric and Doppler spectroscopic measurements. The periodic Doppler signals can mimic radial velocity (RV) changes expected from orbiting exoplanets. Exoplanets can be distinguished from activity-induced false positives by the chromaticity and long-term incoherence of starspot signals, but these qualities are poorly constrained for fully-convective M stars. Coherent photometric starspot signals on M dwarfs may persist for hundreds of rotations, and the wavelength dependence of starspot RV signals may not be consistent between stars due to differences in their magnetic fields and active regions. We obtained precise multi-wavelength RVs of four rapidly-rotating M dwarfs (AD Leo, G 227-22, GJ 1245B, GJ 3959) using the near-infrared (NIR) Habitable-zone Planet Finder, and the optical Keck/HIRES spectrometer. Our RVs are complemented by photometry from Kepler, TESS, and the Las Cumbres Observatory (LCO) network of telescopes. We found that all four stars exhibit large spot-induced Doppler signals at their rotation periods, and investigated the longevity and optical-to-NIR chromaticity for these signals. The phase curves remain coherent much longer than is typical for Sunlike stars. Their chromaticity varies, and one star (GJ 3959) exhibits optical and NIR RV modulation consistent in both phase and amplitude. In general, though, we find that the NIR amplitudes are lower than their optical counterparts. We conclude that starspot modulation for rapidly-rotating M stars frequently remains coherent for hundreds of stellar rotations, and gives rise to Doppler signals that, due to this coherence, may be mistaken for exoplanets.

[6]  arXiv:2005.09658 [pdf, other]

Title: Variability of OB stars from TESS southern Sectors 1-13 and high-resolution IACOB and OWN spectroscopy

Authors: S. Burssens, S. Simón-Díaz, D. M. Bowman, G. Holgado, M. Michielsen, A. de Burgos, N. Castro, R.H. Barbá, C. Aerts

Comments: Accepted for publication in A&A. 18(+47) pages, 15(+100) figures, 3(+2) tables

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

Lack of high-precision long-term continuous photometric data for large samples of stars has prevented the large-scale exploration of pulsational variability in the OB star regime. As a result, the candidates for in-depth asteroseismic modelling remained limited to a few tens of dwarfs. The TESS nominal space mission has surveyed the southern sky, yielding continuous data of at least 27 d for hundreds of OB stars. We aim to couple TESS data in the southern sky with spectroscopy to study the variability over mass and evolution. We focus mainly on the presence of coherent pulsation modes that may or may not be present in the theoretical instability domains and unravel all frequency behaviour in the amplitude spectra of the TESS data. We compose a sample of 98 OB-type stars observed by TESS in Sectors 1-13 and with available high-resolution spectroscopy gathered by the IACOB and OWN surveys. We present the short-cadence 2-min light curves of dozens of OB-type stars, that have one or more spectra in the IACOB or OWN database. Based on these light curves and their Lomb-Scargle periodograms we perform variability classification and frequency analysis, and place the stars in the spectroscopic Hertzsprung-Russell diagram to interpret the variability in an evolutionary context. We deduce diverse origins of the variability found in all of the 98 OB stars in the TESS data. Among these we find several new variable stars, including three hybrid pulsators, three eclipsing binaries, high frequency modes in a Be star, and potential heat-driven pulsations in two Oe stars. We identify stars for which future asteroseismic modelling is possible, provided mode identification is achieved. By comparing the position of the variables to theoretical instability strips we discuss the current shortcomings in non-adiabatic pulsation theory, and the distribution of pulsators in the upper Hertzsprung-Russell diagram.

[7]  arXiv:2005.09660 [pdf, other]

Title: High-redshift Damped Ly-alpha Absorbing Galaxy Model Reproducing the N(HI)-Z Distribution

Authors: J.-K. Krogager, P. Møller, L. B. Christensen, P. Noterdaeme, J. P. U. Fynbo, W. Freudling

Comments: Accepted to MNRAS, 8 pages

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

We investigate how damped Lyman-$\alpha$ absorbers (DLAs) at z ~ 2-3, detected in large optical spectroscopic surveys of quasars, trace the population of star-forming galaxies. Building on previous results, we construct a model based on observed and physically motivated scaling relations in order to reproduce the bivariate distributions of metallicity, Z, and HI column density, N(HI). Furthermore, the observed impact parameters for galaxies associated to DLAs are in agreement with the model predictions. The model strongly favours a metallicity gradient, which scales with the luminosity of the host galaxy, with a value of $\gamma$* = -0.019 $\pm$ 0.008 dex kpc$^{-1}$ for L* galaxies that gets steeper for fainter galaxies. We find that DLAs trace galaxies over a wide range of galaxy luminosities, however, the bulk of the DLA cross-section arises in galaxies with L ~ 0.1 L* at z ~ 2.5 broadly consistent with numerical simulations.

[8]  arXiv:2005.09661 [pdf, other]

Title: A Cold, Massive, Rotating Disk Galaxy 1.5 Billion Years after the Big Bang

Authors: Marcel Neeleman (MPIA), J. Xavier Prochaska (UCSC), Nissim Kanekar (NCRA), Marc Rafelski (STScI)

Comments: Published in Nature on May 20, 2020

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

Massive disk galaxies like the Milky Way are expected to form at late times in traditional models of galaxy formation, but recent numerical simulations suggest that such galaxies could form as early as a billion years after the Big Bang through the accretion of cold material and mergers. Observationally, it has been difficult to identify disk galaxies in emission at high redshift, in order to discern between competing models of galaxy formation. Here we report imaging, with a resolution of about 1.3 kiloparsecs, of the 158-micrometre emission line from singly ionized carbon, the far-infrared dust continuum and the near-ultraviolet continuum emission from a galaxy at a redshift of 4.2603, identified by detecting its absorption of quasar light. These observations show that the emission arises from gas inside a cold, dusty, rotating disk with a rotational velocity of 272 kilometres per second. The detection of emission from carbon monoxide in the galaxy yields a molecular mass that is consistent with the estimate from the ionized carbon emission of about 72 billion solar masses. The existence of such a massive, rotationally supported, cold disk galaxy when the Universe was only 1.5 billion years old favours formation through either cold-mode accretion or mergers, although its large rotational velocity and large content of cold gas remain challenging to reproduce with most numerical simulations.

[9]  arXiv:2005.09663 [pdf, ps, other]

Title: What has quenched the massive spiral galaxies?

Authors: Yu Luo (1), Zongnan Li (2), Xi Kang (3 and 1), Zhiyuan Li (2) ((1) PMO, (2) NJU, (3) ZJU)

Comments: 5 papes, 3 figures, accepted for publication in MNRAS Letters

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

Quenched massive spiral galaxies have attracted great attention recently, as more data is available to constrain their environment and cold gas content. However, the quenching mechanism is still uncertain, as it depends on the mass range and baryon budget of the galaxy. In this letter, we report the identification of a rare population of very massive, quenched spiral galaxies with stellar mass $\gtrsim10^{11}{\rm~M_\odot}$ and halo mass $\gtrsim10^{13}{\rm~M_\odot}$ from the Sloan Digital Sky Survey at redshift $z\sim0.1$. Our CO observations using the IRAM-30m telescope show that these galaxies contain only a small amount of molecular gas. Similar galaxies are also seen in the state-of-the-art semi-analytical models and hydro-dynamical simulations. It is found from these theoretical models that these quenched spiral galaxies harbor massive black holes, suggesting that feedback from the central black holes has quenched these spiral galaxies. This quenching mechanism seems to challenge the popular scenario of the co-evolution between massive black holes and massive bulges.

[10]  arXiv:2005.09664 [pdf, ps, other]

Title: Element Stratification in the Middle-Aged Type Ia Supernova Remnant G344.7-0.1

Authors: Kotaro Fukushima, Hiroya Yamaguchi, Patrick O. Slane, Sangwook Park, Satoru Katsuda, Hidetoshi Sano, Laura A. Lopez, Paul P. Plucinsky, Shogo B. Kobayashi, Kyoko Matsushita

Comments: 19 pages, 10 figures

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

Despite their importance, details of Type Ia supernovae (SNe Ia) remain elusive. X-ray measurements of the element distributions in supernova remnants (SNRs) offer important clues to understanding the explosion and nucleosynthesis mechanisms for SNe Ia. However, it has been challenging to observe the entire ejecta mass in X-rays for young SNRs, because the central ejecta may not have been heated by the reverse shock yet. Here we present over 200-ks Chandra observations of the Type Ia SNR G344.7-0.1, whose age is old enough for the reverse shock to have reached the SNR center, providing an opportunity to investigate the distribution of the entire ejecta mass. We reveal a clear stratification of heavy elements with a centrally-peaked distribution of the Fe ejecta surrounded by intermediate-mass elements (IMEs: Si, S, Ar Ca) with an arc-like structure. The centroid energy of the Fe K emission is marginally lower in the central Fe-rich region than in the outer IME-rich regions, suggesting that the Fe ejecta were shock heated more recently. These results are consistent with a prediction of standard SN Ia models, where the heavier elements are synthesized in the interior of an exploding white dwarf. We find, however, that the peak location of the Fe K emission is slightly offset to the west with respect to the geometric center of the SNR. This apparent asymmetry is likely due to the inhomogeneous density distribution of the ambient medium, consistent with our radio observations of the ambient molecular and neutral gas.

[11]  arXiv:2005.09666 [pdf, other]

Title: Beware of commonly used approximations II: estimating systematic biases in the best-fit parameters

Authors: José Luis Bernal, Nicola Bellomo, Alvise Raccanelli, Licia Verde

Comments: 21 pages (+6 pages of references), 6 figures, 1 table

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

Cosmological parameter estimation from forthcoming experiments promise to reach much greater precision than current constraints. As statistical errors shrink, the required control over systematic errors increases. Therefore, models or approximations that were sufficiently accurate so far, may introduce significant systematic biases in the parameter best-fit values and jeopardize the robustness of cosmological analyses. We present a general expression to estimate a priori the systematic error introduced in parameter inference due to the use of insufficiently good approximations in the computation of the observable of interest or the assumption of an incorrect underlying model. Although this methodology can be applied to measurements of any scientific field, we illustrate its power by studying the effect of modeling the angular galaxy power spectrum incorrectly. We also introduce Multi_CLASS, a new, public modification of the Boltzmann code CLASS, which includes the possibility to compute angular cross-power spectra for two different tracers. We find that significant biases in most of the cosmological parameters are introduced if one assumes the Limber approximation or neglects lensing magnification in modern galaxy survey analyses, and the effect is in general larger for the multi-tracer case, especially for the parameter controlling primordial non-Gaussianity of the local type, $f_{\rm NL}$.

[12]  arXiv:2005.09667 [pdf, other]

Title: Effective Opacity of the Intergalactic Medium from Galaxy Spectra Analysis

Authors: Jose S. Monzon, J. Xavier Prochaska, Khee-Gan Lee, John Chisholm

Comments: accepted to ApJ on 05/18/2020

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

We measure the effective opacity ($\tau_{eff}$) of the Intergalactic Medium (IGM) from the composite spectra of 281 Lyman-Break Galaxies (LBGs) in the redshift range $2 \lesssim z \lesssim 3$. Our spectra are taken from the COSMOS Lyman-Alpha Mapping And Tomographic Observations (CLAMATO) survey derived from the Low Resolution Imaging Spectrometer (LRIS) on the W.M. Keck I telescope. We generate composite spectra in two redshift intervals and fit them with spectral energy distribution (SED) models composed of simple stellar populations. Extrapolating these SED models into the Ly$\alpha$ forest, we measure the effective Ly$\alpha$ opacity ($\tau_{eff}$) in the $2.02 \leq z \leq 2.44$ range. At $z = 2.22$, we estimate $\tau_{eff} = 0.159 \pm 0.001$ from a power-law fit to the data. These measurements are consistent with estimates from quasar analyses at $z<2.5$ indicating that the systematic errors associated with normalizing quasar continua are not substantial. We provide a Gaussian Processes model of our results and previous $\tau_{eff}$ measurements that describes the steep redshift evolution in $\tau_{eff}$ from $z = 1.5 - 4$.

[13]  arXiv:2005.09682 [pdf, other]

Title: Data-driven derivation of stellar properties from photometric time series data using convolutional neural networks

Authors: Kirsten Blancato, Melissa Ness, Daniel Huber, Yuxi Lu, Ruth Angus

Comments: 33 pages, 10 figures, 2 tables. Submitted to ApJ

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

Stellar variability is driven by a multitude of internal physical processes that depend on fundamental stellar properties. These properties are our bridge to reconciling stellar observations with stellar physics, and for understanding the distribution of stellar populations within the context of galaxy formation. Numerous ongoing and upcoming missions are charting brightness fluctuations of stars over time, which encode information about physical processes such as rotation period, evolutionary state (such as effective temperature and surface gravity), and mass (via asteroseismic parameters). Here, we explore how well we can predict these stellar properties, across different evolutionary states, using only photometric time series data. To do this, we implement a convolutional neural network, and with data-driven modeling we predict stellar properties from light curves of various baselines and cadences. Based on a single quarter of \textit{Kepler} data, we recover stellar properties, including surface gravity for red giant stars (with an uncertainty of $\lesssim$ 0.06 dex), and rotation period for main sequence stars (with an uncertainty of $\lesssim$ 5.2 days, and unbiased from $\approx$5 to 40 days). Shortening the \textit{Kepler} data to a 27-day TESS-like baseline, we recover stellar properties with a small decrease in precision, $\sim$0.07 dex for log $g$ and $\sim$5.5 days for $P_{\rm rot}$, unbiased from $\approx$5 to 35 days. Our flexible data-driven approach leverages the full information content of the data, requires minimal feature engineering, and can be generalized to other surveys and datasets. This has the potential to provide stellar property estimates for many millions of stars in current and future surveys.

[14]  arXiv:2005.09692 [pdf, other]

Title: Resonant-line radiative transfer within power-law density profiles

Authors: Bing-Xin Lao, Aaron Smith

Comments: 17 pages, 15 figures, submitted to MNRAS, comments are welcome

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

Star-forming regions in galaxies are surrounded by vast reservoirs of gas capable of both emitting and absorbing Lyman-alpha (Lya) radiation. Observations of Lya emitters and spatially extended Lya haloes indeed provide insights into the formation and evolution of galaxies. However, due to the complexity of resonant scattering, only a few analytic solutions are known in the literature. We discuss several idealized but physically motivated scenarios to extend the existing formalism to new analytic solutions, enabling quantitative predictions about the transport and diffusion of Lya photons. This includes a closed form solution for the radiation field and derived quantities including the emergent flux, peak locations, energy density, average internal spectrum, number of scatters, outward force multiplier, trapping time, and characteristic radius. To verify our predictions, we employ a robust gridless Monte Carlo radiative transfer (GMCRT) method, which is straightforward to incorporate into existing ray-tracing codes but requires modifications to opacity-based calculations, including dynamical core-skipping acceleration schemes. We primarily focus on power-law density and emissivity profiles, however both the analytic and numerical methods can be generalized to other cases. Such studies provide additional intuition and understanding regarding the connection between the physical environments and observational signatures of galaxies throughout the Universe.

[15]  arXiv:2005.09698 [pdf, ps, other]

Title: The Catalogue of Cometary Orbits and their Dynamical Evolution

Authors: Małgorzata Królikowska, Piotr A. Dybczyński

Comments: 6 pages, 3 figures, public database: this https URL submitted for publication in A&A

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

The new cometary catalogue containing data for almost 300 long-period comets that were discovered before 2018 is announced (the CODE catalogue). This is the first catalogue containing cometary orbits in five stages of their dynamical evolution, covering three successive passages through the perihelion, except the hyperbolic comets which are treated in a different manner. For about 100 of these long-period comets, their non-gravitational orbits are given, and for a comparison also their orbits obtained while neglecting the existence of non-gravitational acceleration are included. For many of the presented comets different orbital solutions, based on the alternative force models or various subsets of positional data are additionally given. The preferred orbit is always clearly indicated for each comet.

[16]  arXiv:2005.09699 [pdf, other]

Title: Disc and wind in black hole X-ray binary MAXIJ1820+070 observed through polarized light during its 2018 outburst

Authors: Ilia A. Kosenkov, Alexandra Veledina, Andrei V. Berdyugin, Vadim Kravtsov, Vilppu Piirola, Svetlana V. Berdyugina, Takeshi Sakanoi, Masato Kagitani, Juri Poutanen

Comments: 5 pages, 2 figures, 1 table. Accepted to MNRAS Letters

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

We describe the first complete polarimetric dataset of the entire outburst of a low-mass black hole X-ray binary system and discuss the constraints for geometry and radiative mechanisms it imposes. During the decaying hard state, when the optical flux is dominated by the non-thermal component, the observed polarization is consistent with the interstellar values in all filters. During the soft state, the intrinsic polarization of the source is small, $\sim 0.15$ per cent in $B$ and $V$ filters, and is likely produced in the irradiated disc. A much higher polarization, reaching $\sim 0.5$ per cent in $V$ and $R$ filters, at position angle of $\sim 25^\circ$ observed in the rising hard state coincides in time with the detection of winds in the system. This angle coincides with the position angle of the jet. The detected optical polarization is best explained by scattering of the non-thermal (hot flow or jet base) radiation in an equatorial wind.

[17]  arXiv:2005.09720 [pdf, ps, other]

Title: Gravitational Fluctuations as an Alternative to Inflation III. Numerical Results

Authors: Herbert W. Hamber, Lu Heng Sunny Yu, Hasitha E. Pituwala Kankanamge

Comments: 44 pages, 10 figures

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

Power spectra play an important role in the theory of inflation, and their ability to reproduce current observational data to high accuracy is often considered a triumph of inflation, largely because of a lack of credible alternatives. In previous work we introduced an alternative picture for the cosmological power spectra based on the nonperturbative features of the quantum version of Einstein's gravity, instead of currently popular inflation models based on scalar fields. The key ingredients in this new picture are the appearance of a nontrivial gravitational vacuum condensate (directly related to the observed cosmological constant), and a calculable renormalization group running of Newton's G on cosmological scales. Results obtained previously were largely based on a semi-analytical treatment, and often suffered from the limitations of various approximations and simplifying assumptions. In this work, we extend and refine our previous calculations by laying out an updated and extended analysis, which now utilizes a set of suitably modified state-of-the-art numerical programs (ISiTGR, MGCAMB and MGCLASS) developed for observational cosmology. As a result, we are able to remove some of the approximations employed in our previous studies, leading to a number of novel and detailed physical predictions. These should help in potentially distinguish the vacuum condensate picture of quantum gravity from that of other models such as scalar field inflation. Here, besides the matter power spectrum P(k), we work out in detail predictions for what are referred to as the TT, TE, EE, BB angular spectra, as well as their closely related lensing spectra. However, the current limited precision of observational data today (especially on large angular scales) does not allow us yet to clearly prove or disprove either set of ideas.

[18]  arXiv:2005.09730 [pdf, other]

Title: Hints of a Population of Solar System Analog Planets from ALMA

Authors: Deryl Long, Ke Zhang, Richard Teague, Edwin Bergin

Comments: 8 pages, 3 figures, accepted to be published in The Astrophysical Journal Letters (May 18, 2020)

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

The recent ALMA DSHARP survey provided illuminating results on the diversity of substructures in planet forming disks. These substructures trace pebble-sized grains accumulated at local pressure maxima, possibly due to planet-disk interactions or other planet formation processes. DSHARP sources are heavily biased to large and massive disks that only represent the high (dust flux) tail end of the disk population. Thus it is unclear whether similar substructures and corresponding physical processes also occur in the majority of disks which are fainter and more compact. Here we explore the presence and characteristics of features in a compact disk around GQ Lup A, the effective radius of which is 1.5 to 10 times smaller than those of DSHARP disks. We present our analysis of ALMA 1.3mm continuum observations of the GQ Lup system. By fitting visibility profiles of the continuum emission, we find substructures including a gap at ~ 10 au. The compact disk around GQ Lup exhibits similar substructures to those in the DSHARP sample, suggesting that mechanisms of trapping pebble-sized grains are at work in small disks as well. Characteristics of the feature at ~ 10 au, if due to a hidden planet, are evidence of planet formation at Saturnian distances. Our results hint at a rich world of substructures to be identified within the common population of compact disks, and subsequently a population of solar system analogs within these disks. Such study is critical to understanding the formation mechanisms and planet populations in the majority of protoplanetary disks.

[19]  arXiv:2005.09753 [pdf, other]

Title: High-Contrast Integral Field Spectrograph (HCIFS): multi-spectral wavefront control and reduced-dimensional system identification

Authors: He Sun, Alexei Goun, Susan Redmond, Michael Galvin, Tyler Groff, Maxime Rizzo, N. Jeremy Kasdin

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

Any High-contrast imaging instrument in a future large ground-based or space-based telescopes will include an integral field spectrograph (IFS) for measuring broadband starlight residuals and characterizing the exoplanet's atmospheric spectrum. In this paper, we report the development of a high-contrast integral field spectrograph (HCIFS) at Princeton University and demonstrate its application in multi-spectral wavefront control. Moreover, we propose and experimentally validate a new reduced-dimensional system identification algorithm for an IFS imaging system, which improves the system's wavefront control speed, contrast and computational efficiency.

[20]  arXiv:2005.09757 [pdf, other]

Title: Studying Type II supernovae as cosmological standard candles using the Dark Energy Survey

Authors: T. de Jaeger, L. Galbany, S. González-Gaitán, R. Kessler, A. V. Filippenko, F. Förster, M. Hamuy, P. J. Brown, T. M. Davis, C. P. Gutiérrez, C. Inserra, G F. Lewis, A. Möller, D. Scolnic, M. Smith, D. Brout, D. Carollo, R. J. Foley, K. Glazebrook, S. R. Hinton, E. Macaulay, B. Nichol, M. Sako, N. E. Sommer, B. E. Tucker, T. M. C. Abbott, M. Aguena, S. Allam, J. Annis, S. Avila, E. Bertin, S. Bhargava, D. Brooks, D. L. Burke, A. Carnero Rosell, M. Carrasco Kind, J. Carretero, M. Costanzi, M. Crocce, L. N. da Costa, J. De Vicente, S. Desai, H. T. Diehl, P. Doel, A. Drlica-Wagner, T. F. Eifler, J. Estrada, S. Everett, B. Flaugher, P. Fosalba, J. Frieman, J. García-Bellido, E. Gaztanaga, D. Gruen, R. A. Gruendl, J. Gschwend, G. Gutierrez, W. G. Hartley, D. L. Hollowood, et al. (29 additional authors not shown)

Comments: 39 pages, 22 figures, 10 tables, Accepted for publication in MNRAS

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

Despite vast improvements in the measurement of the cosmological parameters, the nature of dark energy and an accurate value of the Hubble constant (H$_0$) in the Hubble-Lema\^itre law remain unknown. To break the current impasse, it is necessary to develop as many independent techniques as possible, such as the use of Type II supernovae (SNe II). The goal of this paper is to demonstrate the utility of SNe II for deriving accurate extragalactic distances, which will be an asset for the next generation of telescopes where more-distant SNe II will be discovered. More specifically, we present a sample from the Dark Energy Survey Supernova Program (DES-SN) consisting of 15 SNe II with photometric and spectroscopic information spanning a redshift range up to 0.35. Combining our DES SNe with publicly available samples, and using the standard candle method (SCM), we construct the largest available Hubble diagram with SNe II in the Hubble flow (70 SNe II) and find an observed dispersion of 0.27 mag. We demonstrate that adding a colour term to the SN II standardisation does not reduce the scatter in the Hubble diagram. Although SNe II are viable as distance indicators, this work points out important issues for improving their utility as independent extragalactic beacons: find new correlations, define a more standard subclass of SNe II, construct new SN II templates, and dedicate more observing time to high-redshift SNe II. Finally, for the first time, we perform simulations to estimate the redshift-dependent distance-modulus bias due to selection effects.

[21]  arXiv:2005.09759 [pdf, other]

Title: Observational appearance of rapidly rotating neutron stars: X-ray bursts, cooling tail method, and radius determination

Authors: Valery F. Suleimanov, Juri Poutanen, Klaus Werner

Comments: 17 pages, 16 figures, accepted for publication in Astronomy and Astrophysics

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

Neutron stars (NSs) in low-mass X-ray binaries rotate at frequencies high enough to significantly deviate from sphericity ($\nu_* \sim$ 200--600 Hz). We investigate the effects of rapid rotation on the observational appearance of a NS. We propose analytical formulae relating gravitational mass and equatorial radius of the rapidly rotating NS to the mass $M$ and radius $R$ of a non-rotating NS of the same baryonic mass using accurate fully relativistic computations. We compute spectra from an oblate rotating NS observed at different inclination angles using the modified oblate Schwarzschild (MOS) approximation, where light bending is computed in Schwarzschild metric, but frame dragging and quadrupole moment of a NS are approximately accounted for in the photon redshift calculations. We generalize the cooling tail method to the case of a rapidly rotating NS to obtain the most probable values of $M$ and $R$ of the corresponding non-rotating NS with the same baryonic mass. We approximate the local spectra from the NS surface by a diluted blackbody using previously computed NS atmosphere models. We show that the NS radius could be overestimated by 3--3.5 km for face-on stars of $R\approx 11$ km rotating at $\nu_* =$ 700 Hz if the version of the cooling tail method for a non-rotating NS is used. We apply the method to an X-ray burst observed from the NS rotating at $\nu_* \approx$ 532 Hz in SAX J1810.8$-$2609. The resulting radius of the non-rotating NS (assuming $M=1.5 M_\odot$) becomes $11.8\pm0.5$ km if it is viewed at inclination i=60 deg and $R=11.2\pm0.5$ km for a face-on view, which are smaller by 0.6 and 1.2 km than the radius obtained using standard cooling tail method ignoring rotation. The corresponding equatorial radii of these rapidly rotating NSs are 12.3$\pm 0.6$ km (for i=60 deg) and 11.6$\pm 0.6$\,km (for i=0 deg).

[22]  arXiv:2005.09793 [pdf, other]

Title: Quark-Novae in the outskirts of galaxies: An explanation of the Fast Radio Burst phenomenon

Authors: Rachid Ouyed, Denis Leahy, Nico Koning (Department of Physics and Astronomy, University of Calgary, Canada)

Comments: 57 pages (includes 16 tables and 11 figures)

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Plasma Physics (physics.plasm-ph)

We show that old isolated neutron stars in groups and clusters of galaxies experiencing a Quark-Nova phase (QN: an explosive transition to a quark star) may be the sources of FRBs. Each fragment ("chunk") of the ultra-relativistic QN ejecta provides a collisionless plasma for which the ambient medium (galactic/halo, the intra-group/intra-cluster medium) acts as a relativistic plasma beam. Plasma instabilities (the Buneman and the Buneman-induced thermal Weibel instabilities, successively) are induced by the beam in the chunk. These generate particle bunching and observed coherent emission at GHz frequency with a corresponding fluence in the Jy ms range. The duration (from micro-seconds to hundreds of milli-seconds), repeats (on timescales of minutes to months), frequency drift and the high occurrence rate of FRBs (a few per thousand years per galaxy) in our model are in good agreement with observed properties of FRBs. All FRBs intrinsically repeat in our model and non-repetition (i.e. the non detection of the fainter QN chunks) is detector-dependent and an artifact of the bandwidth and of the fluence sensitivity threshold. Key properties of FRB 121102 (its years of activity) and of FRB 180916.J0158+65 (its 16 day period) are recovered in our model. We give specific predictions, notably: (i) because of the viewing angle (Doppler) effect, sub-GHz detectors (CHIME) will be associated with dimmer and longer duration FRBs than GHz detectors (e.g. Parkes and ASKAP); (ii) CHIME should detect on average 5 times more FRBs from a given QN than ASKAP and Parkes; (iii) super FRBs (i.e. tens of thousands of Jy ms fluence) should be associated with intra-cluster medium QNe; (iii) monster FRBs (i.e. millions of Jy ms fluence) associated with inter-galactic medium QNe might plausibly occur with frequencies at the lower limit of the LOFAR's low-band antenna.

[23]  arXiv:2005.09795 [pdf, other]

Title: Chirp Mass and Spin of Binary Black Holes from First Star Remnants

Authors: Tomoya Kinugawa, Takashi Nakamura, Hiroyuki Nakano

Comments: comments welcome. Submitted to MNRAS

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

We performed Population III (Pop III) binary evolution by using population synthesis simulations for seven different models. We found that Pop III binaries tend to be binary black holes (BBHs) with chirp mass $M_{\rm chirp} \sim 30~M_{\odot}$ and they can merge at present day due to long merger time. The merger rate densities of Pop III BBHs at $z=0$ ranges 3.34--21.2 $\rm /yr/Gpc^3$ which is consistent with the aLIGO/aVIRGO result of 9.7--101 $\rm /yr/Gpc^3$. These Pop III binaries might contribute to some part of the massive BBH gravitational wave (GW) sources detected by aLIGO/aVIRGO. We also calculated the redshift dependence of Pop III BBH mergers. We found that Pop III low spin BBHs tend to merge at low redshift, while Pop III high spin BBHs do at high redshift, which can be confirmed by future GW detectors such as ET, CE, and DECIGO. These detectors can also check the redshift dependence of BBH merger rate and spin distribution. Our results show that except for one model, the mean effective spin $\left\langle \chi_{\rm eff} \right\rangle$ at $z=0$ ranges $0.02$--$0.3$ while at $z=10$ it does $0.16$--$0.64$. Therefore, massive stellar-mass BBH detection by GWs will be a key for the stellar evolution study in the early universe.

[24]  arXiv:2005.09808 [pdf, other]

Title: A Sequential Generalized Likelihood Ratio Test for Signal Detection from Photon Counting Images

Authors: Mengya Hu, He Sun, Anthony Harness, N. Jeremy Kasdin

Comments: 9 pages, 6 figures, submitted to Optics Express

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Image and Video Processing (eess.IV); Signal Processing (eess.SP)

Exoplanets are very dim. An Electron Multiplying Charged Coupled Device (EMCCD) operating in photon counting (PC) mode reduces the noise level and enables their detection. Typically, PC images are added together as a co-added image before processing. We present here a signal detection and estimation technique working directly with the PC images. The method is based on the generalized maximum likelihood ratio test (GLRT) and uses a binomial distribution between PC images. It can be applied online, so it is possible to stop observations once we have reached a threshold confidence for the existence (or absence) of planets, and thus the observation time is efficiently used. It directly uses the detector model, which more accurately represents its noise characteristics. We show that it outperforms our previous GLRT method using co-added images under Gaussian noise assumption.

[25]  arXiv:2005.09817 [pdf, other]

Title: Alfvén-wave driven magnetic rotator winds from low-mass stars I: rotation dependences of magnetic braking and mass-loss rate

Authors: Munehito Shoda, Takeru K. Suzuki, Sean P. Matt, Steven R. Cranmer, Aline A. Vidotto, Antoine Strugarek, Victor See, Victor Réville, Adam J. Finley, Allan Sacha Brun

Comments: accepted for publication in The Astrophysical Journal

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

Observations of stellar rotation show that low-mass stars lose angular momentum during the main sequence. We simulate the winds of Sun-like stars with a range of rotation rates, covering the fast and slow magneto-rotator regimes, including the transition between the two. We generalize an Alfv\'en-wave driven solar wind model that builds on previous works by including the magneto-centrifugal force explicitly. In this model, the surface-averaged open magnetic flux is assumed to scale as $B_\ast f^{\rm open}_\ast \propto {\rm Ro}^{-1.2}$, where $f^{\rm open}_\ast$ and ${\rm Ro}$ are the surface open-flux filling factor and Rossby number, respectively. We find that, 1. the angular momentum loss rate (torque) of the wind is described as $\tau_w \approx 2.59 \times 10^{30} {\rm \ erg} \ \left( \Omega_\ast / \Omega_\odot \right)^{2.82}$, yielding a spin-down law $\Omega_\ast \propto t^{-0.55}$. 2. the mass-loss rate saturates at $\dot{M}_w \sim 3.4 \times 10^{-14} M_\odot {\rm \ yr^{-1}}$, due to the strong reflection and dissipation of Alfv\'en waves in the chromosphere. This indicates that the chromosphere has a strong impact in connecting the stellar surface and stellar wind. Meanwhile, the wind ram pressure scales as $P_w \propto \Omega_\ast^{0.57}$, which is able to explain the lower-envelope of the observed stellar winds by Wood et al. 3. the location of the Alfv\'en radius is shown to scale in a way that is consistent with 1D analytic theory. Additionally, the precise scaling of the Alfv\'en radius matches previous works which used thermally-driven winds. Our results suggest that the Alfv\'en-wave driven magnetic rotator wind plays a dominant role in the stellar spin-down during the main-sequence.

[26]  arXiv:2005.09818 [pdf, ps, other]

Title: High-velocity interstellar absorption associated with the supernova remnant W28

Authors: Adam M. Ritchey (Univ. of Washington)

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

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

We present an analysis of moderately high resolution optical spectra obtained for the sight line to CD-23 13777, an O9 supergiant that probes high velocity interstellar gas associated with the supernova remnant W28. Absorption components at both high positive and high negative velocity are seen in the interstellar Na I D and Ca II H and K lines toward CD-23 13777. The high velocity components exhibit low Na I/Ca II ratios, suggesting efficient grain destruction by shock sputtering. High column densities of CH+, and high CH+/CH ratios, for the components seen at lower velocity may be indicative of enhanced turbulence in the clouds interacting with W28. The highest positive and negative velocities of the components seen in Na I and Ca II absorption toward CD-23 13777 imply that the velocity of the blast wave associated with W28 is at least 150 km/s, a value that is significantly higher than most previous estimates. The line of sight to CD-23 13777 passes very close to a well-known site of interaction between the SNR and a molecular cloud to the northeast. The northeast molecular cloud exhibits broad molecular line emission, OH maser emission from numerous locations, and bright extended GeV and TeV gamma-ray emission. The sight line to CD-23 13777 is thus a unique and valuable probe of the interaction between W28 and dense molecular gas in its environs. Future observations at UV and visible wavelengths will help to better constrain the abundances, kinematics, and physical conditions in the shocked and quiescent gas along this line of sight.

[27]  arXiv:2005.09846 [pdf, ps, other]

Title: Detailed chemical compositions of planet hosting stars: I. Exploration of possible planet signatures

Authors: F. Liu, D. Yong, M. Asplund, H. S. Wang, L. Spina, L. Acuna, J. Melendez, I. Ramirez

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

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

We present a line-by-line differential analysis of a sample of 16 planet hosting stars and 68 comparison stars using high resolution, high signal-to-noise ratio spectra gathered using Keck. We obtained accurate stellar parameters and high-precision relative chemical abundances with average uncertainties in \teff, \logg, [Fe/H] and [X/H] of 15 K, 0.034 [cgs], 0.012 dex and 0.025 dex, respectively. For each planet host, we identify a set of comparison stars and examine the abundance differences (corrected for Galactic chemical evolution effect) as a function of the dust condensation temperature, \tcond, of the individual elements. While we confirm that the Sun exhibits a negative trend between abundance and \tcond, we also confirm that the remaining planet hosts exhibit a variety of abundance $-$ \tcond\ trends with no clear dependence upon age, metallicity or \teff. The diversity in the chemical compositions of planet hosting stars relative to their comparison stars could reflect the range of possible planet-induced effects present in these planet hosts, from the sequestration of rocky material (refractory poor), to the possible ingestion of planets (refractory rich). Other possible explanations include differences in the timescale, efficiency and degree of planet formation or inhomogeneous chemical evolution. Although we do not find an unambiguous chemical signature of planet formation among our sample, the high-precision chemical abundances of the host stars are essential for constraining the composition and structure of their exoplanets.

[28]  arXiv:2005.09853 [pdf, other]

Title: SDSS-IV MaNGA: the role of bars in central star formation enhancements

Authors: Lin Lin, Cheng Li, Cheng Du, Enci Wang, Ting Xiao, Martin Bureau, Amelia Fraser-McKelvie, Karen Masters, Lihwai Lin, David Wake, Lei Hao

Comments: 17 pages, 9 figures, submitted to MNRAS

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

We analyse two-dimensional maps and radial profiles of the equivalent width of H$\alpha$ emission (EW(H$\alpha$)), H$\delta$ absorption (EW(H$\delta_A$)), and the 4000\AA\ break (D$_n$(4000)) of low-redshift galaxies using integral field spectroscopy from the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey. Out of $\approx2400$ nearly face-on galaxies with a redshift $z<0.05$ from the MaNGA Products Launch 7, we identify 124 "turnover" galaxies that each have a central upturn in EW(H$\alpha$), EW(H$\delta_A$) and/or a central drop in D$_n$(4000), indicative of ongoing/recent star formation (SF). The turnover features are found mostly in galaxies with a stellar mass above $\sim$10$^{10}$ M$_{\odot}$ and NUV-$r$ colour less than $\approx5$. The majority of the turnover galaxies are barred, with a bar fraction of 87$\pm$3\%. Furthermore, for barred galaxies the radius of the central turnover region ($R_{\rm{t}}$) is found to tightly correlate with the bar length ($R_{\rm{bar}}$): $R_{\rm{t}}$ = (0.35$\pm$0.02)$R_{\rm{bar}}$ + (0.61$\pm$0.13). Comparing the observed and the inward extrapolated star formation rate surface density ($\Sigma_{\rm SFR}$), we estimate that the central SF rate have been enhanced by an order of magnitude. Conversely, only half of the barred galaxies in our sample have a central turnover feature, implying that the presence of a bar is not sufficient to lead to a central SF enhancement. We further examined the SF enhancement in paired galaxies, as well as the density of the local environment, finding no relation. This implies that environment is not a driving factor for central turnover and SF enhancement in our sample galaxies.

[29]  arXiv:2005.09875 [pdf, other]

Title: A Solar Magnetic-fan Flaring Arch Heated by Non-thermal Particles and Hot Plasma from an X-ray Jet Eruption

Authors: Kyoung-Sun Lee, Hirohisa Hara, Kyoko Watanabe, Anand D. Joshi, David H. Brooks, Shinsuke Imada, Avijeet Prasad, Phillip Dang, Toshifumi Shimizu, Sabrina L. Savage, Ronald Moore, Navdeep K. Panesar, Jeffrey W. Reep

Comments: 55 pages, 21 Figures, accepted for publication in ApJ

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

We have investigated an M1.3 limb flare, which develops as a magnetic loop/arch that fans out from an X-ray jet. Using Hinode/EIS, we found that the temperature increases with height to a value of over 10$^{7}$ K at the loop-top during the flare. The measured Doppler velocity (redshifts of 100$-$500 km s$^{-1}$) and the non-thermal velocity ($\geq$100 km s$^{-1}$) from Fe XXIV also increase with loop height. The electron density increases from $0.3\times10^{9}$ cm$^{-3}$ early in the flare rise to $1.3\times10^{9}$ cm$^{-3}$ after the flare peak. The 3-D structure of the loop derived with STEREO/EUVI indicates that the strong redshift in the loop-top region is due to upflowing plasma originating from the jet. Both hard X-ray and soft X-ray emission from RHESSI were only seen as footpoint brightenings during the impulsive phase of the flare, then, soft X-ray emission moves to the loop-top in the decay phase. Based on the temperature and density measurements and theoretical cooling models, the temperature evolution of the flare arch is consistent with impulsive heating during the jet eruption followed by conductive cooling via evaporation and minor prolonged heating in the top of the fan loop. Investigating the magnetic field topology and squashing factor map from SDO/HMI, we conclude that the observed magnetic-fan flaring arch is mostly heated from low atmospheric reconnection accompanying the jet ejection, instead of from reconnection above the arch as expected in the standard flare model.

[30]  arXiv:2005.09895 [pdf, other]

Title: Jupiter in the ultraviolet: acetylene and ethane abundances in the stratosphere of Jupiter from Cassini observations between 0.15 and 0.19 $μ$m

Authors: Henrik Melin, Leigh N. Fletcher, Pat G. J. Irwin, Scott G Edgington

Comments: Accepted for publication in The Astronomical Journal 28 pages, 23 figures, 3 tables

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

At wavelengths between 0.15 and 0.19 $\mu$m, the far-ultraviolet spectrum of Jupiter is dominated by the scattered solar spectrum, attenuated by molecular absorptions primarily by acetylene and ethane, and to a lesser extent ammonia and phosphine. We describe the development of our radiative transfer code that enables the retrieval of abundances of these molecular species from ultraviolet reflectance spectra. As a proof-of-concept we present an analysis of Cassini Ultraviolet Imaging Spectrograph (UVIS) observations of the disk of Jupiter during the 2000/2001 flyby. The ultraviolet-retrieved acetylene abundances in the upper stratosphere are lower than those predicted by models based solely on infrared thermal emission from the mid-stratosphere observed by the Composite Infrared Spectrometer (CIRS), requiring an adjustment to the vertical profiles above 1 mbar. We produce a vertical acetylene abundance profile that is compatible with both CIRS and UVIS, with reduced abundances at pressures $<$1 mbar: the 0.1 mbar abundances are $1.21 \pm 0.07$ ppm for acetylene and $20.8 \pm 5.1$ ppm for ethane. Finally, we perform a sensitivity study for the JUICE UVS instrument, which has extended wavelength coverage out to 0.21 nm, enabling the retrieval of ammonia and phosphine abundances, in addition to acetylene and ethane.

[31]  arXiv:2005.09896 [pdf, other]

Title: The Three Hundred project: shapes and radial alignment of satellite, infalling, and backsplash galaxies

Authors: Alexander Knebe, Matias Gamez-Marin, Frazer R. Pearce, Weiguang Cui, Kai Hoffmann, Marco De Petris, Chris Power, Roan Haggar, Robert Mostoghiu

Comments: 14 pages, accepted for publication in MNRAS

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

Using 324 numerically modelled galaxy clusters we investigate the radial and galaxy-halo alignment of dark matter subhaloes and satellite galaxies orbiting within and around them. We find that radial alignment depends on distance to the centre of the galaxy cluster but appears independent of the dynamical state of the central host cluster. Furthermore, we cannot find a relation between radial alignment of the halo or galaxy shape with its own mass. We report that backsplash galaxies, i.e. objects that have already passed through the cluster radius but are now located in the outskirts, show a stronger radial alignment than infalling objects. We further find that there exists a population of well radially aligned objects passing very close to the central cluster's centre which were found to be on highly radial orbit.

[32]  arXiv:2005.09911 [pdf, other]

Title: Characterizing Some Gaia Alerts with LAMOST and SDSS

Authors: Z. Huo, M. Dennefeld, X. Liu, T. Pursimo, T. Zhang

Comments: Accepted for publication in APSS, 14 pages, 8 figures, 2 tables

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

Gaia is regularly producing Alerts on objects where photometric variability has been detected. The physical nature of these objects has often to be determined with the complementary observations from ground-based facilities. We have compared the list of Gaia Alerts (until 20181101) with archival LAMOST and SDSS spectroscopic data. The date of the ground-based observation rarely corresponds to the date of the Alert, but this allows at least the identification of the source if it is persistent, or the host galaxy if the object was only transient like a supernova. A list of Gaia Nuclear Transients from Kostrzewa-Rutkowska et al. (2018) has been included in this search also. We found 26 Gaia Alerts with spectra in LAMOST+SDSS labelled as stars (12 with multi-epoch spectra). A majority of them are CVs. Similarly 206 Gaia Alerts have associated spectra labelled as galaxies (49 with multi-epoch spectra). Those spectra were generally obtained on a date different from the Alert date, are mostly emission-line galaxies, leading to the suspicion that most of the Alerts were due to a SN. As for the GNT list, we found 55 associated spectra labelled as galaxies (13 with multi-epoch spectra). In two galaxies, Gaia17aal and GNTJ170213+2543, was the date of the spectroscopic observation close enough to the Alert date: we find a trace of the SN itself in their LAMOST spectrum, both classified here as a type Ia SN. The GNT sample has a higher proportion of AGNs, suggesting that some of the detected variations are also due to the AGN itself. Similar for Quasars, we found 30 Gaia Alerts but 68 GNT cases have single epoch quasar spectra, while 12 plus 23 have multi-epoch spectra. For ten out of these 35, their multi-epoch spectra show appearance or disappearance of the broad Balmer lines and also variations in the continuum, qualifying them as "Changing Look Quasars".

[33]  arXiv:2005.09920 [pdf, ps, other]

Title: First day of type IIP supernova SN 2013fs: H$α$ from preshock accelerated gas

Authors: Nikolai Chugai

Comments: accepted by Astronomy Letters

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

I explore the origin of an asymmetry of the H$\alpha$ emission from a circumstellar (CS) shell around type IIP supernova SN 2013fs in the spectrum taken 10.3\,h after the shock breakout. A spherical model of the H$\alpha$ emission from the CS shell that takes into account a preshock gas acceleration by the supernova radiation permits us to successfully reproduce the \ha H$\alpha$ profile. Principal factors responsible for the H$\alpha$ asymmetry are the high velocity of the accelerated CS preshock gas ($\sim 3000$\,km s$^{-1}$) and a low H$\alpha$ Sobolev optical depth in a combination with an occultation of the H$\alpha$ emission by the photosphere.

[34]  arXiv:2005.09947 [pdf, ps, other]

Title: Asteroid models from generalised projections: Essential facts for asteroid modellers and geometric inverse problem solvers

Authors: Mikko Kaasalainen, Josef Durech

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

We present a review of the problem of asteroid shape and spin reconstruction from generalised projections; i.e., from lightcurves, disk-resolved images, occultation silhouettes, radar range-Doppler data, and interferometry. The aim of this text is to summarize all important mathematical facts and proofs related to this inverse problem, to describe their implications to observers and modellers, and to provide the reader with all relevant references.

[35]  arXiv:2005.09982 [pdf, other]

Title: Detection of a variable ultra-fast outflow in the Narrow Line Seyfert 1 galaxy PG 1448+273

Authors: P. Kosec, A. Zoghbi, D. J. Walton, C. Pinto, A. C. Fabian, M. L. Parker, C. S. Reynolds

Comments: Accepted for publication in MNRAS. 14 pages, 11 figures, 1 table

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

Relativistically blueshifted absorption features of highly ionised ions, the so-called ultra-fast outflows (UFOs), have been detected in the X-ray spectra of a number of accreting supermassive black holes. If these features truly originate from accretion disc winds accelerated to more than 10 per cent of the speed of light, their energy budget is very significant and they can contribute to or even drive galaxy-scale feedback from active galactic nuclei (AGN). However, the UFO spectral features are often weak due to high ionisation of the outflowing material, and the inference of the wind physical properties can be complicated by other spectral features in AGN such as relativistic reflection. Here we study a highly accreting Narrow Line Seyfert 1 galaxy PG 1448+273. We apply an automated, systematic routine for detecting outflows in accreting systems and achieve an unambiguous detection of a UFO in this AGN. The UFO absorption is observed in both soft and hard X-ray bands with the XMM-Newton observatory. The velocity of the outflow is (26900 +- 600) km/s (~0.09c), with an ionisation parameter of log ({\xi} / erg cm s^-1)=4.03_{-0.08}^{+0.10} and a column density above 10^23 cm^-2. At the same time, we detect weak warm absorption features in the spectrum of the object. Our systematic outflow search suggests the presence of further multi-phase wind structure, but we cannot claim a significant detection considering the present data quality. The UFO is not detected in a second, shorter observation with XMM-Newton, indicating variability in time, observed also in other similar AGN.

[36]  arXiv:2005.10001 [pdf, ps, other]

Title: Spectral variability of the 3C 390.3 nucleus for more than 20 years -- II. Variability of the broad emission-line profiles and He II $\lambda4686$A emission-line fluxes

Authors: S.G. Sergeev

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

Results of the analysis of the variability of the H$\beta$ and H$\alpha$ broad emission-line profiles and the He II $\lambda4686$A emission-line fluxes in the 3C 390.3 nucleus during 1992-2014 are present. The observed velocity-dependent lag for the Balmer lines is similar to that expected from the Keplerian disc configuration, although there are some differences. Probably, a radial infall motion can be present in the broad-line region of 3C 390.3 in addition to the Keplerian rotation. The lag of the broad He II line is $26\pm 8$d, significantly less than that of the Balmer lines, so the He II emission region is much smaller in size. In terms of the power-law relationship between line and optical continuum fluxes with slowly varying scalefactor $c(t)$: $F_{line}\propto c(t)\,F_{cont}^a$, the power $a$ is $1.03$ for the broad He II line, while according to Paper I the power is equal to $0.77$ and $0.54$ for the broad H$\beta$ and H$\alpha$ lines, respectively. It means that the variability amplitude is the largest in the He II, less in H$\beta$, and more less in H$\alpha$. However, the Balmer lines contain a long-term trend that is not seen in the helium line. The narrow He II line is variable with the amplitude (max-to-min ratio) $R_{max}\approx 3$ that is much greater than the variability amplitudes of both the narrow Balmer lines and the narrow [O III] $\lambda$5007A line.

[37]  arXiv:2005.10014 [pdf, other]

Title: The Local Star Formation Rate Surface Density And Metallicity Relation For Star-forming Galaxies

Authors: Berzaf Berhane Teklu, Yulong Gao, Xu Kong, Zesen Lin, Zhixiong Liang

Comments: Accepted for publication in ApJ

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

We study the relations between gas-phase metallicity ($Z$), local stellar mass surface density ($\Sigma_*$), and the local star formation surface density ($\Sigma_{\rm SFR}$) in a sample of 1120 star-forming galaxies from the MaNGA survey. At fixed $\Sigma_{*}$ the local metallicity increases as decreasing of $\Sigma_{\rm SFR}$ or vice versa for metallicity calibrators of N2 and O3N2. Alternatively, at fixed $\Sigma_{\rm SFR}$ metallicity increases as increasing of $\Sigma_{*}$, but at high mass region, the trend is flatter. However, the dependence of metallicity on $\Sigma_{\rm SFR}$ is nearly disappeared for N2O2 and N2S2 calibrators. We investigate the local metallicity against $\Sigma_{\rm SFR}$ with different metallicity calibrators, and find negative/positive correlations depending on the choice of the calibrator. We demonstrate that the O32 ratio (or ionization parameter) is probably dependent on star formation rate at fixed local stellar mass surface density. Additional, the shape of $\Sigma_*$ -- $Z$ -- $\Sigma_{\rm SFR}$ (FMR) depends on metallicity calibrator and stellar mass range. Since the large discrepancy between the empirical fitting-based (N2, O3N2) to electronic temperature metallicity and the photoionization model-dependent (N2O2, N2S2) metallicity calibrations, we conclude that the selection of metallicity calibration affects the existence of FMR on $\Sigma_{\rm SFR}$.

[38]  arXiv:2005.10031 [pdf, other]

Title: The UV Perspective of Low-Mass Star Formation

Authors: P. C. Schneider, H. M. Günther, K. France

Comments: 26 pages, 12 figures. Published in Galaxies special issue: "Star Formation in the UV", ed. Jorick Vink

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

The formation of low-mass stars in molecular clouds involves accretion disks and jets, which are of broad astrophysical interest. Accreting stars represent the closest examples of these phenomena. Star and planet formation are also intimately connected, setting the starting point for planetary systems like our own. The ultraviolet (UV) spectral range is particularly suited to study star formation, because virtually all relevant processes radiate at temperatures associated with UV emission processes or have strong observational signatures in the UV. In this review, we describe how UV observations provide unique diagnostics for the accretion process, the physical properties of the protoplanetary disk, and jets and outflows.

[39]  arXiv:2005.10037 [pdf, ps, other]

Title: Stellar mass Primordial Black Holes as Cold Dark Matter

Authors: J. L. G. Sobrinho, P. Augusto

Comments: 7 pages, 4 figures and 2 tables

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

Primordial Black Holes (PBHs) might have formed in the early Universe due to the collapse of density fluctuations. PBHs may act as the sources for some of the gravitational waves recently observed. We explored the formation scenarios of PBHs of stellar mass, taking into account the possible influence of the QCD phase transition, for which we considered three different models: Crossover Model (CM), Bag Model (BM), and Lattice Fit Model (LFM). For the fluctuations, we considered a running-tilt power-law spectrum; when these cross the $\sim 10^{-9}$-$10^{-1}\mathrm{~s}$ Universe horizon they originate 0.05-500~M$_{\odot}$ PBHs which could: i) provide a population of stellar mass PBHs similar to the ones present on the binaries associated with all known gravitational wave sources; ii) constitute a broad mass spectrum accounting for $\sim 76\%$ of all Cold Dark Matter (CDM) in the Universe.

[40]  arXiv:2005.10077 [pdf, other]

Title: Characterising brown dwarf companions with IRDIS long-slit spectroscopy: HD 1160 B and HD 19467 B

Authors: D. Mesa, V. D'Orazi, A. Vigan, D. Kitzmann, K. Heng, R. Gratton, S. Desidera, M. Bonnefoy, B. Lavie, A.-L. Maire, S. Peretti, A. Boccaletti

Comments: 14 pages, 14 Figures. Accepted for publication on MNRAS

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

The determination of the fundamental properties (mass, separation, age, gravity and atmospheric properties) of brown dwarf companions allows us to infer crucial informations on their formation and evolution mechanisms. Spectroscopy of substellar companions is available to date only for a limited number of objects (and mostly at very low resolution, R<50) because of technical limitations, i.e., contrast and angular resolution. We present medium resolution (R=350), coronagraphic long-slit spectroscopic observations with SPHERE of two substellar companions, HD 1160 B and HD 19467 B. We found that HD 1160 B has a peculiar spectrum that cannot be fitted by spectra in current spectral libraries. A good fit is possible only considering separately the Y+J and the H spectral band. The spectral type is between M5 and M7. We also estimated a T_eff of 2800-2900 K and a log(g) of 3.5-4.0 dex. The low surface gravity seems to favour young age (10-20 Myr) and low mass (~20 M Jup ) for this object. HD 19467 B is instead a fully evolved object with a T_eff of ~1000 K and log g of ~5.0 dex. Its spectral type is T6+/-1.

[41]  arXiv:2005.10096 [pdf, other]

Title: A Survey for New Stars and Brown Dwarfs in the Ophiuchus Star-forming Complex

Authors: T. L. Esplin, K. L. Luhman

Comments: 8 Pages, 10 figures, accepted in AJ, machine readable tables available at this https URL

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

We have performed a survey for new members of the Ophiuchus cloud complex using high-precision astrometry from the second data release of Gaia, proper motions measured with multi-epoch images from the Spitzer Space Telescope, and color-magnitude diagrams constructed with photometry from various sources. Through spectroscopy of candidates selected with those data, we have identified 155 new young stars. Based on available measurements of kinematics, we classify 102, 47, and six of those stars as members of Ophiuchus, Upper Sco, and other populations in Sco-Cen, respectively. We have also assessed the membership of all other stars in the vicinity of Ophiuchus that have spectroscopic evidence of youth from previous studies, arriving at a catalog of 373 adopted members of the cloud complex. For those adopted members, we have compiled mid-IR photometry from Spitzer and the Wide-field Infrared Survey Explorer} and have used mid-IR colors to identify and classify circumstellar disks. We find that 210 of the members show evidence of disks, including 48 disks that are in advanced stages of evolution. Finally, we have estimated the relative median ages of the populations near the Ophiuchus clouds and the surrounding Upper Sco association using absolute K-band magnitudes (M_K) based on Gaia} parallaxes. If we adopt an age 10 Myr for Upper Sco, then the relative values of M_K imply median ages of ~2 Myr for L1689 and embedded stars in L1688, 3-4 Myr for low-extinction stars near L1688, and ~6 Myr for the group containing rho Oph.

[42]  arXiv:2005.10105 [pdf, other]

Title: The correlation between photometric variability and radial velocity jitter, based on TESS and HARPS observations

Authors: S. Hojjatpanah, M. Oshagh, P. Figueira, N.C. Santos, E. M. Amazo-Gómez, S. G. Sousa, V. Adibekyan, B. Akinsanmi, O. Demangeon, J. Faria, J. Gomes da Silva, N. Meunier

Comments: Accepted for publication in section 10. Planets and planetary systems of A&A

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

The current and upcoming high precision photometric surveys such as TESS, CHEOPS, and PLATO will provide the community with thousands of new exoplanet candidates. As a consequence, the presence of such a correlation is crucial in selecting the targets with the lowest RV jitter for efficient RV follow-up of exoplanetary candidates. Studies of this type are also crucial to design optimized observational strategies to mitigate RV jitter when searching for Earth-mass exoplanets. Our goal is to assess the correlation between high-precision photometric variability measurements and high-precision RV jitter over different time scales. We analyze 171 G, K, and M stars with available TESS high precision photometric time-series and HARPS precise RVs. We derived the stellar parameters for the stars in our sample and measured the RV jitter and photometric variability. We also estimated chromospheric Ca II H $\&$ K activity indicator $log(R' _{HK})$, $\textit{v sin i}$, and the stellar rotational period. Finally, we evaluate how different stellar parameters and a RV sampling subset can have an impact on the potential correlations. We find a varying correlation between the photometric variability and RV jitter as function of time intervals between the TESS photometric observation and HARPS RV. As the time intervals of the observations considered for the analysis increases, the correlation value and significance becomes smaller and weaker, to the point that it becomes negligible. We also find that for stars with a photometric variability above 6.5 ppt the correlation is significantly stronger. We show that such a result can be due to the transition between the spot-dominated and the faculae-dominated regime. We quantified the correlations and updated the relationship between chromospheric Ca II H $\&$ K activity indicator $log(R' _{HK})$ and RV jitter.

[43]  arXiv:2005.10108 [pdf, other]

Title: Evolved Massive Stars at Low-metallicity II. Red Supergiant Stars in the Small Magellanic Cloud

Authors: Ming Yang, Alceste Z. Bonanos, Bi-Wei Jiang, Jian Gao, Panagiotis Gavras, Grigoris Maravelias, Shu Wang, Xiao-Dian Chen, Frank Tramper, Yi Ren, Zoi T. Spetsieri, Meng-Yao Xue

Comments: 18 pages, 12 figures, A&A accepted

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

We present the most comprehensive RSG sample for the SMC up to now, including 1,239 RSG candidates. The initial sample is derived based on a source catalog for the SMC with conservative ranking. Additional spectroscopic RSGs are retrieved from the literature, as well as RSG candidates selected from the inspection of CMDs. We estimate that there are in total $\sim$ 1,800 or more RSGs in the SMC. We purify the sample by studying the infrared CMDs and the variability of the objects, though there is still an ambiguity between AGBs and RSGs. There are much less RSGs candidates ($\sim$4\%) showing PAH emission features compared to the Milky Way and LMC ($\sim$15\%). The MIR variability of RSG sample increases with luminosity. We separate the RSG sample into two subsamples ("risky" and "safe") and identify one M5e AGB star in the "risky" subsample. Most of the targets with large variability are also the bright ones with large MLR. Some targets show excessive dust emission, which may be related to previous episodic mass loss events. We also roughly estimate the total gas and dust budget produced by entire RSG population as $\rm \sim1.9^{+2.4}_{-1.1}\times10^{-6}~M_{\odot}/yr$ in the most conservative case. Based on the MIST models, we derive a linear relation between $T_{\rm eff}$ and observed $\rm J-K_S$ color with reddening correction for the RSG sample. By using a constant bolometric correction and this relation, the Geneva evolutionary model is compared with our RSG sample, showing a good agreement and a lower initial mass limit of $\sim$7 $\rm M_\odot $ for the RSG population. Finally, we compare the RSG sample in the SMC and the LMC. Despite the incompleteness of LMC sample in the faint end, the result indicates that the LMC sample always shows redder color (except for the $\rm IRAC1-IRAC2$ and $\rm WISE1-WISE2$ colors due to CO absorption) and larger variability than the SMC sample.

[44]  arXiv:2005.10128 [pdf, other]

Title: Refining the Census of the Upper Scorpius Association with Gaia

Authors: K. L. Luhman, T. L. Esplin

Comments: Astronomical Journal, in press; machine readable tables and fits spectra available at this http URL

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

We have refined the census of stars and brown dwarfs in the Upper Sco association (~10 Myr, ~145 pc) by 1) updating the selection of candidate members from our previous survey to include the high-precision astrometry from the second data release of Gaia, 2) obtaining spectra of a few hundred candidate members to measure their spectral types and verify their youth, and 3) assessing the membership (largely with Gaia astrometry) of 2020 stars toward Upper Sco that show evidence of youth in this work and previous studies. We arrive at a catalog of 1761 objects that are adopted as members of Upper Sco. The distribution of spectral types among the adopted members is similar to those in other nearby star-forming regions, indicating a similar initial mass function. In previous studies, we have compiled mid-infrared photometry from WISE and the Spitzer Space Telescope for members of Upper Sco and used those data to identify the stars that show evidence of circumstellar disks; we present the same analysis for our new catalog of members. As in earlier work, we find that the fraction of members with disks increases with lower stellar masses, ranging from <=10% for >1 Msun to ~22% for 0.01-0.3 Msun. Finally, we have estimated the relative ages of Upper Sco and other young associations using their sequences of low-mass stars in M(G_RP) versus G_BP-G_RP. This comparison indicates that Upper Sco is a factor of two younger than the beta Pic association (21-24 Myr) according to both non-magnetic and magnetic evolutionary models.

[45]  arXiv:2005.10138 [pdf, ps, other]

Title: Exploring formation scenarios for the exomoon candidate Kepler 1625b I

Authors: Ricardo Moraes, Ernesto Vieira Neto

Comments: 14 pages, 9 figures, accepted for publication on MNRAS

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

If confirmed, the Neptune-size exomoon candidate in the Kepler 1625 system will be the first natural satellite outside our Solar System. Its characteristics are nothing alike we know for a satellite. Kepler 1625b I is expected to be as massive as Neptune and to orbit at 40 planetary radii around a ten Jupiter mass planet. Because of its mass and wide orbit, this satellite was firstly thought to be captured instead of formed in-situ. In this work, we investigated the possibility of an in-situ formation of this exomoon candidate. To do so, we performed N-body simulations to reproduce the late phases of satellite formation and use a massive circum-planetary disc to explain the mass of this satellite. Our setups started soon after the gaseous nebula dissipation, when the satellite embryos are already formed. Also for selected exomoon systems we take into account a post-formation tidal evolution. We found that in-situ formation is viable to explain the origin of Kepler 1625b I, even when different values for the star-planet separation are considered. We show that for different star-planet separations the minimum amount of solids needed in the circum-planetary disc to form such a satellite varies, the wider is this separation more material is needed. In our simulations of satellite formation many satellites were formed close to the planet, this scenario changed after the tidal evolution of the systems. We concluded that if the Kepler1625 b satellite system was formed in-situ, tidal evolution was an important mechanism to sculpt its final architecture.

[46]  arXiv:2005.10204 [pdf, other]

Title: Impact of systematics on cosmological parameters from future Galaxy Clusters surveys

Authors: Laura Salvati, Marian Douspis, Nabila Aghanim

Comments: 13 pages, 8 figures

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

Galaxy clusters are a recent cosmological probe. The precision and accuracy of the cosmological parameters inferred from these objects are affected by the knowledge of cluster physics, entering the analysis through the mass-observable scaling relations, and the theoretical description of their mass and redshift distribution, modelled by the mass function. In this work, we forecast the impact of different modelling of these ingredients for clusters detected by future optical and near-IR surveys. We consider the standard cosmological scenario and the case with a time-dependent equation of state for dark energy. We analyse the effect of increasing accuracy on the scaling relation calibration, finding improved constraints on the cosmological parameters. This higher accuracy exposes the impact of the mass function evaluation, which is a subdominant source of systematics for current data. We compare two different evaluations for the mass function. In both cosmological scenarios, the use of different mass functions leads to biases in the parameter constraints. For the $\Lambda$CDM model, we find a $1.6 \, \sigma$ shift in the $(\Omega_m,\sigma_8)$ parameter plane and a discrepancy of $\sim 7 \, \sigma$ for the redshift evolution of the scatter of the scaling relations. For the scenario with a time-evolving dark energy equation of state, the assumption of different mass functions results in a $\sim 8 \, \sigma$ tension in the $w_0$ parameter. These results show the impact, and the necessity for a precise modelling, of the interplay between the redshift evolution of the mass function and of the scaling relations in the cosmological analysis of galaxy clusters.

[47]  arXiv:2005.10212 [pdf, other]

Title: On the maximum stellar rotation to form a black hole without an accompanying luminous transient

Authors: Ariadna Murguia-Berthier, Aldo Batta, Agnieszka Janiuk, Enrico Ramirez-Ruiz, Ilya Mandel, Scott C. Noble, Rosa Wallace Everson

Comments: 9 pages, 5 figures, submitted to ApJ Letters

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

The collapse of a massive star with low angular momentum content is commonly argued to result in the formation of a black hole without an accompanying bright transient. Our goal in this Letter is to understand the flow in and around a newly-formed black hole, involving accretion and rotation, via general relativistic hydrodynamics simulations aimed at studying the conditions under which infalling material can accrete without forming a centrifugally supported structure and, as a result, generate no effective feedback. If the feedback from the black hole is, on the other hand, significant, the collapse would be halted and we suggest that the event is likely to be followed by a bright transient. We find that feedback is only efficient if the specific angular momentum of the infalling material at the innermost stable circular orbit exceeds that of geodesic circular flow at that radius by at least $\approx 20\%$. We use the results of our simulations to constrain the maximal stellar rotation rates of the disappearing massive progenitors PHL293B-LBV and N6946-BH1, and to provide an estimate of the overall rate of disappearing massive stars. We find that about a few percent of single O-type stars with measured rotational velocities are expected to spin below the critical value before collapse and are thus predicted to vanish without a trace.

[48]  arXiv:2005.10226 [pdf, other]

Title: Predicted rates of merging neutron stars in galaxies

Authors: Marta Molero, Paolo Simonetti, Francesca Matteucci, Massimo della Valle

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

In this work, we compute rates of merging neutron stars (MNS) in galaxies of different morphological type, as well as the cosmic MNS rate in a unitary volume of the Universe adopting different cosmological scenarios. Our aim is to provide predictions of kilonova rates for future observations both at low and high redshift. In the adopted galaxy models, we take into account the production of r-process elements either by MNS or core-collapse supernovae. In computing the MNS rates we adopt either a constant total time delay for merging (10 Myr) or a distribution function of such delays. Our main conclusions are: i) the observed present time MNS rate in our Galaxy is well reproduced either with a constant time delay or a distribution function $\propto t^{-1}$. The [Eu/Fe] vs. [Fe/H] relation in the Milky Way can be well reproduced with only MNS, if the time delay is short and constant. If the distribution function of delays is adopted, core-collapse supernovae as are also required. ii) The present time cosmic MNS rate can be well reproduced in any cosmological scenario, either pure luminosity evolution or a typical hierarchical one, and spirals are the main contributors to it. iii) The spirals are the major contributors to the cosmic MNS at all redshifts in hierarchical scenarios. In the pure luminosity evolution scenario, the spirals are the major contributors locally, whereas at high redshift ellipticals dominate. iv) The predicted cosmic MNS rate well agrees with the cosmic rate of short Gamma Ray Bursts if the distribution function of delays is adopted, in a cosmological hierarchical scenario observationally derived. v) Future observations of Kilonovae in ellipticals will allow to disentangle among constant or a distribution of time delays as well as among different cosmological scenarios.

[49]  arXiv:2005.10236 [pdf, other]

Title: Retrograde orbits excess among observable interstellar objects

Authors: Dusan Marceta, Bojan Novakovic

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

In this work we investigate the orbital distribution of interstellar objects (ISOs), observable by the future wide-field National Science Foundation Vera C. Rubin Observatory (VRO). We generate synthetic population of ISOs and simulate their ephemerides over a period of 10 years, in order to select those which may be observed by the VRO, based on the nominal characteristics of this survey. We find that the population of the observable ISOs should be significantly biased in favor of retrograde objects. The intensity of this bias is correlated with the slope of the size-frequency distribution (SFD) of the population, as well as with the perihelion distances. Steeper SFD slopes lead to an increased fraction of the retrograde orbits, and also of the median orbital inclination. On the other hand, larger perihelion distances result in more symmetric distribution of orbital inclinations. We believe that this is a result of the Holetschek effects, which is already suggested to cause observational bias in orbital distribution of long period comets. The most important implication of our findings is that an excess of retrograde orbits depends on the sizes and the perihelion distances. Therefore, the prograde/retrograde orbits ratio and the median inclination of the discovered population could, in turn, be used to estimate the SFD of the underlying true population of ISOs.

[50]  arXiv:2005.10240 [pdf, other]

Title: X-ray irradiation and evaporation of the four young planets around V1298 Tau

Authors: K. Poppenhaeger, L. Ketzer, M. Mallonn

Comments: Accepted for publication in MNRAS. 14 pages

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

Planets around young stars are thought to undergo atmospheric evaporation due to the high magnetic activity of the host stars. Here we report on X-ray observations of V1298 Tau, a young star with four transiting exoplanets. We use X-ray observations of the host star with Chandra and ROSAT to measure the current high-energy irradiation level of the planets, and employ a model for the stellar activity evolution together with exoplanetary mass loss to estimate the possible evolution of the planets. We find that V1298 Tau is X-ray bright with $\log L_X$ [erg/s] $=30.1$ and has a mean coronal temperature of $\approx 9$ MK. This places the star amongst the more X-ray luminous ones at this stellar age. We estimate the radiation-driven mass loss of the exoplanets, and find that it depends sensitively on the possible evolutionary spin-down tracks of the star as well as on the current planetary densities. Assuming the planets are of low density due to their youth, we find that the innermost two planets can lose significant parts of their gaseous envelopes, and could be evaporated down to their rocky cores depending on the stellar spin evolution. However, if the planets are heavier and follow the mass-radius relation of older planets, then even in the highest XUV irradiation scenario none of the planets is expected to cross the radius gap into the rocky regime until the system reaches an age of 5 Gyr.

Cross-lists for Thu, 21 May 20

[51]  arXiv:2005.09688 (cross-list from hep-th) [pdf, other]

Title: Entanglement Entropy of Cosmological Perturbations

Authors: Suddhasattwa Brahma, Omar Alaryani, Robert Brandenberger

Comments: 18 pages; comments welcome

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

We show that the entropy of cosmological perturbations originating as quantum vacuum fluctuations in the very early universe, including the contribution of the leading nonlinear interactions, can be viewed as momentum space entanglement entropy between sub- and super-Hubble modes. The interactions between these modes causes decoherence of the super-Hubble fluctuations which, in turn, leads to a non-vanishing entropy of the reduced density matrix corresponding to the super-Hubble inhomogeneities. In particular, applying this to inflationary cosmology reveals that the entanglement entropy produced by leading order nonlinearities dominates over that coming from the squeezing of the vacuum state unless inflation lasts for a very short period. Furthermore, demanding that this entanglement entropy be smaller than the thermal entropy at the beginning of the radiation phase of standard cosmology leads to an upper bound on the duration of inflation which is similar to what is obtained from the Trans-Planckian Censorship Conjecture.

[52]  arXiv:2005.09728 (cross-list from gr-qc) [pdf, other]

Title: Core collapse in massive scalar-tensor gravity

Authors: Roxana Rosca-Mead, Ulrich Sperhake, Christopher J. Moore, Michalis Agathos, Davide Gerosa, Christian D. Ott

Comments: 26 pages, 19 figures, submitted to PRD

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

This paper provides an extended exploration of the inverse-chirp gravitational-wave signals from stellar collapse in massive scalar-tensor gravity reported in [Phys. Rev. Lett. {\bf 119}, 201103]. We systematically explore the parameter space that characterizes the progenitor stars, the equation of state and the scalar-tensor theory of the core collapse events. We identify a remarkably simple and straightforward classification scheme of the resulting collapse events. For any given set of parameters, the collapse leads to one of three end states, a weakly scalarized neutron star, a strongly scalarized neutron star or a black hole, possibly formed in multiple stages. The latter two end states can lead to strong gravitational-wave signals that may be detectable in present continuous-wave searches with ground-based detectors. We identify a very sharp boundary in the parameter space that separates events with strong gravitational-wave emission from those with negligible radiation.

[53]  arXiv:2005.09750 (cross-list from physics.ins-det) [pdf]

Title: Spectrum-free integrated photonic remote molecular identification and sensing

Authors: Ross Cheriton, Suresh Sivanandam, Adam Densmore, Ernst J. W. de Mooij, Daniele Melati, Mohsen Kamandar Dezfouli, Pavel Cheben, Danxia Xu, Jens H. Schmid, Jean Lapointe, Rubin Ma, Shurui Wang, Luc Simard, Siegfried Janz

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

Absorption spectroscopy is widely used in sensing and astronomy to understand molecular compositions on microscopic to cosmological scales. However, typical dispersive spectroscopic techniques require multichannel detection, fundamentally limiting the ability to detect extremely weak signals when compared to direct photometric methods. We report the realization of direct spectral molecular detection using a silicon nanophotonic waveguide resonator, obviating dispersive spectral acquisition. We use a thermally tunable silicon ring resonator with a transmission spectrum matched and cross-correlated to the quasi-periodic vibronic absorption lines of hydrogen cyanide. We show that the correlation peak amplitude is proportional to the number of overlapping ring resonances and gas lines, and that molecular specificity is obtained from the phase of the correlation signal in a single detection channel. Our results demonstrate on-chip correlation spectroscopy that is less restricted by the signal-to-noise penalty of other spectroscopic approaches, enabling the detection of faint spectral signatures.

[54]  arXiv:2005.09919 (cross-list from physics.ins-det) [pdf]

Title: Measurement of the Background Activities of a 100Mo-enriched powder sample for AMoRE crystal material using a single high purity germanium detector

Authors: Su-yeon Park, Insik Hahn, Woon Gu Kang, Gowoon Kim, Eun Kyung Lee, Douglas S. Leonard, Vladimir Kazalov, Yeong Duk Kim, Moo Hyun Lee, Elena Sala

Comments: 19 pages, 6 figures

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

The Advanced Molybdenum-based Rare process Experiment (AMoRE) searches for neutrino-less double-beta (0{\nu}\b{eta}\b{eta}) decay of 100Mo in enriched molybdate crystals. The AMoRE crystals must have low levels of radioactive contamination to achieve a low rate of background signals with energies near the Q-value of 100Mo 0{\nu}\b{eta}\b{eta} decay. To produce low-activity crystals, radioactive contaminants in the raw materials used to form the crystals must be controlled and quantified. 100EnrMoO3 powder, which is enriched in the 100Mo isotope, is of particular interest as it is the source of 100Mo in the crystals. A high-purity germanium detector having 100% relative efficiency, named CC1, is being operated in the Yangyang underground laboratory. Using CC1, we collected a gamma spectrum from a 1.6 kg 100EnrMoO3 powder sample, enriched to 96.4% in 100Mo. Activities were analyzed for the isotopes 228Ac, 228Th, 226Ra, and 40K, long-lived naturally occurring isotopes that can produce background signals in the region of interest for AMoRE. Activities of both 228Ac and 228Th were < 1.0 mBq/kg at 90% C.L. The activity of 226Ra was measured to be 5.1 {\pm} 0.4 (stat) {\pm} 2.2 (syst) mBq/kg. The 40K activity was found as < 16.4 mBq/kg at 90% C.L.

[55]  arXiv:2005.10075 (cross-list from hep-th) [pdf, other]

Title: Dark energy, Ricci-nonflat spaces, and the Swampland

Authors: Luis A. Anchordoqui, Ignatios Antoniadis, Dieter Lust, Jorge F. Soriano

Comments: 5 pages revtex, two figures

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

It was recently pointed out that the existence of dark energy imposes highly restrictive constraints on effective field theories that satisfy the Swampland conjectures. We provide a critical confrontation of these constraints with the cosmological framework emerging from the Salam-Sezgin model and its string realization by Cvetic, Gibbons, and Pope. We also discuss the implication of the constraints for string model building.

[56]  arXiv:2005.10133 (cross-list from gr-qc) [pdf, ps, other]

Title: Generalization of cosmological attractor approach to Einstein-Gauss-Bonnet gravity

Authors: E.O. Pozdeeva

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

We construct models with the Gauss-Bonnet term multiplied to a function of the scalar field leading to inflationary scenario. The consideration is related with the slow-roll approximation. The cosmological attractor approach gives the spectral index of scalar perturbations which is in a good agreement with modern observation and allows variability for tensor-to-scalar ratio. We reconstruct models with variability of parameters which allow to reproduce cosmological attractor predictions for inflationary parameters in the leading order of $1/N$ approximation in the Einstein-Gauss-Bonnet gravity.

[57]  arXiv:2005.10168 (cross-list from hep-th) [pdf, other]

Title: Dark Energy in String Theory

Authors: Bruno Valeixo Bento, Dibya Chakraborty, Susha L. Parameswaran, Ivonne Zavala

Comments: 23 pages, 4 figures, 3 tables, contribution to the proceedings of the Corfu Summer Institute 2019 "School and Workshops on Elementary Particle Physics and Gravity (CORFU2019)", includes work published in arXiv:1810.08634 (Olguin-Trejo, SLP, Tasinato, IZ) and arXiv:1907.10141 (Hardy, SLP), and some new results

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)

We consider various candidates for Dark Energy, motivated by string theory. Several no-go theorems push de Sitter string vacua, with $w=-1$, to the limits of theoretical control, and all known examples depend on a delicate interplay between different string theoretic ingredients. On the other hand, runaway moduli directions are ubiquitous in string theory, and could plausibly source slow-roll quintessence. We consider various candidate supergravity potentials, motivated by string theory, including single-field K\"ahler potentials for bulk and local moduli, and leading superpotentials of the form $W = W_0 + A e^{-a \Phi}$ or $W = W_0 + A \Phi^p$. Conditions on the scalar potential imposed by supergravity are very restrictive, ruling out e.g. quintessence with $K=-n\ln(\Phi+\bar{\Phi})$ and $W = W_0+A \Phi^p$. Out of the examples considered, one can simultaneously satisfy $V>0$ and $\epsilon_V<1$ only for a deformation-like modulus with $K = k_0 + \frac{|\Phi|^{2n}}{k1}$ and a blow-up like modulus with $K=k_0 +\frac{(\Phi+\bar{\Phi})^{2n}}{k_1}$ when the leading order in the perturbative superpotential, $p$, is equal to $n$. We also review the scenario of Thermal Dark Energy, where thermal effects in a light hidden sector hold a scalar field up away from the minimum of its zero-temperature potential. This provides a viable model of Dark Energy with $w=-1$, consistent with known swampland conjectures, and motivates further early Thermal Dark Energy epochs with potentially observable consequences.

[58]  arXiv:2005.10218 (cross-list from nucl-th) [pdf, other]

Title: Chirally improved quark Pauli blocking in nuclear matter and applications to quark deconfinement in neutron stars

Authors: David Blaschke, Hovik Grigorian, Gerd Röpke

Comments: 19 pages, 12 figures, 3 tables

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

The relativistic mean field (RMF) model of the nuclear matter equation of state has been modified by including the effect of Pauli-blocking owing to quark exchange between the baryons. Different schemes of a chiral enhancement of the quark Pauli blocking have been suggested according to the adopted density dependence of the dynamical quark mass. The resulting equations of state for the pressure are compared to the RMF model DD2 with excluded volume correction. On the basis of this comparison a density-dependent nucleon volume is extracted which parametrises the quark Pauli blocking effect in the respective scheme of chiral enhancement. The dependence on the isospin asymmetry is investigated and the corresponding density dependent nuclear symmetry energy is obtained in fair accordance with phenomenological constraints. The deconfinement phase transition is obtained by a Maxwell construction with a quark matter phase described within a higher order NJL model. Solutions for rotating and nonrotating (hybrid) compact star sequences are obtained which show the effect of high-mass twin compact star solutions for the rotating case.

[59]  arXiv:2005.10238 (cross-list from physics.plasm-ph) [pdf, other]

Title: A family of Vlasov-Maxwell equilibrium distribution functions describing a transition from the Harris sheet to the force-free Harris sheet

Authors: T. Neukirch, F. Wilson, O. Allanson

Comments: 13 pages, 6 figures, accepted by Journal of Plasma Physics

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

We discuss a family of Vlasov-Maxwell equilibrium distribution functions for current sheet equilibria that are intermediate cases between the Harris sheet and the force-free (or modified) Harris sheet. These equilibrium distribution functions have potential applications to space and astrophysical plasmas. The existence of these distribution function had been briefly discussed in by Harrison and Neukirch 2009, but here it is shown that their approach runs into problems in the limit where the guide field goes to zero. The nature of this problem will be discussed and an alternative approach will be suggested that avoids the problem. This is achieved by considering a slight variation of the magnetic field profile, which allows a smooth transition between the Harris and force-free Harris sheet cases.

[60]  arXiv:2005.10239 (cross-list from hep-th) [pdf, other]

Title: Revisiting relativistic magnetohydrodynamics from quantum electrodynamics

Authors: Masaru Hongo, Koichi Hattori

Comments: 46 pages, 4 figures

Subjects: High Energy Physics - Theory (hep-th); High Energy Astrophysical Phenomena (astro-ph.HE); Statistical Mechanics (cond-mat.stat-mech); Nuclear Theory (nucl-th)

We provide a statistical mechanical derivation of relativistic magnetohydrodynamics on the basis of the $(3+1)$-dimensional quantum electrodynamics; the system endowed with the magnetic one-form symmetry. The conservation laws and the constitutive relations are presented in a manifestly covariant way with respect to the general coordinate transformation. The method of the local Gibbs ensemble (or nonequilibrium statistical operator) combined with the path-integral formula for the thermodynamic functional enables us to obtain an exact form of the constitutive relations. Applying the derivative expansion to the exact formula, we derive the first-order constitutive relations for the relativistic magnetohydrodynamics. The result for the QED plasma preserving the parity and charge-conjugation symmetries is equipped with two electrical resistivities and five (three bulk and two shear) viscosities. We also show that those transport coefficients satisfy the Onsager's reciprocal relation and a set of inequalities, indicating the semi-positivity of the entropy production rate consistent with the local second law of thermodynamics.

Replacements for Thu, 21 May 20

[61]  arXiv:1903.06107 (replaced) [pdf, other]

Title: A super-Earth and two sub-Neptunes transiting the nearby and quiet M dwarf TOI-270

Authors: Maximilian N. Günther, Francisco J. Pozuelos, Jason A. Dittmann, Diana Dragomir, Stephen R. Kane, Tansu Daylan, Adina D. Feinstein, Chelsea Huang, Timothy D. Morton, Andrea Bonfanti, L. G. Bouma, Jennifer Burt, Karen A. Collins, Jack J. Lissauer, Elisabeth Matthews, Benjamin T. Montet, Andrew Vanderburg, Songhu Wang, Jennifer G. Winters, George R. Ricker, Roland K. Vanderspek, David W. Latham, Sara Seager, Joshua N. Winn, Jon M. Jenkins, James D. Armstrong, Khalid Barakoui, Natalie Batalha, Jacob L. Bean, Douglas A. Caldwell, David R. Ciardi, Kevin I. Collins, Ian Crossfield, Michael Fausnaugh, Gabor Furesz, Tianjun Gan, Michaël Gillon, Natalia Guerrero, Keith Horne, Steve B. Howell, Michael Ireland, Giovanni Isopi, Emmanuël Jehin, John F. Kielkopf, Sebastien Lepine, Franco Mallia, et al. (14 additional authors not shown)

Comments: Published in Nature Astronomy, 3, 1099. 35 pages, 10 figures, 5 tables. This is the authors' version of the manuscript

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

[62]  arXiv:1903.10849 (replaced) [pdf, other]

Title: The Two Body Problem in the Presence of Dark Energy and Modified Gravity: Application to the Local Group

Authors: Michael McLeod, Ofer Lahav

Comments: 24 pages, 8 figures, 2 tables. Revised to clarify some choices of model parameters

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

[63]  arXiv:1905.08810 (replaced) [pdf, other]

Title: The Thermal History of Composite Dark Matter

Authors: Nicola Andrea Dondi, Francesco Sannino, Juri Smirnov

Comments: Version published in PRD. Comments are welcome!

Journal-ref: Phys. Rev. D 101, 103010 (2020)

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

[64]  arXiv:1906.06641 (replaced) [pdf, other]

Title: Fitting formulae for evolution tracks of massive stars under extreme metal poor environments for population synthesis calculations and star cluster simulations

Authors: Ataru Tanikawa, Takashi Yoshida, Tomoya Kinugawa, Koh Takahashi, Hideyuki Umeda

Comments: 22 pages, 15 figures, 8 tables, accepted for publication in MNRAS

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

[65]  arXiv:1908.05177 (replaced) [pdf, other]

Title: Relativistic reflection spectra of super-spinning black holes

Authors: Biao Zhou, Ashutosh Tripathi, Askar B. Abdikamalov, Dimitry Ayzenberg, Cosimo Bambi, Sourabh Nampalliwar, Menglei Zhou

Comments: 12 pages, 8 figures. v2: refereed version

Journal-ref: Eur. Phys. J. C (2020) 80:400

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

[66]  arXiv:1908.09240 (replaced) [pdf, other]

Title: Thermal Components in Gamma-ray Bursts. II. Constraining the Hybrid Jet Model

Authors: Liang Li

Comments: 32 pages, 13 figures including 94 panels, 1 table, matches the published version in ApJ

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

[67]  arXiv:1909.04262 (replaced) [pdf, ps, other]

Title: ALMA Observations of Giant Molecular Clouds in M33 I: Resolving Star Formation Activities in the Giant Molecular Filaments Possibly Formed by a Spiral Shock

Authors: Kazuki Tokuda, Kazuyuki Muraoka, Hiroshi Kondo, Atsushi Nishimura, Tomoka Tosaki, Sarolta Zahorecz, Sachiko Onodera, Rie E. Miura, Kazufumi Torii, Nario Kuno, Shinji Fujita, Hidetoshi Sano, Toshikazu Onishi, Kazuya Saigo, Yasuo Fukui, Akiko Kawamura, Kengo Tachihara

Comments: 13 pages, 5 figures, Accepted for publication in ApJ

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

[68]  arXiv:1910.05348 (replaced) [pdf, other]

Title: Spikey: Self-Lensing Flares from Eccentric SMBH Binaries

Authors: Betty X. Hu, Daniel J. D'Orazio, Zoltan Haiman, Krista Lynne Smith, Bradford Snios, Maria Charisi, Rosanne Di Stefano

Comments: Accepted to MNRAS

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

[69]  arXiv:1910.05436 (replaced) [pdf, other]

Title: Ca hnk: Calcium-rich Transient SN 2016hnk from the Helium Shell Detonation of a Sub-Chandrasekhar White Dwarf

Authors: Wynn V. Jacobson-Galán, Abigail Polin, Ryan J. Foley, Georgios Dimitriadis, Charles D. Kilpatrick, Raffaella Margutti, David A. Coulter, Saurabh W. Jha, David O. Jones, Robert P. Kirshner, Yen-Chen Pan, Anthony L. Piro, Armin Rest, César Rojas-Bravo

Comments: 33 pages, 18 Figures. Accepted for publication in ApJ

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

[70]  arXiv:1910.06175 (replaced) [pdf, other]

Title: Black hole masses of weak emission line quasars based on continuum fit method

Authors: Marcin Marculewicz, Marek Nikolajuk

Comments: 13 pages, 15 figures, accepted for publication in the Astrophysical Journal

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

[71]  arXiv:1911.00323 (replaced) [pdf, other]

Title: Swampland, Axions and Minimal Warm Inflation

Authors: Suratna Das, Gaurav Goswami, Chethan Krishnan

Comments: v3: Version accepted in Phys. Rev. D

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)

[72]  arXiv:1911.00429 (replaced) [pdf, other]

Title: Quantum-enhanced interferometry for axion searches

Authors: Denis Martynov, Haixing Miao

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

[73]  arXiv:1911.02041 (replaced) [pdf, other]

Title: The impact of quenching on galaxy profiles in the Simba simulation

Authors: Sarah Appleby, Romeel Davé, Katarina Kraljic, Daniel Anglés-Alcázar, Desika Narayanan

Comments: 21 pages, 11 figures, accepted by MNRAS

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

[74]  arXiv:1912.01012 (replaced) [pdf, ps, other]

Title: Non-steady heating of cool cores of galaxy clusters by ubiquitous turbulence and AGN

Authors: Yutaka Fujita, Renyue Cen, Irina Zhuravleva

Journal-ref: MNRAS, 494, 5507-5519 (2020)

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

[75]  arXiv:1912.04296 (replaced) [pdf, other]

Title: A robust estimate of the Milky Way mass from rotation curve data

Authors: Ekaterina V. Karukes, Maria Benito, Fabio Iocco, Roberto Trotta, Alex Geringer-Sameth

Comments: 32 pages, 10 figures, 7 tables, matches published version

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

[76]  arXiv:1912.10210 (replaced) [pdf, other]

Title: Pulsar timing residual induced by ultralight vector dark matter

Authors: Kimihiro Nomura, Asuka Ito, Jiro Soda

Comments: 9 pages, 2 figures

Journal-ref: Eur. Phys. J. C 80, 419 (2020)

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

[77]  arXiv:2001.05519 (replaced) [pdf, other]

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

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

Comments: 11 pages, 10 figures. Accepted for publication in MNRAS

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

[78]  arXiv:2001.10690 (replaced) [pdf, ps, other]

Title: Merger rate density of binary black holes formed in open clusters

Authors: Jun Kumamoto, Michiko S. Fujii, Ataru Tanikawa

Comments: 12 pages, 9 figures, accepted for publication in MNRAS

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

[79]  arXiv:2002.00929 (replaced) [pdf, other]

Title: 3D propagation of relativistic solar protons through interplanetary space

Authors: S. Dalla, G. De Nolfo, A. Bruno, J. Giacalone, T. Laitinen, S. Thomas, M. Battarbee, M.S. Marsh

Comments: Accepted by A&A (revised version, 9 pages, 6 figures)

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

[80]  arXiv:2002.04893 (replaced) [pdf, other]

Title: Lensed or not lensed: Determining lensing magnifications for binary neutron star mergers from a single detection

Authors: Peter T. H. Pang, Otto A. Hannuksela, Tim Dietrich, Giulia Pagano, Ian W. Harry

Comments: 12 pages, 7 figures

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

[81]  arXiv:2002.07991 (replaced) [pdf, other]

Title: Deep learning for intensity mapping observations: Component extraction

Authors: Kana Moriwaki, Nina Filippova, Masato Shirasaki, Naoki Yoshida

Comments: 6 pages, 3 figures, accepted for publication in MNRAS Letter

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

[82]  arXiv:2002.09584 (replaced) [pdf]

Title: Cavity ring-down spectroscopy of CO$_2$ near $λ$ = 2.06 $μ$m: Accurate transition intensities for the Orbiting Carbon Observatory-2 (OCO-2) "strong band"

Authors: Hélène Fleurbaey, Hongming Yi, Erin M. Adkins, Adam J. Fleisher, Joseph T. Hodges

Comments: 34 pages, 10 figures, 4 tables, 54 references

Subjects: Atomic Physics (physics.atom-ph); Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM); Atmospheric and Oceanic Physics (physics.ao-ph); Chemical Physics (physics.chem-ph); Instrumentation and Detectors (physics.ins-det)

[83]  arXiv:2002.10575 (replaced) [pdf, other]

Title: Oscillation of high-energy neutrinos from choked jets in stellar and merger ejecta

Authors: Jose Carpio, Kohta Murase

Comments: 11 pages, 6 figures, accepted for publication in PRD

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

[84]  arXiv:2002.12772 (replaced) [pdf, other]

Title: A Black Hole inside Dark Matter and the Rotation Curves of Galaxies

Authors: Fateen Haddad, Nidal Haddad

Comments: 17 pages, 4 figures, some comments added

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

[85]  arXiv:2003.07375 (replaced) [pdf, other]

Title: Generic searches for alternative gravitational wave polarizations with networks of interferometric detectors

Authors: Peter T. H. Pang, Rico K. L. Lo, Isaac C. F. Wong, Tjonnie G. F. Li, Chris Van Den Broeck

Comments: 8 pages, 3 figures

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

[86]  arXiv:2003.08998 (replaced) [pdf, other]

Title: Evolutionary Models for 43 Galactic Supernova Remnants with Distances and X-ray Spectra

Authors: D.A. Leahy, S. Ranasinghe. M. Gelowitz

Comments: 57 pages, 7 figures, this replacement corrects an error in Section 5.4 on the correction to SNR birthrate and mean energy caused by stellar wind SNRs (the fraction was revised upward from 0.3 to 0.4)

Journal-ref: The Astrophysical Journal Supplement Series, 2020, Volume 248, Issue 1, id.16

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

[87]  arXiv:2003.09046 (replaced) [pdf, other]

Title: Utilizing Small Telescopes Operated by Citizen Scientists for Transiting Exoplanet Follow-up

Authors: Robert T. Zellem, Kyle A. Pearson, Ethan Blaser, Martin Fowler, David R. Ciardi, Anya Biferno, Bob Massey, Franck Marchis, Robert Baer, Conley Ball, Mike Chasin, Mike Conley, Scott Dixon, Elizabeth Fletcher, Saneyda Hernandez, Sujay Nair, Quinn Perian, Frank Sienkiewicz, Kalee Tock, Vivek Vijayakumar, Mark R. Swain, Gael M. Roudier, Geoffrey Bryden, Dennis M. Conti, Dolores H. Hill, Carl W. Hergenrother, Mary Dussault, Stephen R. Kane, Michael Fitzgerald, Pat Boyce, Laura Peticolas, Wilfred Gee, Lynn Cominsky, Rachel Zimmerman-Brachman, Denise Smith, Michelle J. Creech-Eakman, John Engelke, Alexandra Iturralde, Diana Dragomir, Nemanja Jovanovic, Brandon Lawton, Emmanuel Arbouch, Marc Kuchner, Arnaud Malvache

Comments: 26 pages, 15 figures; published in PASP

Journal-ref: Publications of the Astronomical Society of the Pacific, May 2020, Volume 132, Issue 1011, id.054401Publications of the Astronomical Society of the Pacific, Volume 132, Issue 1011, id.054401

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

[88]  arXiv:2004.00031 (replaced) [pdf, other]

Title: Constraints on the circumburst environments of short gamma-ray bursts

Authors: Brendan O'Connor (GWU), Paz Beniamini (Caltech), Chryssa Kouveliotou (GWU)

Comments: 20 pages, 9 figures, accepted for publication in MNRAS

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

[89]  arXiv:2004.00441 (replaced) [pdf, other]

Title: Galactic halo size in the light of recent AMS-02 data

Authors: N. Weinrich, M. Boudaud, L. Derome, Y. Génolini, J. Lavalle, D. Maurin, P. Salati, P. Serpico, G. Weymann-Despres

Comments: 15 pages, 10 figures, 6 tables. Additional references and few clarifications (matches A&A accepted version)

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

[90]  arXiv:2004.04179 (replaced) [pdf, other]

Title: Late X-ray flares from the interaction of a reverse shock with a stratified ejecta in GRB afterglows: simulations on a moving mesh

Authors: Eliot H. Ayache, Hendrik J. van Eerten, Frédéric Daigne

Comments: 17 pages, 22 figures, accepted by MNRAS (18 May 2020)

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

[91]  arXiv:2004.06078 (replaced) [pdf, other]

Title: NS 1987A in SN 1987A

Authors: Dany Page, Mikhail V. Beznogov, Iván Garibay, James M. Lattimer, Madappa Prakash, Hans-Thomas Janka

Comments: 21 pages, 6 figures, to be published in ApJ

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

[92]  arXiv:2004.06622 (replaced) [pdf, other]

Title: Two transiting hot Jupiters from the WASP survey: WASP-150b and WASP-176b

Authors: Benjamin F. Cooke, Don Pollacco, Y. Almleaky, K. Barkaoui, Z. Benkhaldoun, James A. Blake, François Bouchy, Panos Boumis, D. J. A. Brown, Ivan Bruni, A. Burdanov, Andrew Collier Cameron, Paul Chote, A. Daassou, Giuseppe D'ago, Shweta Dalal, Mario Damasso, L. Delrez, A. P. Doyle, E. Ducrot, M. Gillon, G. Hébrard, C. Hellier, Thomas Henning, E. Jehin, Flavien Kiefer, George W. King, Alexios Liakos, Théo Lopez, Luigi Mancini, Rosemary Mardling, P. F. L. Maxted, James McCormac, C. Murray, Louise D. Nielsen, Hugh Osborn, E. Palle, Francesco Pepe, F. J. Pozuelos, J. Prieto-Arranz, D. Queloz, Nicole Schanche, Damien Ségransan, Barry Smalley, John Southworth, S. Thompson, Oliver Turner, Stéphane Udry, S. Velasco, Richard West, Pete Wheatley, John Alikakos

Comments: 15 pages, 14 figures. Accepted for publication in The Astronomical Journal

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

[93]  arXiv:2004.13038 (replaced) [pdf, ps, other]

Title: Evolution and Role of Mergers in the BCG-Cluster Alignment. A View from Cosmological Hydro-Simulations

Authors: Cinthia Ragone-Figueroa, Gian Luigi Granato, Stefano Borgani, Roberto De Propris, Diego Garcia Lambas, Giuseppe Murante, Elena Rasia, Michael West

Comments: 10 pages, 8 figures. MNRAS accepted. Comments welcome

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

[94]  arXiv:2004.14058 (replaced) [pdf, other]

Title: Thermodynamic and Energetic Limits on Continental Silicate Weathering Strongly Impact the Climate and Habitability of Wet, Rocky Worlds

Authors: R.J. Graham, R.T. Pierrehumbert

Comments: 27 pages excluding references, 30 pages total, 8 figures. Submitted to ApJ, accepted 15 May 2020. (reuploaded to arxiv 5/20/2020 to include corresponding author's email address and news of acceptance)

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

[95]  arXiv:2004.14232 (replaced) [pdf, other]

Title: X-Shooter survey of disk accretion in Upper Scorpius I. Very high accretion rates at age>5 Myr

Authors: C.F. Manara, A. Natta, G.P. Rosotti, J.M. Alcala, B. Nisini, G. Lodato, L. Testi, I. Pascucci, L. Hillenbrand, J. Carpenter, A. Scholz, D. Fedele, A. Frasca, G. Mulders, E. Rigliaco, C. Scardoni, E. Zari

Comments: Accepted on Astronomy & Astrophysics. Language edited version

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

[96]  arXiv:2004.14849 (replaced) [pdf, other]

Title: General relativistic Poynting-Robertson effect to diagnose wormholes existence: static and spherically symmetric case

Authors: Vittorio De Falco, Emmanuele Battista, Salvatore Capozziello, Mariafelicia De Laurentis

Comments: 17 pages, 11 figures, 1 Table. Paper accepted on April 30, 2020 on Physical Review D

Journal-ref: Phys. Rev. D 101, 104037, Published 20 May 2020

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

[97]  arXiv:2005.03891 (replaced) [pdf, other]

Title: Measuring elemental abundance ratios in protoplanetary disks at millimeter wavelengths

Authors: D. Fedele (INAF/Arcetri), C. Favre (Univ. Grenoble Alpes)

Comments: Accepted for publication to A&A

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

[98]  arXiv:2005.05054 (replaced) [pdf, other]

Title: The HR 1614 moving group is not a dissolving cluster

Authors: Iryna Kushniruk, Thomas Bensby, Sofia Feltzing, Christian L. Sahlholdt, Diane Feuillet, Luca Casagrande

Comments: Accepted for publication in A&A

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

[99]  arXiv:2005.06388 (replaced) [pdf, other]

Title: The Application of the Filtered Backprojection Algorithm to Solar Rotational Tomography

Authors: Kyuhyoun Cho, Jongchul Chae, Ryun-Young Kwon, Su-Chan Bong, Kyung-Suk Cho

Comments: Accepted for ApJ

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

[100]  arXiv:2005.08252 (replaced) [pdf, ps, other]

Title: Gravitational Focusing of Low-Velocity Dark Matter on the Earth's Surface

Authors: Yoshiaki Sofue

Comments: To appear in Galaxies: special issue on Debate on the Dark Matter; 8 pages, 7 figures

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

[101]  arXiv:2005.08621 (replaced) [pdf, other]

Title: Dark photon dark matter and fast radio bursts

Authors: Ricardo G. Landim

Comments: 7 pages, 2 figures, 1 table, references added, discussion and results updated. Title changed to match updates

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

• New submissions
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• Replacements