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New submissions for Thu, 5 Dec 19

[1]  arXiv:1912.01608 [pdf, other]

Title: Precision of mass and radius determination for neutron star using the ATHENA mission

Authors: A. Majczyna, J. Madej, M. Nalezyty, A. Rozanska, B. Beldycki

Comments: ApJ in print

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

In this paper we show that X-ray spectral observations of the ATHENA mission, which is planned to launch in 2031, can constrain the equation of state of superdense matter. We use our well-constrained continuum fitting method for mass and radius determination of the neutron star. Model spectra of the emission from a neutron star were calculated using the atmosphere code ATM24. In the next step, those models were fitted to a simulated spectra of the neutron star calculated for ATHENA's WFI detector, using the satellite calibration files. To simulate the spectra we assumed three different values of effective temperatures, surface gravities and gravitational redshifts. There cases are related to the three different neutron star masses and radii. This analysis allows us to demonstrate the precision of our method and demonstrate the need for a fast detector onboard of ATHENA. A large grid of theoretical spectra was calculated with various parameters and a hydrogen-helium-iron composition of solar proportion. These spectra were fitted to the simulated spectrum to estimate the precision of mass and radius determination. In each case, we obtained very precise mass and radius values with errors in the range 3--10% for mass and in the range 2--8% for radius within the 1-sigma confidence error. We show here that with the ATHENA WFI detector, such a determination could be used to constrain the equation of state of superdense neutron star matter.

[2]  arXiv:1912.01609 [pdf, other]

Title: Testing exoplanet evaporation with multi-transiting systems

Authors: James Owen, Beatriz Campos Estrada

Comments: Accepted for publication in MNRAS. The software to estimate minimum planet masses is publicly available at: this https URL

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

The photoevaporation model is one of the leading explanations for the evolution of small, close-in planets and the origin of the radius-valley. However, without planet mass measurements, it is challenging to test the photoevaporation scenario. Even if masses are available for individual planets, the host star's unknown EUV/X-ray history makes it difficult to assess the role of photoevaporation. We show that systems with multiple transiting planets are the best in which to rigorously test the photoevaporation model. By scaling one planet to another in a multi-transiting system, the host star's uncertain EUV/X-ray history can be negated. By focusing on systems that contain planets that straddle the radius-valley, one can estimate the minimum-masses of planets above the radius-valley (and thus are assumed to have retained a voluminous hydrogen/helium envelope). This minimum-mass is estimated by assuming that the planet below the radius-valley entirely lost its initial hydrogen/helium envelope, then calculating how massive any planet above the valley needs to be to retain its envelope. We apply this method to 104 planets above the radius gap in 73 systems for which precise enough radii measurements are available. We find excellent agreement with the photoevaporation model. Only two planets (Kepler - 100c & 142c) appear to be inconsistent, suggesting they had a different formation history or followed a different evolutionary pathway to the bulk of the population. Our method can be used to identify TESS systems that warrant radial-velocity follow-up to further test the photoevaporation model.

[3]  arXiv:1912.01610 [pdf, other]

Title: Are Inner Disc Misalignments Common? ALMA Reveals an Isotropic Outer Disc Inclination Distribution for Young Dipper Stars

Authors: M. Ansdell, E. Gaidos, C. Hedges, M. Tazzari, A. L. Kraus, M. C. Wyatt, G. M. Kennedy, J. P. Williams, A. W. Mann, I. Angelo, G. Duchene, E. E. Mamajek, J. Carpenter, T. L. Esplin, A. C. Rizzuto

Comments: Accepted to MNRAS (19 pages, 7 figures, 2 tables)

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

Dippers are a common class of young variable star exhibiting day-long dimmings with depths of up to several tens of percent. A standard explanation is that dippers host nearly edge-on (70 deg) protoplanetary discs that allow close-in (< 1 au) dust lifted slightly out of the midplane to partially occult the star. The identification of a face-on dipper disc and growing evidence of inner disc misalignments brings this scenario into question. Thus we uniformly (re)derive the inclinations of 24 dipper discs resolved with (sub-)mm interferometry from ALMA. We find that dipper disc inclinations are consistent with an isotropic distribution over 0-75 deg, above which the occurrence rate declines (likely an observational selection effect due to optically thick disc midplanes blocking their host stars). These findings indicate that the dipper phenomenon is unrelated to the outer (>10 au) disc resolved by ALMA and that inner disc misalignments may be common during the protoplanetary phase. More than one mechanism may contribute to the dipper phenomenon, including accretion-driven warps and "broken" discs caused by inclined (sub-)stellar or planetary companions.

[4]  arXiv:1912.01611 [pdf, ps, other]

Title: Accretion of a giant planet onto a white dwarf

Authors: Boris T. Gaensicke, Matthias R. Schreiber, Odette Toloza, Nicola P. Gentile Fusillo, Detlev Koester, Christopher J. Manser

Comments: Nature, December 5 issue

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

The detection of a dust disc around G29-38 and transits from debris orbiting WD1145+017 confirmed that the photospheric trace metals found in many white dwarfs arise from the accretion of tidally disrupted planetesimals. The composition of these planetesimals is similar to that of rocky bodies in the inner solar system. Gravitationally scattering planetesimals towards the white dwarf requires the presence of more massive bodies, yet no planet has so far been detected at a white dwarf. Here we report optical spectroscopy of a $\simeq27\,750$K hot white dwarf that is accreting from a circumstellar gaseous disc composed of hydrogen, oxygen, and sulphur at a rate of $\simeq3.3\times10^9\,\mathrm{g\,s^{-1}}$. The composition of this disc is unlike all other known planetary debris around white dwarfs, but resembles predictions for the makeup of deeper atmospheric layers of icy giant planets, with H$_2$O and H$_2$S being major constituents. A giant planet orbiting a hot white dwarf with a semi-major axis of $\simeq15$ solar radii will undergo significant evaporation with expected mass loss rates comparable to the accretion rate onto the white dwarf. The orbit of the planet is most likely the result of gravitational interactions, indicating the presence of additional planets in the system. We infer an occurrence rate of spectroscopically detectable giant planets in close orbits around white dwarfs of $\simeq10^{-4}$.

[5]  arXiv:1912.01612 [pdf, other]

Title: Physical Models for the Clustering of Obscured and Unobscured Quasars

Authors: Kelly E. Whalen (1), Ryan C. Hickox (1), Michael A. DiPompeo (1), Gordon T. Richards (2), Adam D. Myers (3) ((1) Dartmouth College, (2) Drexel University, (3) University of Wyoming)

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

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

Clustering measurements of obscured and unobscured quasars show that obscured quasars reside in more massive dark matter halos than their unobscured counterparts. These results are inconsistent with simple unified (torus) scenarios, but might be explained by models in which the distribution of obscuring material depends on Eddington ratio or galaxy stellar mass. We test these possibilities by constructing simple physical models to compare to observed AGN populations. We find that previously observed relationships between obscuration and Eddington ratio or stellar mass are not sufficient reproduce the observed quasar clustering results ($\langle \log M_{\text{halo}}/M_{\odot} \rangle = 12.94 ^{+ 0.10}_{- 0.11}$ and $\langle \log M_{\text{halo}}/M_{\odot} \rangle = 12.49 ^{+ 0.08}_{- 0.08}$ for obscured and unobscured populations, respectively) while maintaining the observed fraction of obscured quasars (30-65$\%$). This work suggests that evolutionary models, in which obscuration evolves on the typical timescale for black hole growth, are necessary to understand the observed clustering of mid-IR selected quasars.

[6]  arXiv:1912.01615 [pdf, other]

Title: Characterising the i-band variability of YSOs over six orders of magnitude in timescale

Authors: Darryl J. Sergison, Tim Naylor, S. P. Littlefair, Cameron P. M. Bell, C. D. H. Williams

Comments: 23 pages and 22 figures. Accepted for publication in MNRAS. At time of submission the electronic tables are only available from https:// doi.org/10.24378/exe.2124

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

We present an $i$-band photometric study of over 800 young stellar objects in the OB association Cep OB3b, which samples timescales from 1 minute to ten years. Using structure functions we show that on all timescales ($\tau$) there is a monotonic decrease in variability from Class I to Class II through the transition disc (TD) systems to Class III, i.e. the more evolved systems are less variable. The Class Is show an approximately power-law increase ($\tau^{0.8}$) in variability from timescales of a few minutes to ten years. The Class II, TDs and Class III systems show a qualitatively different behaviour with most showing a power-law increase in variability up to a timescale corresponding to the rotational period of the star, with little additional variability beyond that timescale. However, about a third of the Class IIs show lower overall variability, but their variability is still increasing at 10 years. This behaviour can be explained if all Class IIs have two primary components to their variability. The first is an underlying roughly power-law variability spectrum, which evidence from the infrared suggests is driven by accretion rate changes. The second component is approximately sinusoidal and results from the rotation of the star. We suggest that the systems with dominant longer-timescale variability have a smaller rotational modulation either because they are seen at low inclinations or have more complex magnetic field geometries.
We derive a new way of calculating structure functions for large simulated datasets (the "fast structure function"), based on fast Fourier transforms.

[7]  arXiv:1912.01616 [pdf, other]

Title: The intracluster light and its role in galaxy evolution in clusters

Authors: Mireia Montes

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

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

The diffuse light in clusters of galaxies, or intracluster light, has attracted a lot of attention lately due to its potential in describing the assembly history of galaxy clusters and to explain the observed growth of the brightest cluster galaxy with time. The properties of this light (color, stellar populations, extent) give clues about its formation and, consequently, the processes that shape the cluster. Here, I will present a review on intracluster light, its history, properties and the particular observational problems and limitations associated with the study of this diffuse component in integrated light.

[8]  arXiv:1912.01619 [pdf, other]

Title: X-shooter Spectroscopy and HST Imaging of 15 Ultra Massive Quiescent Galaxies at $z\gtrsim2$

Authors: Mikkel Stockmann, Sune Toft, Anna Gallazzi, Stefano Zibetti, Christopher J. Conselice, Berta Margalef-Bentabol, Johannes Zabl, Inger Jørgensen, Georgios E. Magdis, Carlos Gómez-Guijarro, Francesco M. Valentino, Gabriel B. Brammer, Daniel Ceverino, Isabella Cortzen, Iary Davidzon, Richardo Demarco, Andreas Faisst, Michaela Hirschmann, Jens-Kristian Krogager, Claudia D. Lagos, Allison W. S. Man, Carl J. Mundy, Yingjie Peng, Jonatan Selsing, Charles L. Steinhardt, Kathrine E. Whitaker

Comments: 30 pages, 10 figures, accepted in ApJ

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

We present a detailed analysis of a large sample of spectroscopically confirmed ultra-massive quiescent galaxies (${\rm{log}}(M_{\ast}/M_{\odot})\sim11.5$) at $z\gtrsim2$. This sample comprises 15 galaxies selected in the COSMOS and UDS fields by their bright K-band magnitudes and followed up with VLT/X-shooter spectroscopy and HST/WFC3 $H_{F160W}$ imaging. These observations allow us to unambiguously confirm their redshifts ascertain their quiescent nature and stellar ages, and to reliably assess their internal kinematics and effective radii. We find that these galaxies are compact, consistent with the high mass end of the mass-size relation for quiescent galaxies at $z=2$. Moreover, the distribution of the measured stellar velocity dispersions of the sample is consistent with the most massive local early-type galaxies from the MASSIVE Survey showing that evolution in these galaxies, is dominated by changes in size. The HST images reveal, as surprisingly high, that $40\ \%$ of the sample have tidal features suggestive of mergers and companions in close proximity, including three galaxies experiencing ongoing major mergers. The absence of velocity dispersion evolution from $z=2$ to $0$, coupled with a doubling of the stellar mass, with a factor of four size increase and the observed disturbed stellar morphologies support dry minor mergers as the primary drivers of the evolution of the massive quiescent galaxies over the last 10 billion years.

[9]  arXiv:1912.01620 [pdf, other]

Title: Submillimetre Transient Science in the Next Decade: EAO Submillimetre Futures White Paper Series, 2019

Authors: Steve Mairs, Gregory Herczeg, Doug Johnstone, Jeong-Eun Lee, Simon Coude, Alexandra J. Tetarenko, Jenny Hatchell, Aleks Scholz, Bhavana Lalchand, Wen-Ping Chen, Carlos Contreras Pena, Tim Naylor, Kevin Lacaille, Peter Scicluna

Comments: 11 pages, 4 figures; Part of the 2019 EAO Submillimetre Futures Paper Series

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

This white paper gives a brief summary of the time domain science that has been performed with the JCMT in recent years and highlights the opportunities for continuing work in this field over the next decade. The main focus of this document is the JCMT Transient Survey, a large program initiated in 2015 to measure the frequency and amplitude of variability events associated with protostars in nearby star-forming regions. After summarising the major accomplishments so far, an outline is given for extensions to the current survey, featuring a discussion on what will be possible with the new 850 micron camera that is expected to be installed in late 2022. We also discuss possible applications of submillimetre monitoring to active galactic nuclei, X-ray binaries, asymptotic giant branch stars, and flare stars.

[10]  arXiv:1912.01621 [pdf, other]

Title: The ALPINE-ALMA [CII] Survey: Multi-Wavelength Ancillary Data and Basic Physical Measurements

Authors: A. L. Faisst, D. Schaerer, B. C. Lemaux, P. A. Oesch, Y. Fudamoto, P. Cassata, M. Bethermin, P. L. Capak, O. Le Fevre, J. D. Silverman, L. Yan, M. Ginolfi, A. M. Koekemoer, L. Morselli, R. Amorin, S. Bardelli, M. Boquien, G. Brammer, A. Cimatti, M. Dessauges-Zavadsky, S. Fujimoto, C. Gruppioni, N. P. Hathi, S. Hemmati, G. C. Jones, Y. Khusanova, F. Loiacono, F. Pozzi, M. Talia, L. A. M. Tasca, D. A. Riechers, G. Rodighiero, M. Romano, N. Scoville, S. Toft, L. Vallini, D. Vergani, G. Zamorani, E. Zucca

Comments: 53 pages, 33 figures, 7 tables (including Appendix), submitted to ApJS

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

We present the ancillary data and basic physical measurements for the galaxies in the ALMA Large Program to Investigate C+ at Early Times (ALPINE) survey - the first large multi-wavelength survey which aims at characterizing the gas and dust properties of 118 main-sequence galaxies at redshifts 4.4 < z < 5.9 via the measurement of [CII] emission at 158 micro-meter and the surrounding far-infrared (FIR) continuum in conjunction with a wealth of optical and near-infrared data. We outline in detail the spectroscopic data and selection of the galaxies as well as the ground- and space-based imaging products. In addition, we provide several basic measurements including stellar masses, star formation rates (SFR), rest-frame ultra-violet (UV) luminosities, UV continuum slopes ($\beta$), and absorption line redshifts, as well as H-alpha emission derived from Spitzer colors. Overall, we find that the ALPINE sample is representative of the 4 < z < 6 galaxy population and only slightly biased towards bluer colors ($\Delta\beta$ ~ 0.2). Using [CII] as tracer of the systemic redshift (confirmed for one galaxy at z=4.5 for which we obtained optical [OII]3727um emission), we confirm red shifted Ly-alpha emission and blue shifted absorption lines similar to findings at lower redshifts. By stacking the rest-frame UV spectra in the [CII] rest-frame we find that the absorption lines in galaxies with high specific SFR are more blue shifted, which could be indicative of stronger winds and outflows.

[11]  arXiv:1912.01622 [pdf, other]

Title: Testing gamma-ray models of blazars in the extragalactic sky

Authors: Silvia Manconi, Michael Korsmeier, Fiorenza Donato, Nicolao Fornengo, Marco Regis, Hannes Zechlin

Comments: 13 pages, 7 figures

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

The global contribution of unresolved gamma-ray point sources to the extragalactic gamma-ray background has been recently measured down to gamma-ray fluxes lower than those reached with standard source detection techniques, and by employing the statistical properties of the observed gamma-ray counts. We investigate and exploit the complementarity of the information brought by the one-point statistics of photon counts (using more than 10 years of Fermi-LAT data) and by the recent measurement of the angular power spectrum of the unresolved gamma-ray background (based on 8 years of Fermi-LAT data). We determine, under the assumption that the source-count distribution of the brightest unresolved objects is dominated by blazars, their gamma-ray luminosity function and spectral energy distribution down to fluxes almost two orders of magnitude smaller than the threshold for detecting resolved sources. The different approaches provide consistent predictions for the gamma-ray luminosity function of blazars, and they show a significant complementarity.

[12]  arXiv:1912.01625 [pdf, ps, other]

Title: Discovery of Protoclusters at z~3.7 & 4.9: Embedded in Primordial Superclusters

Authors: Jun Toshikawa, Matthew A. Malkan, Nobunari Kashikawa, Roderik Overzier, Hisakazu Uchiyama, Kazuaki Ota, Shogo Ishikawa, Kei Ito

Comments: Accepted for publication in ApJ, 24 pages, 12 figures, 5 tables

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

We have carried out follow-up spectroscopy on three overdense regions of $g$- and $r$-dropout galaxies in the Canada-France-Hawaii Telescope Legacy Survey Deep Fields, finding two new protoclusters at $z=4.898$, 3.721 and a possible protocluster at $z=3.834$. The $z=3.721$ protocluster overlaps with a previously identified protocluster at $z=3.675$. The redshift separation between these two protoclusters is $\Delta z=0.05$, which is slightly larger than the size of typical protoclusters. Therefore, if they are not the progenitors of a $>10^{15}\,\mathrm{M_\odot}$ halo, they would grow into closely-located independent halos like a supercluster. The other protocluster at $z=4.898$ is also surrounded by smaller galaxy groups. These systems including protoclusters and neighboring groups are regarded as the early phase of superclusters. We quantify the spatial distribution of member galaxies of the protoclusters at $z=3.675$ and 3.721 by fitting triaxial ellipsoids, finding a tentative difference: one has a pancake-like shape while the other is filamentary. This could indicate that these two protoclusters are in different stages of formation. We investigate the relation between redshift and the velocity dispersion of protoclusters, including other protoclusters from the literature, in order to compare their dynamical states. Although there is no significant systematic trend in the velocity dispersions of protoclusters with redshift, the distribution is skewed to higher velocity dispersion over the redshift range of $z=2\mathrm{-}6$. This could be interpreted as two phases of cluster formation, one dominated by the steady accretion of galaxies, and the other by the merging between group-size halos, perhaps depending on the surrounding large-scale environments.

[13]  arXiv:1912.01626 [pdf, other]

Title: The rest-frame UV luminosity function at $z \simeq 4$: a significant contribution of AGN to the bright-end of the galaxy population

Authors: N. J. Adams, R. A. A. Bowler, M. J. Jarvis, B. Häußler, R. J. McLure, A. Bunker, J. S. Dunlop, A. Verma

Comments: 14 pages, 9 figures, 3 tables, Submitted to MNRAS

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

We measure the rest-frame UV luminosity function (LF) at $z \sim 4$ self-consistently over a wide range in absolute magnitude ($-27 \lesssim M_{\rm UV} \lesssim -20$). The LF is measured with 46,904 sources selected using a photometric redshift approach over $ \sim 6$ deg$^2$ of the combined COSMOS and XMM-LSS fields. We simultaneously fit for both AGN and galaxy LFs using a combination of Schechter or Double Power Law (DPL) functions alongside a single power law for the faint-end slope of the AGN LF. We find a lack of evolution in the shape of the bright-end of the LBG component when compared to other studies at $z \simeq 5$ and evolutionary recipes for the UV LF. Regardless of whether the LBG LF is fit with a Schechter function or DPL, AGN are found to dominate at $M_{\rm UV} < -23.5$. We measure a steep faint-end slope of the AGN LF with $\alpha_{AGN} = -2.09^{+0.35}_{-0.38}$ ($-1.66^{+0.29}_{-0.58}$) when fit alongside a Schechter function (DPL) for the galaxies. Our results suggest that if AGN are morphologically selected it results in a bias to lower number densities. Only by considering the full galaxy population over the transition region from AGN to LBG domination can an accurate measurement of the total LF be attained.

[14]  arXiv:1912.01627 [pdf, other]

Title: The binary content of multiple populations in NGC 3201

Authors: Sebastian Kamann, Benjamin Giesers, Nate Bastian, Jarle Brinchmann, Stefan Dreizler, Fabian Göttgens, Tim-Oliver Husser, Marilyn Latour, Peter M. Weilbacher, Lutz Wisotzki

Comments: Resubmitted to A&A after favourable referee report. 4 pages, 2 figures

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

We investigate the binary content of the two stellar populations that coexist in the globular cluster NGC 3201. Previous studies of binary stars in globular clusters have reported higher binary fractions in their first populations (P1, having field-like abundances) compared to their second populations (P2, having anomalous abundances). This is interpreted as evidence for the latter forming more centrally concentrated. In contrast to previous studies, our analysis focuses on the cluster centre, where comparable binary fractions between the populations are predicted because of the short relaxation times. However, we find that even in the centre of NGC 3201, the observed binary fraction of P1 is higher, (23.1 +/- 6.2)% compared to (8.2 +/- 3.5)% in P2. Our results are difficult to reconcile with a scenario where the populations only differ in their initial concentrations, but instead suggests that the populations also formed with different fractions of binary stars.

[15]  arXiv:1912.01632 [pdf, other]

Title: Global 3-D Radiation Magnetohydrodynamic Simulations for FU Ori's Accretion Disk and Observational Signatures of Magnetic Fields

Authors: Zhaohuan Zhu, Yan-Fei Jiang, James M. Stone

Comments: 21 pages, 18 figures, submitted to MNRAS

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

FU Orionis systems are outbursting protoplanetary disks where the accretion disks outshine the central stars and strong disk winds are launched. Magnetic fields in these accretion disks have previously been detected through their Zeeman effects in spectropolarimetry observations. We carry out global radiation ideal MHD simulations to study FU Ori's inner accretion disk. We find that (1) when the disk is threaded by vertical magnetic fields, most accretion occurs in the magnetically dominated atmosphere at z$\sim$R, similar to the "surface accretion" mechanism in previous locally-isothermal MHD simulations. (2) A moderate disk wind is launched in these vertical field simulations with terminal speeds of $\sim$300-500 km/s and a mass loss rate of 1-10\% disk accretion rate. Both the speed and loss rate are consistent with observations. Disk wind fails to be launched in net toroidal field simulations. (3) The disk photosphere at the unit optical depth can be either in the wind launching region or the accreting surface region, depending on the accretion rates and the disk radii. Magnetic fields have drastically different directions and magnitudes between these two regions. Our fiducial model agrees with previous optical Zeeman observations regarding both the field directions and magnitudes. On the other hand, simulations indicate that future Zeeman observations at near-IR wavelengths or towards other FU Orionis systems may reveal very different magnetic field structures. (4) Due to energy loss by the disk wind, the disk photosphere temperature is lower than that predicted by the thin disk theory, and the previously inferred disk accretion rate may be lower than the real accretion rate by a factor of $\sim$2-3.

[16]  arXiv:1912.01634 [pdf, other]

Title: Stellar Profile Independent Determination of the Dark Matter Distribution of the Fornax Local Group Dwarf Spheroidal Galaxy

Authors: Sasha Brownsberger, Lisa Randall

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

The local group dwarf spheroidal galaxies (LG dSphs) are among the most promising astrophysical targets for probing the small scale structure of dark matter (DM) subhalos. We describe a method for testing the correspondence between proposed DM halo models and observations of stellar populations within LG dSphs. By leveraging the gravitational potential of any proposed DM model and the available stellar kinematical data, we can derive a prediction for the observed stellar surface density of an LG dSph that can be directly compared with observations. Because we do not make any reference to an assumed surface brightness profile, our model can be applied to exotic DM distributions that produce atypical stellar density distributions. We use our methodology to determine that the DM halo of the Fornax LG dSph is more likely cored than cusped, ascertain that it is characterized by a semi-minor to semi-major axis ratio in minor tension with simulations, and find no substantial evidence of a disk within the dSph's larger DM halo.

[17]  arXiv:1912.01637 [pdf]

Title: Collisional disruption of highly porous targets in the strength regime: Effects of mixture

Authors: Yuichi Murakami, Akiko M. Nakamura, Koki Yokoyama, Yusuke Seto, Sunao Hasegawa

Comments: Planetary and Space Science, accepted

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

Highly porous small bodies are thought to have been ubiquitous in the early solar system. Therefore, it is essential to understand the collision process of highly porous objects when considering the collisional evolution of primitive small bodies in the solar system. To date, impact disruption experiments have been conducted using high-porosity targets made of ice, pumice, and glass, and numerical simulations of impact fracture of porous bodies have also been conducted. However, a variety of internal structures of high-porosity bodies are possible. Therefore,laboratory experiments and numerical simulations in the wide parameter space are necessary.
In this study, high-porosity targets of sintered hollow glass beads and targets made by mixing perlite with hollow beads were used in a collision disruption experiment to investigate the effects of the mixture on collisional destruction of high-porosity bodies. Among the targets prepared under the same sintering conditions, it was found that the targets with more impurities tend to have lower compressive strength and lower resistance against impact disruption. Further, destruction of the mixture targets required more impact energy density than would have been expected from compressive strength. It is likely that the perlite grains in the target matrix inhibit crack growth through the glass framework. The mass fraction of the largest fragment collapsed to a single function of a scaling parameter of energy density in the strength regime ({\Pi}_s) when assuming ratios of tensile strength to compressive strength based on a relationship obtained for ice-silicate mixtures.

[18]  arXiv:1912.01638 [pdf, other]

Title: Detuning primordial black hole dark matter with early matter domination and axion monodromy

Authors: Guillermo Ballesteros, Julián Rey, Fabrizio Rompineve

Comments: 28 pages

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

We present a scenario that ameliorates the tuning problems present in models of primordial black hole dark matter from inflation. Our setup employs the advantages of gravitational collapse in a long epoch of early matter domination with reheating temperature $\lesssim 10^{6}~\text{GeV}$. Furthermore, we make use of a string-inspired class of models where the inflaton is identified with a non-compact axion field. In this framework, the presence of multiple local minima in the inflaton potential can be traced back to an approximate discrete shift symmetry. This scenario allows the formation of primordial black holes in the observationally viable range of masses ($M_{\text{PBH}}\sim 10^{-13}M_{\odot}-10^{-16}M_{\odot}$) accounting for all dark matter, and in excellent agreement with the CMB. Crucially, we find a significant reduction in the required tuning of the parameters of the inflationary potential, in contrast to the standard case of primordial black hole formation during radiation domination.

[19]  arXiv:1912.01647 [pdf, other]

Title: Bipolar Planetary Nebulae from Outflow Collimation by Common Envelope Evolution

Authors: Yangyuxin Zou, Adam Frank, Zhuo Chen, Thomas Reichardt, Orsola De Marco, Eric G. Blackman, Jason Nordhaus, Bruce Balick, Jonathan Carroll-Nellenback, Luke Chamandy, Baowei Liu

Comments: 15 pages, 13 figures

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

The morphology of bipolar planetary nebulae can be attributed to interactions between a fast wind from the central engine and dense toroidal shaped ejecta left over from common envelope evolution. Here we use the 3-D hydrodynamic adaptive mesh refinement code AsrtroBEAR to study the possibility that bipolar preplanetary nebula outflows can emerge collimated even from an uncollimated spherical wind in the aftermath of a common envelope event. The output of a single common envelope simulation via the smoothed particle hydrodynamics code PHANTOM serves as the initial conditions for our simulations. Four cases of winds, all with high enough momenta to account for observed high momenta preplanetary nebula outflows, are injected spherically from the region of the common envelope binary remnant into the ejecta. We compare cases with two different values of momenta and cases with no radiative cooling versus application of optically thin emission via a cooling curve to the outflow. Our simulations show that in all cases highly collimated bipolar outflows result from deflection of the spherical wind via the interaction with the common envelope ejecta. Significant asymmetries between the top and bottom lobes are seen in all cases, reflecting the influence of asymmetries in the turbulent dynamics of the common envelope interaction. The asymmetry is strongest for the lower momentum case with radiative cooling. While real post common envelope winds may not be spherical, our models show that collimation via "inertial confinement" will be strong enough to create jet-like outflows even beginning with maximally uncollimated drivers.

[20]  arXiv:1912.01653 [pdf, other]

Title: Primordial black holes and gravitational waves in non-standard cosmologies

Authors: Sukannya Bhattacharya, Subhendra Mohanty, Priyank Parashari

Comments: 22 pages, 6 figures

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

For primordial black holes (PBH) to form a considerable fraction of cold dark matter, the required amplitude of primordial scalar perturbations is quite large ($P_{\zeta}(k) \sim 10^{-2}$) if PBH is formed in radiation epoch. In alternate cosmological histories, where additional epochs of arbitrary equation of state precede radiation epoch, the dynamics of PBH formation and relevant mass ranges can be different leading to requirement of lower primordial power at smaller scales of inflation. Moreover, this alternate history can modify the predictions for the gravitational wave (GW) spectrum, which can be probed by upcoming GW observations. In this paper we show that an early kination epoch can lead to percent level abundance of PBH for a lower amplitude of $P_{\zeta}(k)$ as compared to PBH formation in a standard radiation epoch. Moreover, we calculate the effect of early kination epoch on the GW spectrum for first and second orders in perturbation which show enhancement in the amplitude of the GW spectrum in a kination epoch with respect to that in a standard radiation epoch.

[21]  arXiv:1912.01660 [pdf, other]

Title: The [α/Fe]-[Fe/H] relation in the E-MOSAICS simulations: its connection to the birth place of globular clusters and the fraction of globular cluster field stars in the bulge

Authors: Meghan E. Hughes, Joel L.Pfeffer, Marie Martin, Marta Reina-Campos, Nate Bastian, Robert A. Crain, J. M. Diederik Kruijssen

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

The {\alpha}-element abundances of the globular cluster (GC) and field star populations of galaxies encode information about the formation of each of these components. We use the E-MOSAICS cosmological simulations of ~L* galaxies and their GCs to investigate the [{\alpha}/Fe]-[Fe/H] distribution of field stars and GCs in 25 Milky Way-mass galaxies. The [{\alpha}/Fe]-[Fe/H] distribution go GCs largely follows that of the field stars and can also therefore be used as tracers of the [{\alpha}/Fe]-[Fe/H] evolution of the galaxy. Due to the difference in their star formation histories, GCs associated with stellar streams (i.e. which have recently been accreted) have systematically lower [{\alpha}/Fe] at fixed [Fe/H]. Therefore, if a GC is observed to have low [{\alpha}/Fe] for its [Fe/H] there is an increased probability that this GC was accreted recently alongside a dwarf galaxy. There is a wide range of shapes for the field star [{\alpha}/Fe]-[Fe/H] distribution, with a notable subset of galaxies exhibiting bimodal distributions, in which the high [{\alpha}/Fe] sequence is mostly comprised of stars in the bulge, a high fraction of which are from disrupted GCs. We calculate the contribution of disrupted GCs to the bulge component of the 25 simulated galaxies and find values between 0.3-14 per cent, where this fraction correlates with the galaxy's formation time. The upper range of these fractions is compatible with observationally-inferred measurements for the Milky Way, suggesting that in this respect the Milky Way is not typical of L* galaxies, having experienced a phase of unusually rapid growth at early times.

[22]  arXiv:1912.01671 [pdf, ps, other]

Title: The Solar Radius at 37 GHz through Cycles 22 to 24

Authors: Caius L. Selhorst, Juha Kallunki, C. G. Giménez de Castro, Adriana Valio, Joaquim E. R. Costa

Comments: 11 pages, 5 figures, accepted for publication in Solar Physics

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

To better understand the influence of the activity cycle on the solar atmosphere, we report the time variation of the radius observed at 37 GHz ($\lambda$=8.1 mm) obtained by the Mets\"ahovi Radio Observatory (MRO) through Solar Cycles 22 to 24 (1989-2015). Almost 5800 maps were analyzed, however, due to instrumental setups changes the data set showed four distinct behaviors, which requested a normalisation process to allow the whole interval analysis. When the whole period was considered, the results showed a positive correlation index of 0.17 between the monthly means of the solar radius at 37 GHz and solar flux obtained at 10.7 cm (F10.7). This correlation index increased to 0.44, when only the data obtained during the last period without instrumental changes were considered (1999-2015). The solar radius correlation with the solar cycle agrees with the previous results obtained at mm/cm wavelengths (17 and 48 GHz), nevertheless, this result is the opposite of that reported at submillimetre wavelengths (212 and 405 GHz).

[23]  arXiv:1912.01675 [pdf, other]

Title: Recent Progress on the GAPS Time of Flight System

Authors: S. Quinn

Comments: 36th International Cosmic Ray Conference (ICRC 2019). 7 pages, 7 figures

Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); High Energy Astrophysical Phenomena (astro-ph.HE); Instrumentation and Detectors (physics.ins-det)

The General AntiParticle Spectrometer (GAPS) is a balloon-borne cosmic-ray antimatter experiment that uses the exotic atom technique, eliminating the requirement for strong B-fields used by conventional magnetic spectrometers. It will be sensitive to antideuterons with kinetic energies of 0.05-0.25 GeV / nucleon, which are highly motivated candidates for indirect dark matter detection. Moreover, GAPS will provide new information on the antiproton spectrum from $0.07<T<0.25$ GeV. The GAPS design is based on a lithium drifted silicon tracker and plastic scintillator time of flight (TOF) system. The latter is the focus of this contribution.
Currently, the TOF system includes an outer "umbrella" consisting of 132 counters covering an area of 38 m$^2$ and a nearly hermetic inner "cube" with 64 counters and area of 15 m$^2$. The counters will be mechanically secured to the gondola using an innovative carbon fiber structure. Each end of the 196 counters will be read out using a silicon photomultiplier (SiPM) based analog front end with a high gain timing channel and low gain trigger channel. The high gain channel is sampled and digitized with a custom readout board that uses the DRS-4 ASIC. A local trigger monitors multiple programmable threshold levels for all 392 counter ends. A master trigger analyzes the local trigger hit patterns and initiates a TOF read out for an interesting event. A central computer then analyzes and estimates key observables. This contribution summarizes the design, performance, and prototype development of the TOF system and the path going forward in 2019 and 2020 towards construction and integration of the system.

[24]  arXiv:1912.01681 [pdf, other]

Title: Disk Instabilities Caused the 2018 Outburst of AG Draconis

Authors: Helena M. Richie, W. M. Wood-Vasey, Lou Coban

Comments: 9 pages, 4 figures

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

Symbiotic binary AG Draconis (AG Dra) has an well-established outburst behavior based on an extensive observational history. Usually, the system undergoes a 9-15 yr period of quiescence with a constant average energy emitted, during which the system's orbital period of $\sim$550 d can be seen at shorter wavelengths (particularly in the U-band) as well as a shorter period of $\sim$355 d thought to be due to pulsations of the cool component. After a quiescent period, the marker of an active period is usually a major (cool) outburst of up to $\textrm{V}=8.4$ mag, followed by a series of minor (hot) outbursts repeating at a period of approximately 1 y. However, in 2016 April after a 9-year period of quiescence AG Dra exhibited unusual behavior: it began an active phase with a minor outburst followed by two more minor outbursts repeating at an interval of $\sim$1 y. We present R-band observations of AG Dra's 2018 April minor outburst and an analysis of the outburst mechanism and reports on the system's activity levels following the time of its next expected outburst. By considering the brightening and cooling times, the scale of the outburst, and its temperature evolution we have determined that this outburst was of dwarf nova nature.

[25]  arXiv:1912.01699 [pdf, ps, other]

Title: Impact of Binary Stars on Planet Statistics -- I. Planet Occurrence Rates, Trends with Stellar Mass, and Wide Companions to Hot Jupiter Hosts

Authors: Maxwell Moe, Kaitlin M. Kratter

Comments: 24 pages, 11 figures, submitted to MNRAS

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

Close binaries suppress the formation of circumstellar (S-type) planets and therefore significantly bias the inferred planet occurrence rates and statistical trends. After compiling various radial velocity and high-resolution imaging surveys, we determine that binaries with a < 1 au fully suppress S-type planets, binaries with a = 10 au host close planets at 15% the occurrence rate of single stars, and wide binaries with a > 200 au have a negligible effect on planet formation. We show that F = 43% +/- 6% of solar-type primaries do not host close planets due to suppression by close stellar companions. By removing spectroscopic binaries from their samples, radial velocity surveys for giant planets boost their detection rates by a factor of 1/(1-F) = 1.8 +/- 0.2 compared to transiting surveys. This selection bias fully accounts for the discrepancy in hot Jupiter occurrence rates inferred from these two detection methods. Correcting for both planet suppression by close binaries and transit dilution by wide binaries, the occurrence rate of small planets orbiting single G-dwarfs is 2.1 +/- 0.3 times larger than the rate inferred from all G-dwarfs in the Kepler survey. About half (but not all) of the observed increase in small, short-period planets toward low-mass hosts can be explained by the corresponding decrease in the binary fraction. Finally, we demonstrate that the apparent enhancement of wide stellar companions to hot Jupiter hosts is due to multiple selection effects. Although very close binaries with secondary masses M_2 > 10 M_J preferentially have wide tertiary companions, genuine hot Jupiters with M_p = 0.2-4 M_J that formed via core accretion do not exhibit a statistically significant excess of wide stellar companions.

[26]  arXiv:1912.01714 [pdf, other]

Title: Laboratory Experiments on the Motion of Dense Dust Clouds

Authors: Niclas Schneider, Gerhard Wurm

Journal-ref: The Astrophysical Journal Letters, Volume 886, Number 2, 2019

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

In laboratory experiments, we study the motion of levitated, sedimenting clouds of sub-mm grains at low ambient pressure and at high solid-to-gas ratios $\epsilon$. The experiments show a collective behavior of particles, i.e. grains in clouds settle faster than an isolated grain. In collective particle clouds, the sedimentation velocity linearly depends on $\epsilon$ and linearly depends on the particle closeness $C$. However, collective behavior only sets in at a critical value $\epsilon_{\rm crit}$ which linearly increases with the experiment Stokes number St. For $\rm St <0.003 $ particles always behave collectively. For large Stokes numbers, large solid-to-gas ratios are needed to trigger collective behavior, e.g. $\epsilon_{\rm crit} = 0.04$ at $\rm St = 0.01$. Applied to protoplanetary disks, particles in dense environments will settle faster. In balance with upward gas motions (turbulent diffusion, convection) the thickness of the midplane particle layer will be smaller than calculated based on individual grains, especially for dust. For pebbles, large solid-to-gas ratios are needed to trigger instabilities based on back-reaction.

[27]  arXiv:1912.01737 [pdf, other]

Title: Formation of SMBH seeds in Pop III star clusters through collisions : the importance of mass loss

Authors: P.J. Alister Seguel, D.R.G. Schleicher, T.C.N. Boekholt, M. Fellhauer, R.S. Klessen

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

Runaway collisions in dense clusters may lead to the formation of supermassive black hole (SMBH) seeds, and this process can be further enhanced by accretion, as recent models of SMBH seed formation in Pop. III star clusters have shown. This may explain the presence of supermassive black holes already at high redshift, z>6. However, in this context, mass loss during collisions was not considered and could play an important role for the formation of the SMBH seed. Here, we study the effect of the mass loss, due to collisions of the protostars, in the formation and evolution of a massive object in a dense primordial cluster. We consider both constant mass loss fractions as well as analytic models based on the stellar structure of the collision components. Our calculations indicate that mass loss can significantly affect the final mass of the possible SMBH seed. Considering a mass loss of 5% for every collision, we can lose between 60-80% of the total mass obtained when mass loss is not considered, while for the analytical models the mass of the final object is reduced by 15-40%, depending on the accretion model for the cluster we study. Altogether, we obtain masses of the order of $10^4M_{\odot}$, which are still massive enough to be SMBH seeds.

[28]  arXiv:1912.01743 [pdf, other]

Title: Apparent superluminal core expansion and limb brightening in the candidate neutrino blazar TXS 0506+056

Authors: E. Ros (MPIfR Bonn), M. Kadler (U. Würzburg), M. Perucho (U. València), B. Boccardi (MPIfR Bonn), H.-M. Cao (IRA-INAF Bologna), M. Giroletti (IRA-INAF Bologna), F. Krauß (Penn State Univ.), R. Ojha (NASA/GSFC, U. Maryland, Catholic U. America)

Comments: Accepted for publication in Astronomy & Astronomy Letters; 5 pages, 3 figures, 2 tables

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

IceCube has reported a very-high-energy neutrino (IceCube-170922A) in a region containing the blazar TXS 0506+056. Correlated {\gamma}-ray activity has led to the first high-probability association of a high-energy neutrino with an extragalactic source. This blazar has been found to be in a radio outburst during the neutrino event. We have performed target-of-opportunity VLBI imaging observations at 43 GHz frequency with the VLBA two and eight months, respectively, after the neutrino event. We produced two images of TXS 0506+056 with angular resolutions of (0.2x1.1) mas and (0.2x0.5) mas, respectively. The source shows a compact, high brightness temperature core (albeit not approaching the equipartition limit, Readhead 1994) and a bright and originally very collimated inner jet. Beyond about 0.5 mas from the mm-VLBI core, the jet loses this tight collimation and expands rapidly. During the months after the neutrino event associated with this source, the overall flux density is rising. This flux density increase happens solely within the core. The core expands in size with apparent superluminal velocity during these six months so that the brightness temperature drops by a factor of three in spite of the strong flux density increase. The radio jet of TXS 0506+056 shows strong signs of deceleration and/or a spine-sheath structure within the inner 1 mas (corresponding to about 70 pc to 140 pc in deprojected distance) from the mm-VLBI core. This structure is consistent with theoretical models that attribute the neutrino and {\gamma}-ray production to interactions of electrons and protons in the highly-relativistic jet spine with external photons originating from a slower-moving jet region. Proton loading due to jet-star interactions in the inner host galaxy is suggested as the possible cause of deceleration

[29]  arXiv:1912.01747 [pdf, other]

Title: Radio Burst and Circular Polarization Studies of the Solar Corona at Low Frequencies

Authors: Patrick I. McCauley

Comments: PhD thesis

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

Low-frequency (80-240 MHz) radio observations of the solar corona are presented using the Murchison Widefield Array (MWA), and several discoveries are reported. The corona is reviewed, followed by chapters on Type III bursts and circularly-polarized quiescent emission. The second chapter details new Type III burst dynamics. One source component at higher frequencies splits into two at lower frequencies, where the two components rapidly diverge. This is attributed to electron beams traversing a divergent magnetic field configuration, which is supported by extreme ultraviolet jet observations outlining a coronal null point. The third chapter uses Type III burst heights as density probes. Harmonic plasma emission implies ~4x enhancements over background models. This can be explained by electron beams traveling along dense fibers or by propagation effects that elevate apparent source heights. The quiescent corona is compared to model predictions to conclude that propagation effects can largely but not entirely explain the apparent density enhancements. The fourth chapter surveys over 100 spectropolarimetric observing runs. Around 700 compact sources are detected with polarization fractions from less than 0.5% to nearly 100%. They are interpreted as plasma emission noise storm sources down to levels not previously observable. A "bullseye" structure is reported for coronal holes, where an outer ring surrounds an oppositely-polarized central component that does not match the sign expected of thermal bremsstrahlung. The large-scale polarization structure is shown to be well-correlated with that of a global magnetic field model. The last chapter summarizes results and outlines future work. A preliminary comparison of polarization images to model predictions is shared, along with coronal mass ejection observations revealing a radio arc that is morphologically similar to the white-light structure.

[30]  arXiv:1912.01770 [pdf, other]

Title: Electrostatic turbulence and Debye-scale structures in collisionless shocks

Authors: R. Wang, I.Y. Vasko, F.S. Mozer, S.D. Bale, A.V. Artemyev, J.W. Bonnell, R. Ergun, B. Giles, P.-A. Lindqvist, C.T. Russell, R. Strangeway

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

We present analysis of more than one hundred large-amplitude bipolar electrostatic structures in a quasi-perpendicular supercritical Earth's bow shock crossing, measured by the Magnetospheric Multiscale spacecraft. The occurrence of the bipolar structures is shown to be tightly correlated with magnetic field gradients in the shock transition region. The bipolar structures have negative electrostatic potentials and spatial scales of a few Debye lengths. The bipolar structures propagate highly oblique to the shock normal with velocities (in the plasma rest frame) of the order of the ion-acoustic velocity. We argue that the bipolar structures are ion phase space holes produced by the two-stream instability between incoming and reflected ions. This is the first identification of the ion two-stream instability in collisionless shocks. The implications for electron acceleration are discussed.

[31]  arXiv:1912.01771 [pdf, other]

Title: Radio Observations of Supernova Remnant G1.9+0.3

Authors: Kieran J. Luken, Miroslav D. Filipović, Nigel I. Maxted, Roland Kothes, Ray P. Norris, James R. Allison, Rebecca Blackwell, Catherine Braiding, Robert Brose, Michael Burton, Ain Y. De Horta, Tim J. Galvin, Lisa Harvey-Smith, Natasha Hurley-Walker, Denis Leahy, Nicholas O. Ralph, Quentin Roper, Gavin Rowell, Iurii Sushch, Dejan Urošević, Graeme F. Wong

Comments: 17 Pages, 13 Figures

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

We present 1 to 10GHz radio continuum flux density, spectral index, polarisation and Rotation Measure (RM) images of the youngest known Galactic Supernova Remnant (SNR) G1.9+0.3, using observations from the Australia Telescope Compact Array (ATCA). We have conducted an expansion study spanning 8 epochs between 1984 and 2017, yielding results consistent with previous expansion studies of G1.9+0.3. We find a mean radio continuum expansion rate of ($0.78 \pm 0.09$) per cent year$^{-1}$ (or $\sim8900$ km s$^{-1}$ at an assumed distance of 8.5 kpc), although the expansion rate varies across the SNR perimeter. In the case of the most recent epoch between 2016 and 2017, we observe faster-than-expected expansion of the northern region. We find a global spectral index for G1.9+0.3 of $-0.81\pm0.02$ (76 MHz$-$10 GHz). Towards the northern region, however, the radio spectrum is observed to steepen significantly ($\sim -$1). Towards the two so called (east & west) "ears" of G1.9+0.3, we find very different RM values of 400-600 rad m$^{2}$ and 100-200 rad m$^{2}$ respectively. The fractional polarisation of the radio continuum emission reaches (19 $\pm$ 2)~per~cent, consistent with other, slightly older, SNRs such as Cas~A.

[32]  arXiv:1912.01813 [pdf, other]

Title: X-ray Spectra from Plasmas with High-Energy Electrons: kappa-distributions and e-e Bremsstrahlung

Authors: Xiaohong Cui, Adam R. Foster, Takayuki Yuasa, Randall K. Smith

Comments: 10 pages, 7 figures, ApJS in press

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

Shocks, turbulence and winds all influence the electron velocity distribution in hot plasmas, exciting lower-energy electrons and generating a high-energy (typically power-law) tail. This effect, typically described as a kappa distribution can affect both the line and continuum X-ray spectrum emitted by the plasma. Hahn & Savin (2015) proposed a "Maxwellian decomposition" to generate the rate coefficients of kappa distributions. Using their method and the AtomDB atomic database, we have developed a general model to calculate the emission from a plasma with a kappa distribution. We compare our kappa results for the charge state distribution and spectra of oxygen to those from KAPPA package with the ion data available within the CHIANTI atomic database. Sufficiently energetic electrons, created either in a kappa distribution or merely a very hot Maxwellian plasma, can also emit via electron-electron (e-e) bremsstrahlung, a process not previously included in AtomDB. We have added this process to AtomDB and apply it to calculate the temperature gradients, as well as the total spectra from the post-shock regions of an accreting magnetic cataclysmic variable (CV). We find the contribution of e-e bremsstrahlung to the total spectra exceeds 10% at KT\sim 100 keV, with the total emissivity in the post-shock accretion stream differing by more than 10% at energies above 60 keV.

[33]  arXiv:1912.01821 [pdf, other]

Title: Cool Jupiters greatly outnumber their toasty siblings: Occurrence rates from the Anglo-Australian Planet Search

Authors: Robert A. Wittenmyer, Songhu Wang, Jonathan Horner, R.P. Butler, C.G. Tinney, B.D. Carter, D.J. Wright, H.R.A. Jones, J. Bailey, S.J. O'Toole, Daniel Johns

Comments: Accepted for publication in MNRAS

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

Our understanding of planetary systems different to our own has grown dramatically in the past 30 years. However, our efforts to ascertain the degree to which the Solar system is abnormal or unique have been hindered by the observational biases inherent to the methods that have yielded the greatest exoplanet hauls. On the basis of such surveys, one might consider our planetary system highly unusual - but the reality is that we are only now beginning to uncover the true picture. In this work, we use the full eighteen-year archive of data from the Anglo-Australian Planet Search to examine the abundance of 'Cool Jupiters' - analogs to the Solar system's giant planets, Jupiter and Saturn. We find that such planets are intrinsically far more common through the cosmos than their siblings, the hot Jupiters. We find that the occurrence rate of such 'Cool Jupiters' is $6.73^{+2.09}_{-1.13}$\%, almost an order of magnitude higher than the occurrence of hot Jupiters (at $0.84^{+0.70}_{-0.20}$\%). We also find that the occurrence rate of giant planets is essentially constant beyond orbital distances of $\sim$1\,au. Our results reinforce the importance of legacy radial velocity surveys for the understanding of the Solar system's place in the cosmos.

[34]  arXiv:1912.01828 [pdf, other]

Title: Model-independent Estimations for the Cosmic Curvature from the Latest Strong Gravitational Lensing Systems

Authors: Huan Zhou, Zheng-Xiang Li

Comments: 8 pages, 7 figures, 2 tables, Accepted by ApJ

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

Model-independent measurements for the cosmic spatial curvature, which is related to the nature of cosmic space-time geometry, plays an important role in cosmology. On the basis of the Distance Sum Rule in the Friedmann-Lema{\^i}tre-Robertson-Walker metric, (distance ratio) measurements of strong gravitational lensing (SGL) systems together with distances from type Ia supernovae observations have been proposed to directly estimate the spatial curvature without any assumptions for the theories of gravity and contents of the universe. However, previous studies indicated that a spatially closed universe was strongly preferred. In this paper, we re-estimate the cosmic curvature with the latest SGL data which includes 163 well-measured systems. In addition, possible factors, e.g. combination of SGL data from different surveys and stellar mass of the lens galaxy, which might affect estimations for the spatial curvature, are considered in our analysis. We find that, except the case where only SGL systems from the Sloan Lens ACS Survey are considered, a spatially flat universe is consistently favored at very high confidence level by the latest observations. It is suggested that the increasing number of well-measured strong lensing events might significantly reduce the bias of estimation for the cosmic curvature.

[35]  arXiv:1912.01851 [pdf, other]

Title: A Variant Stellar-to-Nebular Dust Attenuation Ratio on Subgalactic and Galactic Scales

Authors: Zesen Lin, Xu Kong

Comments: Accepted for publication in ApJ. 28 pages, 17 figures

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

The state-of-the-art geometry models of star/dust suggest that dust attenuation toward nebular regions ($A_{V,gas}$) is always larger than that of stellar regions ($A_{V,star}$). Utilizing the newly released Integral Field Spectroscopic data from the MaNGA survey, we investigate whether and how the $A_{V,star}/A_{V,gas}$ ratio varies from subgalactic to galactic scales. On subgalactic scale, we report stronger correlation between $A_{V,star}$ and $A_{V,gas}$ for more active HII regions. The local $A_{V,star}/A_{V,gas}$ is found to have moderate non-linear correlations with three tracers of diffuse ionized gas (DIG) as well as indicators of gas-phase metallicity and ionization. DIG regions tend to have larger $A_{V,star}/A_{V,gas}$ compared to classic HII regions excited by young OB stars. Metal-poor regions with higher ionized level suffer much less nebular attenuation and thus have larger $A_{V,star}/A_{V,gas}$ ratios. A low-$A_{V,gas}$ and high-$A_{V,star}/A_{V,gas}$ sequence, which can be resolved into DIG-dominated and metal-poor regions, on the three BPT diagrams is found. Based on these observations, we suggest that besides geometry of star/dust, local physical conditions such as metallicity and ionized level also play an important role in determining the $A_{V,star}/A_{V,gas}$. On galactic scale, the global $A_{V,star}/A_{V,gas}$ ratio has strong correlation with stellar mass, moderate correlations with SFR and metallicity, and weak correlations with inclination and sSFR. Galaxies with larger $M_*$, higher SFR, and being more metal-rich tend to have smaller $A_{V,star}/A_{V,gas}$ ratios. Such correlations form a decreasing trend of $A_{V,star}/A_{V,gas}$ along the star-forming main sequence and mass-metallicity relation. The dust growth process accompanied with galaxy growth might be one plausible explanation of our observations.

[36]  arXiv:1912.01862 [pdf, ps, other]

Title: A study of the scaling relation $M_{\bullet }\propto R_{e}σ^{3}$ for supermassive black holes and an update of the corresponding theoretical model

Authors: T. Beltramonte, E. Benedetto, A. Feoli, A.L. Iannella

Comments: Accepted for publication in Astrophysics and Space Science

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

In this paper we want to compare the theoretical predictions of a law proposed by Feoli and Mancini, with the most recent experimental data about galaxies and Supermassive black holes. The physical principle behind this law is the transformation of the angular momentum of the interstellar material, which falls into the black hole, into the angular momentum of the radiation emitted in this process. Despite the simplicity of the model, this law shows an excellent agreement with the experimental data for early-type galaxies while a new approach is proposed for spirals.

[37]  arXiv:1912.01863 [pdf, other]

Title: Evolution of the Alfvén Mach number associated with coronal mass ejection shock

Authors: Ciara A. Maguire, Eoin P. Carley, Joseph McCauley, Peter T. Gallagher

Comments: 8 pages, 4 figures

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

The Sun regularly produces large-scale eruptive events, such as coronal mass ejections (CMEs) that can drive shock waves through the solar corona. Such shocks can result in electron acceleration and subsequent radio emission in the form of a type II radio burst. However, the early-phase evolution of shock properties and its relationship to type II burst evolution is still subject to investigation. Here we study the evolution of a CME-driven shock by comparing three commonly used methods of calculating the Alfv\'en Mach number ($M_A$), namely: shock geometry, a comparison of CME speed to a model of the coronal Alfv\'en speed, and the type II band-splitting method. We applied the three methods to the 2017 September 2 event, focusing on the shock wave observed in extreme ultraviolet (EUV) by the Solar Ultraviolet Imager (SUVI) on board GOES-16, in white-light by the Large Angle and Spectrometric Coronagraph (LASCO) on board SOHO, and the type II radio burst observed by the Irish Low Frequency Array (I-LOFAR). We show that the three different methods of estimating shock $M_A$ yield consistent results and provide a means of relating shock property evolution to the type II emission duration. The type II radio emission emerged from near the nose of the CME when $M_A$ was in the range 1.4-2.4 at a heliocentric distance of $\sim$1.6 $R_\odot$. The emission ceased when the CME nose reached $\sim$2.4 $R_\odot$, despite an increasing Alfv\'en Mach number (up to 4). We suggest the radio emission cessation is due to the lack of quasi-perpendicular geometry at this altitude, which inhibits efficient electron acceleration and subsequent radio emission.

[38]  arXiv:1912.01871 [pdf, other]

Title: Inverse reconstruction of jet structure from off-axis gamma-ray burst afterglows

Authors: Kazuya Takahashi, Kunihito Ioka

Comments: 15 pages, 9 figures. Comments welcome

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

The gravitational wave event GW170817 and the slowly-rising afterglows of short gamma-ray burst GRB 170817A clearly suggest that the GRB jet has an angular structure. However the actual jet structure remains unclear as different authors give different structures. We formulate a novel method to inversely reconstruct the jet structure from off-axis GRB afterglows, without assuming any functional form of the structure in contrast to the previous studies. The jet structure is uniquely determined from the rising part of a light curve for a given parameter set by integrating an ordinary differential equation, which is derived from the standard theory of GRB afterglows. Applying to GRB 170817A, we discover that a non-trivial hollow-cone jet is consistent with the observed afterglows, as well as Gaussian and power-law jets within errors, which implies the Blandford-Znajek mechanism or an ejecta-jet interaction. The current observations only constrain the jet core, not in principle the outer jet structure around the line of sight. More precise and high-cadence observations with our inversion method will fix the jet structure, providing a clue to the jet formation and propagation.

[39]  arXiv:1912.01880 [pdf, other]

Title: Unraveling The Complex Nature Of The Very High-Energy $γ$-Ray Blazar PKS 2155-304

Authors: Alicja Wierzcholska, Michael Zacharias, Felix Jankowsky, Stefan Wagner, H.E.S.S. Collaboration

Comments: Proceedings paper of "High Energy Phenomena in Relativistic Outflows VII - HEPRO VII", held 9-12 July 2019 at Facultat de F\'isica, Universitat de Barcelona, Spain; accepted by PoS

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

PKS 2155-304 is a blazar located in the Southern Hemisphere, monitored with the High Energy Stereoscopic System (H.E.S.S.) at very high energy (VHE, E>100 GeV) $\gamma$ rays every year since 2002. Thanks to the large data set collected in the VHE range and simultaneous coverage in optical, ultraviolet (UV), X-ray and high energy $\gamma$-ray ranges, this object is an excellent laboratory to study spectral and temporal variability in blazars. However, despite many years of dense monitoring, the nature of the variability observed in PKS 2155-304 remains puzzling. In this paper, we discuss the complex spectral and temporal variability observed in PKS 2155-304. The data discussed include VHE $\gamma$-ray data collected with H.E.S.S. between 2013 and 2016, complemented with multiwavelength (MWL) observations from Fermi-LAT, Swift-XRT, Swift-UVOT, SMARTS, and the ATOM telescope. During the period of monitoring, PKS 2155-304 was transitioning from its lower state to the flaring states, and exhibiting different flavors of outbursts. For the first time, orphan optical flare lasting a few months was observed. Correlation studies show an indication of correlation between the X-ray and VHE $\gamma$-ray fluxes. Interestingly, a comparison of optical and X-ray or VHE $\gamma$-ray fluxes does not show global correlation. However, two distinct tracks in the diagram were found, which correspond to the different flaring activity states of PKS 2155-304.

[40]  arXiv:1912.01894 [pdf, other]

Title: Identification of a Minimoon Fireball

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

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

Objects gravitationally captured by the Earth-Moon system are commonly called temporarily captured orbiters (TCOs), natural Earth satellites, or minimoons. TCOs are a crucially important subpopulation of near-Earth objects (NEOs) to understand because they are the easiest targets for future sample-return, redirection, or asteroid mining missions. Only one TCO has ever been observed telescopically, 2006 RH 120, and it orbited Earth for about 11 months. Additionally, only one TCO fireball has ever been observed prior to this study. We present our observations of an extremely slow fireball (codename DN160822_03) with an initial velocity of around 11.0 km s-1 that was detected by six of the high-resolution digital fireball observatories located in the South Australian region of the Desert Fireball Network. Due to the inherent dynamics of the system, the probability of the meteoroid being temporarily captured before impact is extremely sensitive to its initial velocity. We examine the sensitivity of the fireball's orbital history to the chosen triangulation method. We use the numerical integrator REBOUND to assess particle histories and assess the statistical origin of DN160822_03. From our integrations we have found that the most probable capture time, velocity, semimajor axis, NEO group, and capture mechanism vary annually for this event. Most particles show that there is an increased capture probability during Earth's aphelion and perihelion. In the future, events like these may be detected ahead of time using telescopes like the Large Synoptic Survey Telescope, and the pre-atmospheric trajectory can be verified.

[41]  arXiv:1912.01895 [pdf, other]

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

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

Comments: Submitted to AJ

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

For centuries extremely-long grazing fireball displays have fascinated observers and inspired people to ponder about their origins. The Desert Fireball Network (DFN) is the largest single fireball network in the world, covering about one third of Australian skies. This expansive size has enabled us to capture a majority of the atmospheric trajectory of a spectacular grazing event that lasted over90 seconds, penetrated as deep as ~58.5km, and traveled over 1,300 km through the atmosphere before exiting back into interplanetary space. Based on our triangulation and dynamic analyses of the event, we have estimated the initial mass to be at least 60 kg, which would correspond to a30 cm object given a chondritic density (3500 kg m-3). However, this initial mass estimate is likely a lower bound, considering the minimal deceleration observed in the luminous phase. The most intriguing quality of this close encounter is that the meteoroid originated from an Apollo-type orbit and was inserted into a Jupiter-family comet (JFC) orbit due to the net energy gained during the close encounter with the Earth. Based on numerical simulations, the meteoroid will likely spend ~200kyrs on a JFC orbit and have numerous encounters with Jupiter, the first of which will occur in January-March 2025. Eventually the meteoroid will likely be ejected from the Solar System or be flung into a trans-Neptunian orbit.

[42]  arXiv:1912.01897 [pdf, other]

Title: The Large Amplitude X-ray Variability in NGC 7589: Possible Evidence for Accretion Mode Transition

Authors: Zhu Liu, He-Yang Liu, Huaqing Cheng, Erlin Qiao, Weimin Yuan (NAOC)

Comments: 10 pages, 2 figures, resubmitted to MNRAS after revision

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

We report the discovery of large amplitude X-ray variability in the low luminosity AGN (LLAGN) MGC 7589, and present possible observational evidence for accretion mode transition in this source. Long-term X-ray flux variations by a factor of more than 50 are found using X-ray data obtained by Swift/XRT and XMM-Newton over 17 years. Results of long-term monitoring data in the UV, optical and infrared bands over ~20 years are also presented. The Eddington ratio increased from $10^{-3}$ to $\sim0.13$, suggesting a transition of the accretion flow from an ADAF to a standard thin accretion disc. Further evidence supporting the thin disc in the high luminosity state is found by the detection of a significant soft X-ray component in the X-ray spectrum. The temperature of this component ($\sim19^{+15}_{-7}$eV, fitted with a blackbody model) is in agreement with the predicted temperature of the inner region for a thin disc around a black hole (BH) with mass of $\sim10^{7}\,M_{\mathrm{Sun}}$. These results may indicate that NGC 7589 had experienced accretion mode transition over a timescale of a few years, suggesting the idea that similar accretion processes are at work for massive black hole and black hole X-ray binaries.

[43]  arXiv:1912.01900 [pdf, other]

Title: A network of precision gravimeters as a detector of matter with feeble nongravitational coupling

Authors: Wenxiang Hu, Matthew Lawson, Dmitry Budker, Nataniel L. Figueroa, Derek F. Jackson Kimball, Allen P. Mills Jr., Christian Voigt

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

Hidden matter that interacts only gravitationally would oscillate at characteristic frequencies when trapped inside of Earth. For small oscillations near the center of the Earth, these frequencies are around 300 $\mu$Hz. Additionally, signatures at higher harmonics would appear because of the non-uniformity of Earth's density. In this work, we use data from a global network of gravimeters of the International Geodynamics and Earth Tide Service (IGETS) to look for these hypothetical trapped objects. We find no evidence for such objects with masses of up to on the order of 10$^{13}$ kg. It may be possible to improve the sensitivity of the search by several orders of magnitude via better understanding of the terrestrial noise sources and more advanced data analysis.

[44]  arXiv:1912.01911 [pdf, other]

Title: Global Site Selection for Astronomy

Authors: N. Aksaker, S.K. Yerli, M.A. Erdoğan, Z. Kurt, K. Kaba, M. Bayazit, C. Yesilyaprak

Comments: 19 Pages, 4 Figures, 7 tables, Submitted to MNRAS

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

A global site selection for astronomy was performed with 1 km spatial resolution ($\sim$ 1 Giga pixel in size) using long term and up-to-date datasets to classify the entire terrestrial surface on the Earth. Satellite instruments are used to get the following datasets of Geographical Information System (GIS) layers: Cloud Coverage, Digital Elevation Model, Artificial Light, Precipitable Water Vapor, Aerosol Optical Depth, Wind Speed and Land Use -- Land Cover. A Multi Criteria Decision Analysis (MCDA) technique is applied to these datasets creating four different series where each layer will have a specific weight. We introduce for the first time a "Suitability Index for Astronomical Sites" namely, SIAS. This index can be used to find suitable locations and to compare different sites or observatories. Mid-western Andes in South America and Tibetan Plateau in west China were found to be the best in all SIAS Series. Considering all the series, less than 3 \% of all terrestrial surfaces are found to be the best regions to establish an astronomical observatory. In addition to this, only approximately 10 \% of all current observatories are located in good locations in all SIAS series. Amateurs, institutions or countries aiming to construct an observatory could create a short-list of potential site locations using layout of SIAS values for each country without spending time and budget.

[45]  arXiv:1912.01921 [pdf, other]

Title: Prospects for the characterization of the VHE emission from the Crab Nebula and Pulsar with the Cherenkov Telescope Array

Authors: Enrique Mestre, Emma de Oña Wilhelmi, Roberta Zanin, Diego F. Torres, Luigi Tibaldo

Comments: in press in MNRAS

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

The Cherenkov Telescope Array (CTA) will be the next generation instrument for the very high energy gamma-ray astrophysics domain. With its enhanced sensitivity in comparison with the current facilities, CTA is expected to shed light on a varied population of sources. In particular, we will achieve a deeper knowledge of the Crab nebula and pulsar, which are the best characterized pulsar wind nebula and rotation powered pulsar, respectively. We aim at studying the capabilities of CTA regarding these objects through simulations, using the main tools currently in development for the CTA future data analysis: Gammapy and ctools. We conclude that, even using conservative Instrument Response Functions, CTA will be able to resolve many uncertainties regarding the spectrum and morphology of the pulsar and its nebula. The large energy range covered by CTA will allow us to disentangle the nebula spectral shape among different hypotheses, corresponding to different underlying emitting mechanisms. In addition, resolving internal structures (smaller than ~ 0.02 degrees in size) in the nebula and unveiling their location, would provide crucial information about the propagation of particles in the magnetized medium. We used a theoretical asymmetric model to characterise the morphology of the nebula and we showed that if predictions of such morphology exist, for instance as a result of hydrodynamical or magneto-hydrodynamical simulations, it can be directly compared with CTA results. We also tested the capability of CTA to detect periodic radiation from the Crab pulsar obtaining a precise measurement of different light curves shapes.

[46]  arXiv:1912.01924 [pdf, other]

Title: Detection of Pristine Circumstellar Material of the Cassiopeia A Supernova

Authors: Bon-Chul Koo, Hyun-Jeong Kim, Heeyoung Oh, John C. Raymond, Sung-Chul Yoon, Yong-Hyun Lee, Daniel T. Jaffe

Comments: 18 pages, 7 figures

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

Cassiopeia A is a nearby young supernova remnant that provides a unique laboratory for the study of core-collapse supernova explosions. Cassiopeia A is known to be a Type IIb supernova from the optical spectrum of its light echo, but the immediate progenitor of the supernova remains uncertain. Here we report results of near-infrared, high-resolution spectroscopic observations of Cassiopeia A where we detected the pristine circumstellar material of the supernova progenitor. Our observations revealed a strong emission line of iron (Fe) from a circumstellar clump that has not yet been processed by the supernova shock wave. A comprehensive analysis of the observed spectra, together with an HST image, indicates that the majority of Fe in this unprocessed circumstellar material is in the gas phase, not depleted onto dust grains as in the general interstellar medium. This result is consistent with a theoretical model of dust condensation in material that is heavily enriched with CNO-cycle products, supporting the idea that the clump originated near the He core of the progenitor. It has been recently found that Type IIb supernovae can result from the explosion of a blue supergiant with a thin hydrogen envelope, and our results support such a scenario for Cassiopeia A.

[47]  arXiv:1912.01925 [pdf, ps, other]

Title: NaCo polarimetric observations of Sz 91 transitional disk: a remarkable case of dust filtering

Authors: Karina Maucó, Johan Olofsson, Hector Canovas, Matthias R. Schreiber, Valentin Christiaens, Amelia Bayo, Alice Zurlo, Claudio Cáceres, Christophe Pinte, Eva Villaver, Julien H. Girard, Lucas Cieza, Matías Montesinos

Comments: 14 pages, 8 figures, accepted for publication in MNRAS

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

We present polarized light observations of the transitional disk around Sz 91 acquired with VLT/NaCo at $H$ (1.7$\mu$m) and $K_s$ (2.2$\mu$m) bands. We resolve the disk and detect polarized emission up to $\sim$0."5 ($\sim$80 au) along with a central cavity at both bands. We computed a radiative transfer model that accounts for the main characteristics of the polarized observations. We found that the emission is best explained by small, porous grains distributed in a disk with a $\sim$45 au cavity. Previous ALMA observations have revealed a large sub-mm cavity ($\sim$83 au) and extended gas emission from the innermost (<16 au) regions up to almost 400 au from the star. Dynamical clearing by multiple low-mass planets arises as the most probable mechanism for the origin of Sz 91's peculiar structure. Using new $L'$ band ADI observations we can rule out companions more massive than $M_p$ $\geq$ 8 $M_\mathrm{Jup}$ beyond 45 au assuming hot-start models. The disk is clearly asymmetric in polarized light along the minor axis, with the north side brighter than the south side. Differences in position angle between the disk observed at sub-mm wavelengths with ALMA and our NaCo observations were found. This suggests that the disk around Sz 91 could be highly structured. Higher signal-to-noise near-IR and sub-mm observations are needed to confirm the existence of such structures and to improve the current understanding in the origin of transitional disks.

[48]  arXiv:1912.01986 [pdf, other]

Title: From the Sun to solar-like stars: how does the solar modelling problem affect our studies of solar-like oscillators?

Authors: G. Buldgen, C. Pezzotti, M. Farnir, S.J.A.J. Salmon, P. Eggenberger

Comments: To appear in the proceedings of the conference "Stars and their variability observed from space" held in Vienna in August 2019

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

Since the first observations of solar oscillations in 1962, helioseismology has probably been one of the most successful fields of astrophysics. Besides the improvement of observational data, solar seismologists developed sophisticated techniques to infer the internal structure of the Sun. Back in 1990s these comparisons showed a very high agreement between solar models and the Sun. However, the downward revision of the CNO surface abundances in the Sun in 2005, confirmed in 2009, induced a drastic reduction of this agreement leading to the so-called solar modelling problem. More than ten years later, in the era of the space-based photometry missions which have established asteroseismology of solar-like stars as a standard approach to obtain their masses, radii and ages, the solar modelling problem still awaits a solution. We will briefly present the results of new helioseismic inversions, discuss the current uncertainties of solar models and possible solutions to the solar modelling problem. We will also discuss how the solar problem can have significant implications for asteroseismology as a whole by discussing the modelling of the exoplanet-host star Kepler-444, thus impacting the fields requiring a precise and accurate knowledge of stellar masses, radii and ages, such as Galactic archaeology and exoplanetology.

[49]  arXiv:1912.02003 [pdf, other]

Title: Global Helioseismology

Authors: G. Buldgen

Comments: To appear in the proceedings of the meeting "How Much do we Trust Stellar Models?" held in Li\`ege in Sept 2018

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

Helioseismology is one of the most successful fields of astrophysics. The observation and characterization of solar oscillation has allowed solar seismologists to study the internal structure and dynamics of the Sun with unprecedented thoroughness. Ground-based networks and dedicated space missions have delivered data of exquisite quality, enabling the development of sophisticated inference techniques. The achievements of the fields count, amongst other, the determination of solar photospheric helium abundance, unacessible to spectroscopic constraints, the precise positioning of the base of the convective zone and the demonstration of the importance of microscopic diffusion in stellar radiative regions. Helioseismology played also a key role in validating the framework used to compute solar and stellar models and played an important role in the so-called solar neutrino problem. In the current era of astrophysics, with the increasing importance of asteroseismology to precisely characterize stars, the Sun still plays a crucial calibration role, acting as a benchmark for stellar models. With the revision of the solar abundances and the current discussions related to radiative opacity computations, the role of the Sun as a laboratory of fundamental physics is undisputable. In this brief review, I will discuss some of the inference techniques developed in the field of helioseismology, dedicated to the exploitation of the solar global oscillation modes.

[50]  arXiv:1912.02027 [pdf, ps, other]

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

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

Comments: MNRAS, in press: 8 pages, 4 figures

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

Recent analyses of the broad spectral energy distributions (SED) of extensive lobes of local radio-galaxies have confirmed the leptonic origin of their Fermi/LAT gamma-ray emission, significantly constraining the level of hadronic contribution. SED of distant (D > 125 Mpc) radio-galaxy lobes are currently limited to the radio and X-ray bands, hence give no information on the presence of non-thermal (NT) protons but are adequate to describe the properties of NT electrons. Modeling lobe radio and X-ray emission in 3C 98, Pictor A, DA 240, Cygnus A, 3C 326, and 3C 236, we fully determine the properties of intra-lobe NT electrons and estimate the level of the related gamma-ray emission from Compton scattering of the electrons off the superposed Cosmic Microwave Background, Extragalactic Background Light, and source-specific radiation fields.

[51]  arXiv:1912.02056 [pdf, other]

Title: Exploring the latitude and depth dependence of solar Rossby waves using ring-diagram analysis

Authors: B. Proxauf, L. Gizon, B. Löptien, J. Schou, A. C. Birch, R. S. Bogart

Comments: Submitted to A and A

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

Global-scale Rossby waves have recently been unambiguously identified on the Sun. Here we study the latitude and depth dependence of the Rossby wave eigenfunctions. By applying helioseismic ring-diagram analysis and granulation tracking to SDO/HMI observations, we compute maps of the radial vorticity of flows in the upper solar convection zone (down to depths of more than 16 Mm). We use a Fourier transform in longitude to separate the different azimuthal orders m in the range $3\le m\le15$. At each $m$ we obtain the phase and amplitude of the Rossby waves as a function of depth using the helioseismic data. At each m we also measure the latitude dependence of the eigenfunctions by calculating the covariance between the equator and other latitudes. We then study the horizontal and radial dependences of the radial vorticity eigenfunctions. The horizontal eigenfunctions are complex. As observed previously, the real part peaks at the equator and switches sign near $\pm 30^\circ$, thus the eigenfunctions show significant non-sectoral contributions. The imaginary part is smaller than the real part. The phase of the radial eigenfunctions varies by only roughly $\pm 5^\circ$ over the top 15 Mm. The amplitude of the radial eigenfunctions decreases by about 10% from the surface down to 8 Mm (the region where ring-diagram analysis is most reliable, as seen by comparing with the rotation rate measured by global-mode seismology). The radial dependence of the radial vorticity eigenfunctions deduced from ring-diagram analysis is consistent with a power-law down to 8 Mm and is unreliable at larger depths. However, the observations provide only weak constraints on the power-law exponents. For the real part, the latitude dependence of the eigenfunctions is consistent with previous work (using granulation tracking). The imaginary part is smaller than the real part but significantly nonzero.

[52]  arXiv:1912.02086 [pdf, other]

Title: Constraining the Milky Way Mass Profile with Phase-Space Distribution of Satellite Galaxies

Authors: Zhao-Zhou Li, Yong-Zhong Qian, Jiaxin Han, Ting S. Li, Wenting Wang, Y. P. Jing

Comments: 20 pages, 12 figures, 4 tables; submitted to ApJ, comments are welcome

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

We estimate the Milky Way (MW) halo properties using satellite kinematic data including the latest measurements from Gaia DR2. With a simulation-based 6D phase-space distribution function (DF) of satellite kinematics, we can infer halo properties efficiently and without bias, and handle the selection function and measurement errors rigorously in the Bayesian framework. Applying our DF from the EAGLE simulation to 28 satellites, we obtain an MW halo mass of $M=1.23_{-0.18}^{+0.21}\times 10^{12} M_\odot$ and a concentration of $c=9.4_{ -2.1}^{ +2.8}$ with the prior based on the $M$-$c$ relation. The inferred mass profile is consistent with previous measurements, but with better precision and reliability due to the improved methodology and data. Potential improvement is illustrated by combining satellite data and stellar rotation curves. Using our EAGLE DF and best-fit MW potential, we provide much more precise estimates of kinematics for those satellites with uncertain measurements. Compared to the EAGLE DF, which matches the observed satellite kinematics very well, the DF from the semi-analytical model based on the dark-matter-only simulation Millennium II (SAM-MII) over-represents satellites with small radii and velocities. We attribute this difference to less disruption of satellites with small pericenter distances in the SAM-MII simulation. By varying the disruption rate of such satellites in this simulation, we estimate a $\sim 5\%$ scatter in the inferred MW halo mass among hydrodynamics-based simulations.

[53]  arXiv:1912.02087 [pdf, other]

Title: Third components with elliptical orbits in the eclipsing binaries

Authors: D.E. Tvardovskyi, V.I. Marsakova, I.L. Andronov

Comments: 13 pages, 10 figures, subm

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

In our research, we studied 9 eclipsing binary stars: AR Lac, U CrB, S Equ, SU Boo, VV UMa, WW Gem, YY Eri, V0404 Lyr, HP Aur. We collected large sets of moments of minima from BRNO and observational data from AAVSO databases. Then, we obtained moments of minima for AAVSO observations (totally - 397 minima) using method of approximation with symmetric polynomial, realized in software MAVKA. This software was provided by Kateryna D. Andrych and Ivan L. Andronov. After we combined obtained moments of minima with data taken from BRNO and plotted O-C diagrams. For all stars these diagrams represented sinusoidal-like oscillations with superposition of linear (for SU Boo, VV UMa, WW Gem, V0404 Lyr and HP Aur) or parabolic trend (for AR Lac, U CrB, S Equ and YY Eri). The oscillations could be described as presence of the third component, which does not take part in eclipses, but causes the well-known light-time effect (LTE). That effect could be easily detected using long data series of observations. However, the oscillations have clear asymmetry, which we interpreted as elliptical shape of the third components orbit. Parabolic trend we explained as mass transfer between components of binary system. For all stars we computed minimal possible mass of the third component. In addition, we developed our own code in computed language Python and using it we computed orbital elements of the third component. Moreover, for stars with parabolic trend we calculated rate of the mass transfer. Finally, for all computed values we estimated errors.

[54]  arXiv:1912.02113 [pdf, other]

Title: Diagnosing pulsar winds in black-widow, redback, and other binary millisecond pulsar systems

Authors: Anne Zilles, Kumiko Kotera, Rene Rohrmann, Leandro Althaus

Comments: accepted for publication in Monthly Notices of the Royal Astronomical Society Main Journal

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

Binary systems composed of a recycled millisecond pulsar and a stellar companion in close orbit could be excellent sites to diagnose pulsar winds. In such systems, the pulsar outflow irradiates and heats up the companion atmosphere, which can lead to the observation of strong day/night modulations in temperature. We demonstrate with particle shower simulations that the particle energy of the wind affects the heating depth in the atmosphere: the wind heat can be deposited above or below the photosphere, leading to different signatures in the observed spectra. We apply our method to four specific systems: We find that systems with cool night side companions showing strong temperature variations can give interesting lower limits on the particle energy in the winds. In particular, if the companion night side of PSR B1957+20 were to be suddenly irradiated, deep heating would only take place if particles with energy > 100 TeV were present. Observational evidence of deep heating in this system thus suggests that i) such particles exist in the pulsar wind and/or ii) binary evolution non-trivially takes the companion to the observed temperature asymmetry. Besides, the observed temperature difference can be maintained only with particle energies of the order of 100 MeV.

[55]  arXiv:1912.02117 [pdf, ps, other]

Title: Dust masses and grain size distributions of a sample of Galactic pulsar wind nebulae

Authors: F. D. Priestley, M. J. Barlow, I. De Looze, H. Chawner

Comments: 13 pages, 10 figures. MNRAS accepted 04/12/19

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

We calculate dust spectral energy distributions (SEDs) for a range of grain sizes and compositions, using physical properties appropriate for five pulsar wind nebulae (PWNe) from which dust emission associated with the ejecta has been detected. By fitting the observed dust SED with our models, with the number of grains of different sizes as the free parameters, we are able to determine the grain size distribution and total dust mass in each PWN. We find that all five PWNe require large ($\ge 0.1 \, {\rm \mu m}$) grains to make up the majority of the dust mass, with strong evidence for the presence of micron-sized or larger grains. Only two PWNe contain non-negligible quantities of small ($<0.01 \, {\rm \mu m}$) grains. The size distributions are generally well-represented by broken power laws, although our uncertainties are too large to rule out alternative shapes. We find a total dust mass of $0.02-0.28 \, {\rm M}_\odot$ for the Crab Nebula, depending on the composition and distance from the synchrotron source, in agreement with recent estimates. For three objects in our sample, the PWN synchrotron luminosity is insufficient to power the observed dust emission, and additional collisional heating is required, either from warm, dense gas as found in the Crab Nebula, or higher temperature shocked material. For G$54.1$+$0.3$, the dust is heated by nearby OB stars rather than the PWN. Inferred dust masses vary significantly depending on the details of the assumed heating mechanism, but in all cases large mass fractions of micron-sized grains are required.

[56]  arXiv:1912.02129 [pdf, ps, other]

Title: Candidate Hypervelocity Red Clump Stars in the Galactic Bulge Found Using the VVV and Gaia Surveys

Authors: Alonso Luna (1, 2), Dante Minniti (2, 3 and 4), Javier Alonso-García (3 and 5) ((1) Instituto de Astronomía, Universidad Nacional Autónoma de México, México, (2) Depto. de Ciencias Físicas, Facultad de Ciencias Exactas, Universidad Andres Bello, Chile, (3) Millennium Institute of Astrophysics, Chile, (4) Vatican Observatory, Italy, (5) Centro de Astronomía (CITEVA), Universidad de Antofagasta, Chile)

Comments: 9 pages, 2 figures, 4 subfigures, 3 tables. Accepted for publication in ApJL

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

We propose a new way to search for hypervelocity stars in the Galactic bulge, by using red clump (RC) giants, that are good distance indicators. The 2nd Gaia Data Release and the near-IR data from the VISTA Variables in the Via Lactea (VVV) Survey led to the selection of a volume limited sample of 34 bulge RC stars. A search in this combined data set leads to the discovery of seven candidate hypervelocity red clump stars in the Milky Way bulge. Based on this search we estimate the total production rate of hypervelocity RC stars from the central supermassive black hole (SMBH) to be $N_{HVRC} = 3.26 \times 10^{-4} $ yr$^{-1}$. This opens up the possibility of finding larger samples of hypervelocity stars in the Galactic bulge using future surveys, closer to their main production site, if they are originated by interactions of binaries with the central SMBH.

[57]  arXiv:1912.02132 [pdf]

Title: High-resolution reflection spectra for Proxima b and Trappist-1e models for ELT observations

Authors: Zifan Lin, Lisa Kaltenegger

Comments: 13 pages, 6 figures, 2 tables. To be published in MNRAS

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

The closest stars that harbor potentially habitable planets are cool M-stars. Upcoming ground- and space-based telescopes will be able to search the atmosphere of such planets for a range of chemicals. To facilitate this search and to inform upcoming observations, we model the high-resolution reflection spectra of two of the closest potentially habitable exoplanets for a range of terrestrial atmospheres and surface pressures for active and inactive phases of their host stars for both oxic and anoxic conditions: Proxima b, the closest potentially habitable exoplanet, and Trappist-1e, one of 3 Earth-size planets orbiting in the Habitable Zone of Trappist-1. We find that atmospheric spectral features, including biosignatures like O2 in combination with a reduced gas like CH4 for oxic atmospheres, as well as climate indicators like CO2 and H2O for all atmospheres, show absorption features in the spectra of Proxima b and Trappist-1e models. However for some features like oxygen, high-resolution observations will be critical to identify them in a planet's reflected flux. Thus these two planets will be among the best targets for upcoming observations of potential Earth-like planets in reflected light with planned Extremely Large Telescopes.

[58]  arXiv:1912.02133 [pdf, other]

Title: Observations and 3D MHD Modeling of a Confined Helical Jet Launched by a Filament Eruption

Authors: Lauren Doyle, Peter F. Wyper, Eamon Scullion, James A. McLaughlin, Gavin Ramsay, J. Gerard Doyle

Comments: Accepted for publication in ApJ. 21 pages, 14 figures and 6 animations which will be avaliable in the published version

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

We present a detailed analysis of a confined filament eruption and jet associated with a C1.5 class solar flare. Multi-wavelength observations from GONG and SDO reveal the filament forming over several days following the emergence and then partial cancellation of a minority polarity spot within a decaying bipolar active region. The emergence is also associated with the formation of a 3D null point separatrix that surrounds the minority polarity. The filament eruption occurs concurrent with brightenings adjacent to and below the filament, suggestive of breakout and flare reconnection, respectively. The erupting filament material becomes partially transferred into a strong outflow jet (~ 60 km/s) along coronal loops, becoming guided back towards the surface. Utilising high resolution H$\alpha$ observations from SST/CRISP, we construct velocity maps of the outflows demonstrating their highly structured but broadly helical nature. We contrast the observations with a 3D MHD simulation of a breakout jet in a closed-field background and find close qualitative agreement. We conclude that the suggested model provides an intuitive mechanism for transferring twist/helicity in confined filament eruptions, thus validating the applicability of the breakout model not only to jets and coronal mass ejections but also to confined eruptions and flares.

[59]  arXiv:1912.02137 [pdf, other]

Title: Saturn's Probable Interior: An Exploration of Saturn's Potential Interior Density Structures

Authors: Naor Movshovitz, Jonathan J. Fortney, Chris Mankovich, Daniel Thorngren, Ravit Helled

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

The gravity field of a giant planet is typically our best window into its interior structure and composition. Through comparison of a model planet's calculated gravitational potential with the observed potential, inferences can be made about interior quantities, including possible composition and the existence of a core. Necessarily, a host of assumptions go into such calculations, making every inference about a giant planet's structure strongly model dependent. In this work we present a more general picture by setting Saturn's gravity field, as measured during the \emph{Cassini} Grand Finale, as a likelihood function driving a Markov-Chain Monte Carlo exploration of the possible interior density profiles. The result is a posterior distribution of the interior structure that is not tied to assumed composition, thermal state, or material equations of state. Constraints on interior structure derived in this Bayesian framework are necessarily less informative, but are also less biased and more general. These empirical and probabilistic constraints on the density structure are our main data product which we archive for continued analysis. We find that the outer half of Saturn's radius is relatively well constrained, and we interpret our findings as suggesting a significant metal enrichment, in line with atmospheric abundances from remote sensing. As expected, the inner half of Saturn's radius is less well-constrained by gravity, but we generally find solutions that include a significant density enhancement, which can be interpreted as a core, although this core is often lower in density and larger in radial extent than typically found by standard models. This is consistent with a dilute core and/or composition gradients.

[60]  arXiv:1912.02170 [pdf, other]

Title: Evolution of the radius valley around low mass stars from $Kepler$ and $K2$

Authors: Ryan Cloutier, Kristen Menou

Comments: Submitted to AAS journals. 23 pages. Table data included as csv files in source. 15 figures including 6 interactive figures when viewed in Adobe Acrobat

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

We present calculations of the occurrence rate of small close-in planets around low mass dwarf stars using the known planet populations from the $Kepler$ and $K2$ missions. Applying completeness corrections clearly reveals the radius valley in the maximum a-posteriori occurrence rates as a function of orbital separation and planet radius. We measure the slope of the valley to be $r_{p,\text{valley}} \propto F^{-0.060\pm 0.025}$ which bears the opposite sign from that measured around Sun-like stars thus suggesting that thermally driven atmospheric mass loss may not dominate the evolution of planets in the low stellar mass regime or that we are witnessing the emergence of a separate channel of planet formation. The latter notion is supported by the relative occurrence of rocky to non-rocky planets increasing from $0.5\pm 0.1$ around mid-K dwarfs to $8.5\pm 4.6$ around mid-M dwarfs. Furthermore, the center of the radius valley at $1.54\pm 0.16$ R$_{\oplus}$ is shown to shift to smaller sizes with decreasing stellar mass in agreement with physical models of photoevaporation, core-powered mass loss, and gas-poor formation. Although current measurements are insufficient to robustly identify the dominant formation pathway of the radius valley, such inferences may be obtained by $TESS$ with $\mathcal{O}(85,000)$ mid-to-late M dwarfs observed with 2-minute cadence. The measurements presented herein also precisely designate the subset of planetary orbital periods and radii that should be targeted in radial velocity surveys to resolve the rocky to non-rocky transition around low mass stars.

[61]  arXiv:1912.02171 [pdf, other]

Title: Small-scale primordial fluctuations in the 21cm Dark Ages signal

Authors: Philippa S. Cole, Joseph Silk

Comments: 14 pages, 9 figures

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

Primordial black hole production in the mass range $10-10^4 \,{\rm M_\odot}$ is motivated respectively by interpretations of the LIGO/Virgo observations of binary black hole mergers and by their ability to seed intermediate black holes which would account for the presence of supermassive black holes at very high redshift. Their existence would imply a boost in the primordial power spectrum if they were produced by overdensities reentering the horizon and collapsing after single-field inflation. This, together with their associated Poisson fluctuations would cause a boost in the matter power spectrum on small scales. In fact, any evidence of extra power above that of an almost scale-invariant primordial power spectrum on small scales would suggest a non-single-field slow-roll model of inflation, whether or not primordial black holes were produced. The extra power could become potentially observable in the 21cm power spectrum on scales around $k\sim0.1 - 50\,{\rm Mpc^{-1}}$ either with the new generation of filled low frequency interferometers. We explicitly include the contribution from primordial fluctuations in our prediction of the 21cm signal which has been previously neglected, by constructing primordial power spectra motivated by single-field models of inflation that would produce extra power on small scales. We find that depending on the mass and abundance of primordial black holes, it is important to include this contribution from the primordial fluctuations, so as not to underestimate the 21cm signal. Evidently our predictions of detectability, which lack any modelling of foregrounds, are unrealistic, but we hope that they will motivate improved cleaning algorithms that can enable us to access this intriguing corner of PBH-motivated parameter space.

Cross-lists for Thu, 5 Dec 19

[62]  arXiv:1806.06716 (cross-list from q-bio.PE) [pdf, other]

Title: Theory of chemical evolution of molecule compositions in the universe, in the Miller-Urey experiment and the mass distribution of interstellar and intergalactic molecules

Authors: Stuart A. Kauffman, David P. Jelenfi, Gabor Vattay

Journal-ref: Journal of Theoretical Biology 2019

Subjects: Populations and Evolution (q-bio.PE); Cosmology and Nongalactic Astrophysics (astro-ph.CO); Solar and Stellar Astrophysics (astro-ph.SR); Biological Physics (physics.bio-ph)

Chemical evolution is essential in understanding the origins of life. We present a theory for the evolution of molecule masses and show that small molecules grow by random diffusion and large molecules by a preferential attachment process leading eventually to life's molecules. It reproduces correctly the distribution of molecules found via mass spectroscopy for the Murchison meteorite and estimates the start of chemical evolution back to 12.8 billion years following the birth of stars and supernovae. From the Frontier mass between the random and preferential attachment dynamics the birth time of molecule families can be estimated. Amino acids emerge about 165 million years after chemical elements emerge in stars. Using the scaling of reaction rates with the distance of the molecules in space we recover correctly the few days emergence time of amino acids in the Miller-Urey experiment. The distribution of interstellar and extragalactic molecules are both consistent with the evolutionary mass distribution, and their age is estimated to 108 and 65 million years after the start of evolution. From the model, we can determine the number of different molecule compositions at the time of the emergence of Earth to be 1.6 million and the number of molecule compositions in interstellar space to a mere 719 species.

[63]  arXiv:1912.00090 (cross-list from gr-qc) [pdf, other]

Title: T-Model Inflation and Bouncing Cosmology

Authors: David Sloan, Konstantinos Dimopoulos, Sotirios Karamitsos

Comments: 27 pages, 6 figures

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

We examine the dynamics of a closed cosmology whose matter source is that of a conformally coupled scalar field with a broken ${\rm SO}(1,1)$ symmetry, which correspond to the $\alpha$-attractors proposed by Linde and Kallosh. Following a field redefinition, such models give rise to "T-model" inflationary potentials, whose dynamics provide both an inflationary phase and a classical bounce. We show that the universe can undergo bounces far from the regime of quantum gravity. We analyse perturbations on this background with particular attention given to the effects of a double-bouncing scenario (with rapid recollapse between bounces) on the long wavelength modes. We demonstrate that the predictions of such models agree well with observations and might explain the suppression of power in the low multiples of the CMB.

[64]  arXiv:1912.01654 (cross-list from gr-qc) [pdf, other]

Title: On generality of Starobinsky and Higgs inflation in the Jordan frame

Authors: Swagat S. Mishra, Daniel Müller, Aleksey V. Toporensky

Comments: 14 pages, 8 figures

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

We revisit the problem of generality of Starobinsky and Higgs inflation. The known results obtained in the Einstein frame are generalized for the case of an arbitrary initial energy of the scalar field. These results are compared with the results obtained directly in the Jordan frame. We demonstrate that the qualitative picture of initial conditions zone in the $(\phi, \dot \phi)$ plane, which leads to sufficient amount of inflation, is quite similar for both the frames in the case of Higgs inflation. For Starobinsky inflation, the conformal transformation between the frames relates the geometrical variables in the Jordan frame with the properties of an effective scalar field in the Einstein frame. We show that the transformation $(H, R) \to (\phi, \dot \phi)$ is not regular everywhere, leading to some peculiarities in the zone of good initial conditions in the $(H, R)$ plane.

[65]  arXiv:1912.01758 (cross-list from hep-ph) [pdf, other]

Title: Generalized Blind Spots for Dark Matter Direct Detection in the 2HDM

Authors: M. E. Cabrera, J. A. Casas, A. Delgado, S. Robles

Comments: 15 pages, 5 figures, 2 tables

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

In this paper we study the presence of generalized blind spots, i.e. regions of the parameter space where the spin-independent cross section for dark matter direct detection is suppressed, in the context of a generic 2HDM and a minimal fermionic Higgs-portal dark sector. To this end, we derive analytical expressions for the couplings of the dark matter to the light and heavy Higgses, and thus for the blind spot solutions. Unlike the case of a standard Higgs sector, blind spots can occur even without a cancellation between different contributions, while keeping unsuppressed and efficient the annihilation processes in the early Universe involving Higgs states. As a consequence, the allowed parameter space is dramatically enhanced.

[66]  arXiv:1912.01768 (cross-list from gr-qc) [pdf, ps, other]

Title: Cosmological evolution of viable models in the generalized scalar-tensor theory

Authors: Shun Arai, Purnendu Karmakar, Atsushi Nishizawa

Comments: 43 pages, 20 figures

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

We investigate the parameter distributions of the viable generalized scalar-tensor theory with conventional dust matter after GW170817 in a model-independent way. We numerically construct the models by computing the time evolution of a scalar field, which leads to a positive definite second-order Hamiltonian and are consistent with the observed Hubble parameter. We show the model parameter distributions in the degenerate higher-order scalar-tensor (DHOST) theory, and its popular subclasses, e.g., Horndeski and GLPV theories, etc.. We find that 1) the Planck mass run rate, $\alpha_M$, is insensitive to distinguish the theories. 2) the kinetic-braiding parameter, $\alpha_B$, clearly discriminates the models from those of the Horndeski theory, 3) the parameters for the higher-order theories, $\alpha_H$ and $\beta_1$, are relatively smaller in magnitude (by several factors) than $\alpha_M$ and $\alpha_B$, but can still be used for discriminating the theories except for the GLPV theory. Based on the above three facts, we propose a minimal set of parameters that sensibly distinguishes the subclasses of DHOST theories, ($\alpha_M$, $\alpha_B-\alpha_M/2$, $\beta_1$).

[67]  arXiv:1912.01783 (cross-list from physics.pop-ph) [pdf]

Title: Searching for a standard Drake equation

Authors: Jose Antonio Molina Molina

Comments: 15 pages, 3 tables

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

In the 20th century the scientific search for extraterrestrial intelligence began, and the Drake equation was proposed to estimate the number of extraterrestrial species humanity could attempt to detect, N. This paper discusses the need to update and standardize this equation. A new and more accurate expression is deduced which contains the classic equation as a particular case, and its advantages are discussed. A necessary condition is also stated for its use in scientific contexts: if N is defined as the total number of civilizations like ours then N = 1, given that we exist, and consequently the working hypothesis of the SETI project can be expressed as N>1. In this case, the Drake equation is being applied in a scientific way, because it is trying to test a hypothesis based on evidence.

[68]  arXiv:1912.01919 (cross-list from hep-th) [pdf, other]

Title: Superconformal Generalizations of $R^n$--$φ^p$ Interpolating Inflationary Theories

Authors: Sibel Boran, Emre Onur Kahya, Nese Ozdemir, Mehmet Ozkan, Utku Zorba

Comments: v1. 7 pages, 1 figure

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

We present the supersymmetric completion of the auxiliary vector modified polynomial $f(R)$ theories that interpolate between the polynomial $f(R)$ theories and chaotic inflation with the power-law potential $V(\phi) \propto \phi^p$. The supersymmetrization is achieved in two steps: First, we introduce a superconformal theory for three chiral multiplets by choosing a conformal K\"ahler potential and a conformal superpotential. In the second step, we use one of the chiral multiplets to compensate for the superconformal symmetries and achieve the K\"ahler potential and the superpotential while the other two are used to realize inflation with a stable inflationary trajectory. The stability of the inflationary trajectory requires certain deformations to the K\"ahler potential which we discuss their compatibility against the inflationary observables from the latest Planck data.

[69]  arXiv:1912.02034 (cross-list from hep-ph) [pdf, other]

Title: Precise yield of high-energy photons from Higgsino dark matter annihilation

Authors: Martin Beneke, Caspar Hasner, Kai Urban, Martin Vollmann

Comments: 30 pages, 5 figures

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

The impact of electroweak Sudakov logarithms on the endpoint of the photon spectrum for wino dark matter annihilation was studied intensively over the last several years. In this work, we extend these results to Higgsino dark matter $\chi_1^0$. We achieve NLL' resummation accuracy for narrow and intermediate spectral energy resolutions, of order $m_W^2 / m_\chi$ and $m_W$, respectively. This is the most accurate prediction to date for the yield of high-energy $\gamma$-rays from $\chi_1^0 \chi_1^0 \to \gamma + X$ annihilation for the energy resolutions realized by current and next-generation telescopes. We also discuss for the first time the effect of power corrections in $m_W/m_\chi$ in this context and argue why they are not sizeable.

[70]  arXiv:1912.02038 (cross-list from physics.ins-det) [pdf]

Title: Design and Status of JUNO

Authors: Hans Theodor Josef Steiger (on behalf of the JUNO Collaboration)

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

The Jiangmen Underground Neutrino Observatory (JUNO) is a 20 kton multi-purpose liquid scintillator detector currently being built in a dedicated underground laboratory in Jiangmen (PR China). JUNO' s main physics goal is to determine the neutrino mass ordering using electron anti-neutrinos from two nuclear power plants at a baseline of about 53 km. JUNO aims for an unprecedented energy resolution of 3% at 1 MeV for the central detector, with which the mass ordering can be measured with 3 - 4 $\sigma$ significance within six years of operation. Most neutrino oscillation parameters in the solar and atmospheric sectors can also be measured with an accuracy of 1% or better. Furthermore, being the largest liquid scintillator detector of its kind, JUNO will monitor the neutrino sky continuously for contributing to neutrino and multi-messenger astronomy. JUNO' s design as well as the status of its construction will be presented, together with a short excursion into its rich R&D program.

[71]  arXiv:1912.02131 (cross-list from physics.flu-dyn) [pdf, other]

Title: Linearly forced fluid flow on a rotating sphere

Authors: Rohit Supekar, Vili Heinonen, Keaton J. Burns, Jörn Dunkel

Comments: 12 pages, 5 figures

Subjects: Fluid Dynamics (physics.flu-dyn); Earth and Planetary Astrophysics (astro-ph.EP); Soft Condensed Matter (cond-mat.soft)

Motivated in part by the complex flow patterns observed in planetary atmospheres, we investigate generalized Navier-Stokes (GNS) equations that couple nonlinear advection with a generic linear instability. This analytically tractable minimal model for fluid flows driven by internal active stresses has recently been shown to permit exact solutions on a stationary 2D sphere. Here, we extend the analysis to linearly driven flows on rotating spheres, as relevant to quasi-2D atmospheres. We derive exact solutions of the GNS equations corresponding to time-independent zonal jets and superposed westward-propagating Rossby waves. Direct numerical simulations with large rotation rates obtain statistically stationary states close to these exact solutions. The measured phase speeds of waves in the GNS simulations agree with analytical predictions for Rossby waves.

Replacements for Thu, 5 Dec 19

[72]  arXiv:1412.5592 (replaced) [pdf, ps, other]

Title: Our Supermassive Black Hole Rivaled the Sun in the Ancient X-ray Sky

Authors: Pau Amaro-Seoane, Xian Chen

Comments: Minor changes, accepted for publication

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

[73]  arXiv:1706.05664 (replaced) [pdf, other]

Title: High-mass star formation in Orion possibly triggered by cloud-cloud collision III, NGC2068 and NGC2071

Authors: Shinji Fujita, Daichi Tsutsumi, Akio Ohama, Asao Habe, Nirmit Sakre, Kazuki Okawa, Mikito Kohno, Yusuke Hattori, Atsushi Nishimura, Kazufumi Torii, Hidetoshi Sano, Kengo Tachihara, Kimihiro Kimura, Hideo Ogawa, Yasuo Fukui

Comments: 20 peges, 7 figures

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

[74]  arXiv:1803.05390 (replaced) [pdf, other]

Title: Computational Techniques for the Analysis of Small Signals in High-Statistics Neutrino Oscillation Experiments

Authors: IceCube Collaboration: M. G. Aartsen, M. Ackermann, J. Adams, J. A. Aguilar, M. Ahlers, M. Ahrens, I. Al Samarai, D. Altmann, K. Andeen, T. Anderson, I. Ansseau, G. Anton, C. Argüelles, T. C. Arlen, J. Auffenberg, S. Axani, H. Bagherpour, X. Bai, A. Balagopal V., J. P. Barron, I. Bartos, S. W. Barwick, V. Baum, R. Bay, J. J. Beatty, J. Becker Tjus, K.-H. Becker, S. BenZvi, D. Berley, E. Bernardini, D. Z. Besson, G. Binder, D. Bindig, E. Blaufuss, S. Blot, C. Bohm, M. Bohmer, M. Börner, F. Bos, S. Böser, O. Botner, E. Bourbeau, J. Bourbeau, F. Bradascio, J. Braun, M. Brenzke, H.-P. Bretz, S. Bron, J. Brostean-Kaiser, A. Burgman, R. S. Busse, T. Carver, E. Cheung, D. Chirkin, A. Christov, K. Clark, L. Classen, G. H. Collin, J. M. Conrad, P. Coppin, P. Correa, D. F. Cowen, R. Cross, et al. (308 additional authors not shown)

Subjects: Data Analysis, Statistics and Probability (physics.data-an); Instrumentation and Methods for Astrophysics (astro-ph.IM); High Energy Physics - Experiment (hep-ex)

[75]  arXiv:1807.06205 (replaced) [pdf, other]

Title: Planck 2018 results. I. Overview and the cosmological legacy of Planck

Authors: Planck Collaboration: Y. Akrami, F. Arroja, M. Ashdown, J. Aumont, C. Baccigalupi, M. Ballardini, A. J. Banday, R. B. Barreiro, N. Bartolo, S. Basak, R. Battye, K. Benabed, J.-P. Bernard, M. Bersanelli, P. Bielewicz, J. J. Bock, J. R. Bond, J. Borrill, F. R. Bouchet, F. Boulanger, M. Bucher, C. Burigana, R. C. Butler, E. Calabrese, J.-F. Cardoso, J. Carron, B. Casaponsa, A. Challinor, H. C. Chiang, L. P. L. Colombo, C. Combet, D. Contreras, B. P. Crill, F. Cuttaia, P. de Bernardis, G. de Zotti, J. Delabrouille, J.-M. Delouis, F.-X. Désert, E. Di Valentino, C. Dickinson, J. M. Diego, S. Donzelli, O. Doré, M. Douspis, A. Ducout, X. Dupac, G. Efstathiou, F. Elsner, T. A. Enßlin, H. K. Eriksen, E. Falgarone, Y. Fantaye, J. Fergusson, R. Fernandez-Cobos, F. Finelli, F. Forastieri, et al. (133 additional authors not shown)

Comments: 61 pages, 40 figures, matches version accepted by A&A

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

[76]  arXiv:1901.00510 (replaced) [pdf, ps, other]

Title: Accretion of Small Satellites and Gas Inflows in a Disc Galaxy

Authors: F.G. Ramón-Fox, Hector Aceves

Comments: Accepted for publication in MNRAS

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

[77]  arXiv:1901.00869 (replaced) [pdf, other]

Title: Gravitational Wave Denoising of Binary Black Hole Mergers with Deep Learning

Authors: Wei Wei, E. A. Huerta

Comments: 26 pages, 10 figures. v2: new results for denoising and deglitching included, as well as denoising of spin-precessing binary black hole signals embedded in real advanced LIGO data. Accepted to Physics Letters B

Journal-ref: Physics Letters B 800 (2020) 135081

Subjects: General Relativity and Quantum Cosmology (gr-qc); Instrumentation and Methods for Astrophysics (astro-ph.IM); Data Analysis, Statistics and Probability (physics.data-an)

[78]  arXiv:1901.01095 (replaced) [pdf, other]

Title: SEAGLE--II: Constraints on feedback models in galaxy formation from massive early type strong lens galaxies

Authors: Sampath Mukherjee, Leon V. E. Koopmans, R. Benton Metcalf, Crescenzo Tortora, Matthieu Schaller, Joop Schaye, Giorgos Vernardos, Fabio Bellagamba

Comments: re-submitted to MNRAS, bug fixed, conclusions unchanged, added appendices, 23 pages, 10 Figures, 6 Tables

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

[79]  arXiv:1901.06384 (replaced) [pdf, other]

Title: SuperNNova: an open-source framework for Bayesian, Neural Network based supernova classification

Authors: Anais Möller, Thibault de Boissière

Comments: accepted version MNRAS December 2019

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

[80]  arXiv:1904.00409 (replaced) [pdf, other]

Title: Giant radio galaxies in the LOFAR Two-metre Sky Survey-I

Authors: P. Dabhade, H. J. A. Rottgering, J. Bagchi, T. W. Shimwell, M. J. Hardcastle, S. Sankhyayan, R. Morganti, M. Jamrozy, A. Shulevski, K. J. Duncan

Comments: Accepted for publication in Astronomy & Astrophysics

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

[81]  arXiv:1904.09476 (replaced) [pdf, other]

Title: A statistical method to detect non-stationarities of gamma-ray burst jets

Authors: Andor Budai, Peter Raffai, Balint Borgulya, Brian Albert Dawes, Gabor Szeifert, Vince Varga

Comments: 9 pages, 3 figures, published in MNRAS

Journal-ref: MNRAS 491 (2020) 1391-1397

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

[82]  arXiv:1904.10857 (replaced) [pdf, ps, other]

Title: Extracting the Global Signal from 21-cm Fluctuations: the Multi-Tracer Approach

Authors: Anastasia Fialkov (Sussex University), Rennan Barkana (Tel Aviv University), Matt Jarvis (Oxford)

Comments: 14 pages, 11 figures, accepted to MNRAS

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

[83]  arXiv:1905.05794 (replaced) [pdf, other]

Title: Evidence of Systematic Errors in $Spitzer$ Microlens Parallax Measurements

Authors: Naoki Koshimoto, David Bennett

Comments: 51 pages, 13 figures, 9 tables, submitted to AJ, significantly revised from v1 after the first review. (especially section 7.1 of "correlation between systematic errors and event's characteristics")

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

[84]  arXiv:1906.04429 (replaced) [pdf, other]

Title: A Search for a Contribution from Axion-Like Particles to the X-Ray Diffuse Background Utilizing the Earth's Magnetic Field

Authors: Ryo Yamamoto, Noriko Y. Yamasaki, Kazuhisa Mitsuda, Masahiro Takada

Comments: 13 pages, 4 figures, Prepared for submission to JCAP

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

[85]  arXiv:1906.08907 (replaced) [pdf, ps, other]

Title: A New Strategy for Estimating Photometric Redshifts of Quasars

Authors: Yanxia Zhang, Jingyi Zhang, Xin Jin, Yongheng Zhao

Comments: 16 pages, 7 figures, 6 tables, accepted by Research in Astronomy and Astrophysics (RAA)

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

[86]  arXiv:1907.06293 (replaced) [pdf, other]

Title: Cosmology with galaxy-galaxy lensing on non-perturbative scales: Emulation method and application to BOSS LOWZ

Authors: Benjamin D. Wibking, David H. Weinberg, Andrés N. Salcedo, Hao-Yi Wu, Sukhdeep Singh, Sergio Rodríguez-Torres, Lehman H. Garrison, Daniel J. Eisenstein

Comments: Updated to match accepted version

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

[87]  arXiv:1908.00046 (replaced) [pdf, other]

Title: Further evidence for a population of dark-matter-deficient dwarf galaxies

Authors: Qi Guo, Huijie Hu, Zheng Zheng, Shihong Liao, Wei Du, Shude Mao, Linhua Jiang, Jing Wang, Yingjie Peng, Liang Gao, Jie Wang, Hong Wu

Comments: Published in Nature Astronomy on 25 November 2019, 27 pages including appendix, 7 figures

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

[88]  arXiv:1908.00547 (replaced) [pdf, other]

Title: The buildup of strongly barred galaxies in the TNG100 simulation

Authors: Yetli Rosas-Guevara, Silvia Bonoli, Massimo Dotti, Tommaso Zana, Dylan Nelson, Annalisa Pillepich, Luis C. Ho, David Izquierdo-Villalba, Lars Hernquist, Ruediger Pakmor

Comments: 18 pages, 15 figures, and 1 table. Accepted in MNRAS

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

[89]  arXiv:1908.00747 (replaced) [pdf, other]

Title: Impact of substructure on local dark matter searches

Authors: Alejandro Ibarra, Bradley J. Kavanagh, Andreas Rappelt

Comments: 34 pages, 14 figures. v2: Matches version published in JCAP

Journal-ref: JCAP 12 (2019) 013

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

[90]  arXiv:1908.01781 (replaced) [pdf, other]

Title: Chandra Spectral and Timing Analysis of Sgr A*'s Brightest X-ray Flares

Authors: Daryl Haggard (McGill/MSI), Melania Nynka (MIT Kavli/McGill/MSI), Brayden Mon (McGill/MSI), Noelia de la Cruz Hernandez (McGill/MSI), Michael Nowak (Wash U), Craig Heinke (U Alberta), Joseph Neilsen (Villanova), Jason Dexter (Max-Planck/JILA/U Colorado), P. Chris Fragile (Charleston), Fred Baganoff (MIT Kavli), Geoffrey C. Bower (ASIAA), Lia R. Corrales (U Michigan), Francesco Coti Zelati (CSIC/IEEC), Nathalie Degenaar (U Amsterdam), Sera Markoff (U Amsterdam/GRAPPA), Mark R. Morris (UCLA), Gabriele Ponti (INAF-OA-Brera/Max-Planck), Nanda Rea (CSIC/IEEC), Joern Wilms (U Erlangen-Nuremberg), Farhad Yusef-Zadeh (Northwestern U/CIERA)

Comments: Updated to match published version; 19 pages, 7 figures, 3 tables

Journal-ref: The Astrophysical Journal, Volume 886, Issue 2, article id. 96, 14 pp. (2019)

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

[91]  arXiv:1909.05572 (replaced) [pdf, other]

Title: Current and future applications of Reverberation-mapped quasars in Cosmology

Authors: Swayamtrupta Panda, Mary Loli Martínez-Aldama, Michal Zajaček (on behalf of the LSST AGN Science Collaboration)

Comments: 26 pages, 10 figures, accepted in Frontiers in Astronomy and Space Sciences (section: Quasars in Cosmology)

Journal-ref: https://www.frontiersin.org/articles/10.3389/fspas.2019.00075/abstract

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

[92]  arXiv:1909.07560 (replaced) [pdf, other]

Title: The composition of Mars

Authors: Takashi Yoshizaki (1), William F. McDonough (1, 2, 3) ((1) Department of Earth Science, Tohoku University, Japan, (2) Department of Geology, University of Maryland, College Park, USA, (3) Research Center of Neutrino Sciences, Tohoku University, Japan)

Comments: 80 pages, 30 figures

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

[93]  arXiv:1909.07999 (replaced) [pdf, other]

Title: Origins of Type Ibn SNe 2006jc/2015G in interacting binaries and implications for pre-SN eruptions

Authors: Ning-Chen Sun, Jusytn R. Maund, Ryosuke Hirai, Paul A. Crowther, Philipp Podsiadlowski

Comments: 22 pages, 18 figures, accepted for publication in MNRAS

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

[94]  arXiv:1909.09475 (replaced) [pdf, other]

Title: Axion Quark Nuggets and how a Global Network can discover them

Authors: Dmitry Budker, Victor V. Flambaum, Xunyu Liang, Ariel Zhitnitsky

Comments: New section on the broadband detection strategy and the annual and daily modulation of the axion flux

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

[95]  arXiv:1909.11545 (replaced) [pdf, other]

Title: Dark Fermions and Spontaneous $CP$ violation in $SU(2)$-axion Inflation

Authors: Azadeh Maleknejad

Comments: 58 pages, 21 figures, V2: minor corrections and references added

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)

[96]  arXiv:1909.12630 (replaced) [pdf, other]

Title: White dwarfs as a probe of dark energy

Authors: Sviatoslav Smerechynskyi, Maksym Tsizh, Bohdan Novosyadlyj

Comments: 9 pages, 6 figures; minor changes; accepted for publication in Phys. Rev. D

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

[97]  arXiv:1910.01377 (replaced) [pdf, ps, other]

Title: Jets in the soft state in Cyg X-3 caused by advection of the donor magnetic field and unification with low-mass X-ray binaries

Authors: Xinwu Cao, Andrzej A. Zdziarski

Comments: MNRAS, in press

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

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

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

Authors: Lian-Bao Jia

Comments: 11 pages, 7 figures, with self-interactions re-estimated, and discussions improved

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

[99]  arXiv:1910.06976 (replaced) [pdf, other]

Title: Stellar winds pump the heart of the Milky Way

Authors: Diego Calderón, Jorge Cuadra, Marc Schartmann, Andreas Burkert, Christopher M. P. Russell

Comments: 6 pages and 5 figures. Accepted for publication in ApJL

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

[100]  arXiv:1910.11246 (replaced) [pdf, other]

Title: Implications of the search for optical counterparts during the first six months of the Advanced LIGO's and Advanced Virgo's third observing run: possible limits on the ejecta mass and binary properties

Authors: Michael W. Coughlin, Tim Dietrich, Sarah Antier, Mattia Bulla, Francois Foucart, Kenta Hotokezaka, Geert Raaijmakers, Tanja Hinderer, Samaya Nissanke

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

[101]  arXiv:1911.03964 (replaced) [pdf, other]

Title: Forecasts on Primordial non-Gaussianity from 21 cm Intensity Mapping experiments

Authors: Dionysios Karagiannis, Anže Slosar, Michele Liguori

Comments: 24 pages, 4 figures, minor corrections and references updated. Version submitted to JCAP

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

[102]  arXiv:1911.05394 (replaced) [pdf, other]

Title: Phase-space structure of cold dark matter halos inside splashback: multi-stream flows and self-similar solution

Authors: Hiromu Sugiura, Takahiro Nishimichi, Yann Rasera, Atsushi Taruya

Comments: 18 pages, 14 figures

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

[103]  arXiv:1911.08640 (replaced) [pdf, other]

Title: Differences in radio emission from similar M dwarfs in the binary system Ross 867-8

Authors: L. H. Quiroga-Nuñez, H. T. Intema, J. R. Callingham, J. Villadsen, H. J. van Langevelde, P. Jagannathan, T. W. Shimwell, E. P. Boven

Comments: Accepted for publication in A&A. Language edition included

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

[104]  arXiv:1911.10542 (replaced) [pdf, other]

Title: The unity of dark matter and dark energy in a curvaton scenario

Authors: Lei-Hua Liu, Wu-Long Xu

Comments: 25 pages, 3 figures, some typos are corrected

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

[105]  arXiv:1911.11513 (replaced) [pdf, other]

Title: Reheating in $R^2$ Palatini inflationary models

Authors: Ioannis D. Gialamas, A. B. Lahanas

Comments: 34 pages, 12 figures, pdflatex, references added, typos corrected

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

[106]  arXiv:1912.00441 (replaced) [pdf, other]

Title: Cluster formation induced by a cloud--cloud collision in [DBS2003]179

Authors: Sho Kuwahara, Kazufumi Torii, Norikazu Mizuno, Shinji Fujita, Mikito Kohno, Yasuo Fukui

Comments: 32 pages, 16 figures

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

[107]  arXiv:1912.01029 (replaced) [pdf, other]

Title: GS 2000+25: The Least Luminous Black Hole X-ray Binary

Authors: J. Rodriguez, R. Urquhart, R. M. Plotkin, T. Panurach, L. Chomiuk, J. Strader, J. C. A. Miller-Jones, E. Gallo, G. R. Sivakoff

Comments: 7 pages, 2 figures, accepted for publication in ApJ

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

[108]  arXiv:1912.01102 (replaced) [pdf, ps, other]

Title: Magnetic OB[A] Stars with TESS: probing their Evolutionary and Rotational properties -- The MOBSTER Collaboration

Authors: A. David-Uraz (1), C. Neiner (2), J. Sikora (3), J. Barron (4 and 5), D. M. Bowman (6), P. Cerrahoğlu (1), D. H. Cohen (7), C. Erba (1), V. Khalack (8), O. Kobzar (8), O. Kochukhov (9), H. Pablo (10), V. Petit (1), M. E. Shultz (1), A. ud-Doula (11), G. A. Wade (5), the MOBSTER Collaboration ((1) Department of Physics and Astronomy, University of Delaware, (2) LESIA, Paris Observatory, PSL University, CNRS, Sorbonne University, Université de Paris, Meudon, France, (3) Physics and Astronomy Department, Bishop's University, Sherbrooke, Canada, (4) Department of Physics, Engineering Physics & Astronomy, Queen's University, Kingston, ON, Canada, (5) Department of Physics and Space Science, Royal Military College of Canada, Kingston, ON, (6) Institute of Astronomy, KU Leuven, Belgium, (7) Department of Physics and Astronomy, Swarthmore College, Swarthmore, PA, (8) Département de Physique et d'Astronomie, Université de Moncton, Moncton, Canada, (9) Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden, (10) American Association of Variable Star Observers (AAVSO), Cambridge, MA, USA, (11) Penn State Scranton, Dunmore, PA, USA)

Comments: 4 pages, Conference proceedings: "Stars and their variability observed from space", Vienna, Austria, 2019

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

[109]  arXiv:1912.01186 (replaced) [pdf, ps, other]

Title: LBT/PEPSI Spectropolarimetry of a Magnetic Morphology Shift in Old Solar-type Stars

Authors: Travis S. Metcalfe, Oleg Kochukhov, Ilya V. Ilyin, Klaus G. Strassmeier, Diego Godoy-Rivera, Marc H. Pinsonneault

Comments: 7 pages, 3 figures, 2 tables, ApJ Letters (accepted)

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

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