RAS_WEB (Page 2,756)

Non-Standard Primordial Clocks from Dynamical Mass in Alternative to Inflation Scenarios. (arXiv:2007.09677v1 [hep-th]) <a href="http://arxiv.org/find/hep-th/1/au:+Wang_Y/0/1/0/all/0/1">Yi Wang</a>, <a href="http://arxiv.org/find/hep-th/1/au:+Wang_Z/0/1/0/all/0/1">Zun Wang</a>, <a href="http://arxiv.org/find/hep-th/1/au:+Zhu_Y/0/1/0/all/0/1">Yuhang Zhu</a> In the primordial universe, oscillations of heavy fields can be considered as standard clocks to measure the expansion or contraction history of the universe. Those standard clocks provide a model-independent way of distinguishing inflation and alternative scenarios. However, the mass of the heavy fields may not be a constant mass, but rather mass dynamically generated by non-minimal coupling to the Ricci scalar, or self-interactions. In the case of dynamically generated mass, the mass of the heavy field is generically of order Hubble, andRead More →

Confronting GW190814 with hyperonization in dense matter and hypernuclear compact stars. (arXiv:2007.09683v1 [astro-ph.HE]) <a href="http://arxiv.org/find/astro-ph/1/au:+Sedrakian_A/0/1/0/all/0/1">Armen Sedrakian</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Weber_F/0/1/0/all/0/1">Fridolin Weber</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+LI_J/0/1/0/all/0/1">Jia-Jie LI</a> We examine the possibility that the light companion in the highly asymmetric binary compact object coalescence event GW190814 is a hypernuclear star. We use density functional theory with functionals that have been tuned to the properties of $Lambda$ hypernuclei as well as astrophysical constraints placed by the masses of the most massive millisecond pulsars, the mass-radius range inferred from the NICER experiment, and the binary neutron star merger event GW170817. We compute general-relativistic static and maximally rotating Keplerian configurations of purely nucleonic andRead More →

The Origin of Matter at the Base of Relativistic Jets in Active Galactic Nuclei. (arXiv:2007.09717v1 [astro-ph.HE]) <a href="http://arxiv.org/find/astro-ph/1/au:+Romero_G/0/1/0/all/0/1">Gustavo E. Romero</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gutierrez_E/0/1/0/all/0/1">Eduardo M. Guti&#xe9;rrez</a> The generation of relativistic jets in active sources such as blazars is a complex problem with many aspects, most of them still not fully understood. Relativistic jets are likely produced by the accretion of matter and magnetic fields onto spinning black holes. Ergospheric dragging effects launch a Poynting-dominated outflow in the polar directions of these systems. Observations with very high resolution of the jet in the nearby radio galaxy M87 and evidence of extremely fast variability in the non-thermal radiation ofRead More →

White Paper Towards a Fuller Understanding of Icy Satellite Seafloors, Interiors, and Habitability. (arXiv:2007.09728v1 [astro-ph.IM]) <a href="http://arxiv.org/find/astro-ph/1/au:+Byrne_P/0/1/0/all/0/1">Paul K. Byrne</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dombard_A/0/1/0/all/0/1">Andrew J. Dombard</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Elder_C/0/1/0/all/0/1">Catherine M. Elder</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hauck_S/0/1/0/all/0/1">Steven A. Hauck, II</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Daswani_M/0/1/0/all/0/1">Mohit Melwani Daswani</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Regensburger_P/0/1/0/all/0/1">Paul V. Regensburger</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Vance_S/0/1/0/all/0/1">Steven D. Vance</a> Icy satellites represent compelling astrobiological targets, but their rocky interiors must be better characterized. Fundamental research programs and thematic workshops promoting ocean world interdisciplinarity are key. Future missions to icy satellites should explicitly include objectives to characterize interfaces between rock and water or high-pressure ices. Icy satellites represent compelling astrobiological targets, but their rocky interiors must be better characterized. Fundamental researchRead More →

White Paper on the Case for Landed Mercury Science. (arXiv:2007.09735v1 [astro-ph.IM]) <a href="http://arxiv.org/find/astro-ph/1/au:+Byrne_P/0/1/0/all/0/1">Paul K. Byrne</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Blewett_D/0/1/0/all/0/1">David T. Blewett</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Chabot_N/0/1/0/all/0/1">Nancy L. Chabot</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hauck_S/0/1/0/all/0/1">Steven A. Hauck, II</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mazarico_E/0/1/0/all/0/1">Erwan Mazarico</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kaaden_K/0/1/0/all/0/1">Kathleen E. Vander Kaaden</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Vervack_R/0/1/0/all/0/1">Ronald J. Vervack</a> We advocate for establishing key scientific priorities for the future of Mercury exploration, including the development of specific science goals for a landed mission. We support the Mercury science community in fostering closer collaboration with ongoing and planned exoplanet investigations. The continued exploration of Mercury should be conceived as a multi-mission, multi-generational effort, and that the landed exploration of Mercury be a high scientific priorityRead More →

Anisotropic Neutron Stars Modelling: Constraints in Krori-Barua Spacetime. (arXiv:2007.09797v1 [gr-qc]) <a href="http://arxiv.org/find/gr-qc/1/au:+Roupas_Z/0/1/0/all/0/1">Zacharias Roupas</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Nashed_G/0/1/0/all/0/1">Gamal G. L. Nashed</a> Dense nuclear matter is expected to be anisotropic due to effects such as solidification, superfluidity, strong magnetic fields, hyperons, pion-condesation. Therefore an anisotropic pulsars core seems more realistic than an ideally isotropic one. We model anisotropic neutron stars working in the Krori-Barua (KB) ansatz without preassuming an equation of state. We show that the physics of general KB solutions is encapsulated in the compactness. Imposing physical and stability requirements yields a maximum allowed compactness $2GM/Rc^2 < 0.71$ for a KB-spacetime. We further input observational data from numerousRead More →

Adiabatic mass loss in binary stars. III. From the base of the red giant branch to the tip of asymptotic giant branch. (arXiv:2007.09848v1 [astro-ph.SR]) <a href="http://arxiv.org/find/astro-ph/1/au:+Ge_H/0/1/0/all/0/1">Hongwei Ge</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Webbink_R/0/1/0/all/0/1">Ronald F Webbink</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Chen_X/0/1/0/all/0/1">Xuefei Chen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Han_Z/0/1/0/all/0/1">Zhanwen Han</a> The distinguishing feature of the evolution of close binary stars is the role played by the mass exchange between the component stars. Whether the mass transfer is dynamically stable is one of the essential questions in binary evolution. In the limit of extremely rapid mass transfer, the response of a donor star in an interacting binary becomes asymptotically one of adiabatic expansion. We use the adiabatic mass lossRead More →

Physical properties and evolution of (Sub-)millimeter selected galaxies in the galaxy formation simulation Shark. (arXiv:2007.09853v1 [astro-ph.GA]) <a href="http://arxiv.org/find/astro-ph/1/au:+Lagos_C/0/1/0/all/0/1">Claudia del P. Lagos</a> (1,2,3), <a href="http://arxiv.org/find/astro-ph/1/au:+Cunha_E/0/1/0/all/0/1">Elisabete da Cunha</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Robotham_A/0/1/0/all/0/1">Aaron S.G. Robotham</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Obreschkow_D/0/1/0/all/0/1">Danail Obreschkow</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Valentino_F/0/1/0/all/0/1">Francesco Valentino</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fujimoto_S/0/1/0/all/0/1">Seiji Fujimoto</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Magdis_G/0/1/0/all/0/1">Georgios E. Magdis</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tobar_R/0/1/0/all/0/1">Rodrigo Tobar</a> (1: ICRAR/UWA, 2: ASTRO 3D, 3: Cosmic Dawn Center) We thoroughly explore the properties of (sub)-millimeter (mm) selected galaxies (SMGs) in the Shark semi-analytic model of galaxy formation. Compared to observations, the predicted number counts at wavelengths (lambda) 0.6-2mm and redshift distributions at 0.1-2mm, agree well. At the bright end (>1mJy), Shark galaxies are a mix of mergers andRead More →

Stability of relativistic stars with scalar hairs. (arXiv:2007.09864v1 [gr-qc]) <a href="http://arxiv.org/find/gr-qc/1/au:+Kase_R/0/1/0/all/0/1">Ryotaro Kase</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Kimura_R/0/1/0/all/0/1">Rampei Kimura</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Sato_S/0/1/0/all/0/1">Seiga Sato</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Tsujikawa_S/0/1/0/all/0/1">Shinji Tsujikawa</a> We study the stability of relativistic stars in scalar-tensor theories with a nonminimal coupling of the form $F(phi)R$, where $F$ depends on a scalar field $phi$ and $R$ is the Ricci scalar. On a spherically symmetric and static background, we incorporate a perfect fluid minimally coupled to gravity as a form of the Schutz-Sorkin action. The odd-parity perturbation for the multipoles $l geq 2$ is ghost-free under the condition $F(phi)>0$, with the speed of gravity equivalent to that of light. For even-parity perturbations withRead More →

ALMA Deep Field in SSA22: A near-infrared-dark submillimeter galaxy at z=4.0. (arXiv:2007.09887v1 [astro-ph.GA]) <a href="http://arxiv.org/find/astro-ph/1/au:+Umehata_H/0/1/0/all/0/1">Hideki Umehata</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Smail_I/0/1/0/all/0/1">Ian Smail</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Swinbank_A/0/1/0/all/0/1">A.M. Swinbank</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kohno_K/0/1/0/all/0/1">Kotaro Kohno</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tamura_Y/0/1/0/all/0/1">Yoichi Tamura</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wang_T/0/1/0/all/0/1">Tao Wang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ao_Y/0/1/0/all/0/1">Yiping Ao</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hatsukade_B/0/1/0/all/0/1">Bunyo Hatsukade</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kubo_M/0/1/0/all/0/1">Mariko Kubo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Nakanishi_K/0/1/0/all/0/1">Kouchiro Nakanishi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hayatsu_N/0/1/0/all/0/1">Natsuki N. Hayatsu</a> Deep surveys with Atacama Large Millimeter Array (ALMA) have uncovered a population of dusty star-forming galaxies which are faint or even undetected at optical to near-infrared wavelengths. Their faintness at short wavelengths makes detailed characterization of the population challenging. Here we present a spectroscopic redshift identification and characterization of one of such near-infrared-dark galaxy discovered by an ALMARead More →

Does the HR 6819 triple system contain a dormant black hole? Not necessarily. (arXiv:2007.08522v1 [astro-ph.SR]) <a href="http://arxiv.org/find/astro-ph/1/au:+Mazeh_T/0/1/0/all/0/1">Tsevi Mazeh</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Faigler_S/0/1/0/all/0/1">Simchon Faigler</a> A recent paper by Rivinius et al. proposed that HR 6819 is a triple system, with a distant Be star and a binary of 40-day orbit, composed of a B3 III giant and a dormant black hole (BH). We suggest that the evidence for this model is not conclusive. In an alternative model, the companion of the giant is by itself a short-period binary in, say, a $sim$$4$-day orbit, consisting, for example, of two A0 stars. Each of the two A0 stars should contributeRead More →

The Discovery of a Hidden Broad Line AGN in a Bulgeless Galaxy: Keck NIR Spectroscopic Observations of SDSS J085153.64+392611.76. (arXiv:2007.08525v1 [astro-ph.GA]) <a href="http://arxiv.org/find/astro-ph/1/au:+Bohn_T/0/1/0/all/0/1">Thomas Bohn</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Canalizo_G/0/1/0/all/0/1">Gabriela Canalizo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Satyapal_S/0/1/0/all/0/1">Shobita Satyapal</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pfeifle_R/0/1/0/all/0/1">Ryan W. Pfeifle</a> We report the discovery of a buried, active supermassive black hole in SDSS J085153.64+392611.76, a bulgeless Seyfert 2 (Sy2) galaxy. Keck near-infrared observations reveal a hidden broad line region, allowing for the rare case where strong constraints can be placed on both the black hole mass and bulge component. Using virial mass estimators, we obtain a black hole mass of log($M_{rm{BH}}/M_{odot}$) = $6.78 pm 0.50$. This is one of the onlyRead More →

Hidden AGN in dwarf galaxies revealed by MaNGA: light echoes, off-nuclear wanderers, and a new broad-line AGN. (arXiv:2007.08527v1 [astro-ph.GA]) <a href="http://arxiv.org/find/astro-ph/1/au:+Mezcua_M/0/1/0/all/0/1">M. Mezcua</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sanchez_H/0/1/0/all/0/1">H. Dom&#xed;nguez S&#xe1;nchez</a> Active galactic nuclei (AGN) in dwarf galaxies could possibly host the relics of those early Universe seed black holes that did not grow into supermassive black holes. Using MaNGA integral field unit (IFU) spectroscopy we have found a sample of 37 dwarf galaxies that show AGN ionisation signatures in spatially-resolved emission line diagnostic diagrams. The AGN signatures are largely missed by integrated emission line diagnostics for 23 of them. The bolometric luminosity of these 23 new AGN candidates isRead More →

FIREBall-2: The Faint Intergalactic Medium Redshifted Emission Balloon Telescope. (arXiv:2007.08528v1 [astro-ph.IM]) <a href="http://arxiv.org/find/astro-ph/1/au:+Hamden_E/0/1/0/all/0/1">Erika Hamden</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Martin_D/0/1/0/all/0/1">D. Christopher Martin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Milliard_B/0/1/0/all/0/1">Bruno Milliard</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Schiminovich_D/0/1/0/all/0/1">David Schiminovich</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Nikzad_S/0/1/0/all/0/1">Shouleh Nikzad</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Evrard_J/0/1/0/all/0/1">Jean Evrard</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kyne_G/0/1/0/all/0/1">Gillian Kyne</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Grange_R/0/1/0/all/0/1">Robert Grange</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Montel_J/0/1/0/all/0/1">Johan Montel</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pirot_E/0/1/0/all/0/1">Etienne Pirot</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hoadley_K/0/1/0/all/0/1">Keri Hoadley</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+OSullivan_D/0/1/0/all/0/1">Donal O&#x27;Sullivan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Melso_N/0/1/0/all/0/1">Nicole Melso</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Picouet_V/0/1/0/all/0/1">Vincent Picouet</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Vibert_D/0/1/0/all/0/1">Didier Vibert</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Balard_P/0/1/0/all/0/1">Philippe Balard</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Blanchard_P/0/1/0/all/0/1">Patrick Blanchard</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Crabill_M/0/1/0/all/0/1">Marty Crabill</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pascal_S/0/1/0/all/0/1">Sandrine Pascal</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mirc_F/0/1/0/all/0/1">Frederi Mirc</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bray_N/0/1/0/all/0/1">Nicolas Bray</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Jewell_A/0/1/0/all/0/1">April Jewell</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bird_J/0/1/0/all/0/1">Julia Blue Bird</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zorilla_J/0/1/0/all/0/1">Jose Zorilla</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ong_H/0/1/0/all/0/1">Hwei Ru Ong</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Matuszewski_M/0/1/0/all/0/1">Mateusz Matuszewski</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lingner_N/0/1/0/all/0/1">Nicole Lingner</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Augustin_R/0/1/0/all/0/1">Ramona Augustin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Limon_M/0/1/0/all/0/1">Michele Limon</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gomes_A/0/1/0/all/0/1">Albert Gomes</a>, <aRead More →

In search of the weirdest galaxies in the Universe. (arXiv:2007.08530v1 [astro-ph.GA]) <a href="http://arxiv.org/find/astro-ph/1/au:+Formsma_J/0/1/0/all/0/1">Job Formsma</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Saifollahi_T/0/1/0/all/0/1">Teymoor Saifollahi</a> Weird galaxies are outliers that have either unknown or very uncommon features making them different from the normal sample. These galaxies are very interesting as they may provide new insights into current theories, or can be used to form new theories about processes in the Universe. Interesting outliers are often found by accident, but this will become increasingly more difficult with future big surveys generating an enormous amount of data. This gives the need for machine learning detection techniques to find the interesting weird objects. In this work,Read More →

Neutron Star-Black Hole Mergers from Gravitational Wave Captures. (arXiv:2007.08531v1 [astro-ph.HE]) <a href="http://arxiv.org/find/astro-ph/1/au:+Hoang_B/0/1/0/all/0/1">Bao-Minh Hoang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Naoz_S/0/1/0/all/0/1">Smadar Naoz</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kremer_K/0/1/0/all/0/1">Kyle Kremer</a> LIGO’s third observing run (O3) has reported several neutron star-black hole (NSBH) merger candidates. From a theoretical point of view, NSBH mergers have received less attention in the community than either binary black holes (BBHs), or binary neutron stars (BNSs). Here we examine single-single (sin-sin) gravitational wave (GW) captures in different types of star clusters — galactic nuclei (GN), globular clusters (GC), and young stellar clusters (YSC) — and compare the merger rates from this channel to other proposed merger channels in the literature. There areRead More →

The structure and characteristic scales of molecular clouds. (arXiv:2007.08533v1 [astro-ph.GA]) <a href="http://arxiv.org/find/astro-ph/1/au:+Dib_S/0/1/0/all/0/1">Sami Dib</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bontemps_S/0/1/0/all/0/1">Sylvain Bontemps</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Schneider_N/0/1/0/all/0/1">Nicola Schneider</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Elia_D/0/1/0/all/0/1">Davide Elia</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ossenkopf_Okada_V/0/1/0/all/0/1">Volker Ossenkopf-Okada</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Shadmehri_M/0/1/0/all/0/1">Mohsen Shadmehri</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Arzoumanian_D/0/1/0/all/0/1">Doris Arzoumanian</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Motte_F/0/1/0/all/0/1">Frederique Motte</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Heyer_M/0/1/0/all/0/1">Mark Heyer</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Nordlund_A/0/1/0/all/0/1">Ake Nordlund</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Robitaille_J/0/1/0/all/0/1">Jean-Francois Robitaille</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ladjelate_B/0/1/0/all/0/1">Bilal Ladjelate</a> The structure of molecular clouds (MCs) holds important clues on the physical processes that lead to their formation and subsequent evolution. While it is well established that turbulence imprints a self-similar structure to the clouds, other processes, such as gravity and stellar feedback, can break their scale-free nature. The break of self-similarity can manifest itself in the existence ofRead More →