RAS_WEB (Page 4,636)

Stellar Accelerations and the Galactic Gravitational Field. (arXiv:1812.07581v1 [astro-ph.GA]) <a href="http://arxiv.org/find/astro-ph/1/au:+Silverwood_H/0/1/0/all/0/1">Hamish Silverwood</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Easther_R/0/1/0/all/0/1">Richard Easther</a> Typical stars in the Milky Way galaxy have velocities of hundreds of kilometres per second and experience gravitational accelerations of $sim 10^{-10}$ m s$^{-2}$, resulting in velocity changes of a few centimetres per second over a decade. Measurements of these accelerations would permit direct tests of the applicability of Newtonian dynamics on kiloparsec length scales and could reveal significant small scale inhomogeneities within the galaxy, as well increasing the sensitivity of measurements of the overall mass distribution of the galaxy. Noting that a reasonable extrapolation of progress in exoplanet huntingRead More →

The Fornax 3D project: dust mix and gas properties in the center of early-type galaxy FCC 167. (arXiv:1812.07582v1 [astro-ph.GA]) <a href="http://arxiv.org/find/astro-ph/1/au:+Viaene_S/0/1/0/all/0/1">S. Viaene</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sarzi_M/0/1/0/all/0/1">M. Sarzi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zabel_N/0/1/0/all/0/1">N. Zabel</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Coccato_L/0/1/0/all/0/1">L. Coccato</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Corsini_E/0/1/0/all/0/1">E. M. Corsini</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Davis_T/0/1/0/all/0/1">T. A. Davis</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Vis_P/0/1/0/all/0/1">P. De Vis</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zeeuw_P/0/1/0/all/0/1">P. T. de Zeeuw</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Falcon_Barroso_J/0/1/0/all/0/1">J. Falc&#xf3;n-Barroso</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gadotti_D/0/1/0/all/0/1">D.A. Gadotti</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Iodice_E/0/1/0/all/0/1">E. Iodice</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lyubenova_M/0/1/0/all/0/1">M. Lyubenova</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+McDermid_R/0/1/0/all/0/1">R. McDermid</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Morelli_L/0/1/0/all/0/1">L. Morelli</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Nedelchev_B/0/1/0/all/0/1">B. Nedelchev</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pinna_F/0/1/0/all/0/1">F. Pinna</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Spriggs_T/0/1/0/all/0/1">T. W. Spriggs</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ven_G/0/1/0/all/0/1">G. van de Ven</a> Galaxies continuously reprocess their interstellar material. One can therefore expect changing dust grain properties in galaxies which have followed different evolutionary pathways. Determining theRead More →

The star-formation activity of IllustrisTNG galaxies: main sequence, UVJ diagram, quenched fractions, and systematics. (arXiv:1812.07584v1 [astro-ph.GA]) <a href="http://arxiv.org/find/astro-ph/1/au:+Donnari_M/0/1/0/all/0/1">Martina Donnari</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pillepich_A/0/1/0/all/0/1">Annalisa Pillepich</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Nelson_D/0/1/0/all/0/1">Dylan Nelson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Vogelsberger_M/0/1/0/all/0/1">Mark Vogelsberger</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Genel_S/0/1/0/all/0/1">Shy Genel</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Weinberger_R/0/1/0/all/0/1">Rainer Weinberger</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Marinacci_F/0/1/0/all/0/1">Federico Marinacci</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Springel_V/0/1/0/all/0/1">Volker Springel</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hernquist_L/0/1/0/all/0/1">Lars Hernquist</a> We select galaxies from the IllustrisTNG hydrodynamical simulations ($M_*>10^9~rm M_odot$ at $0le zle2$) and characterize the shapes and evolutions of their UVJ and star-formation rate — stellar mass (SFR-$M_*$) diagrams. We quantify the systematic uncertainties related to different criteria to classify star-forming vs. quiescent galaxies, different SFR estimates, and by accounting for the star formation measured within different physical apertures. The TNGRead More →

Cosmological beam dump: constraints on dark scalars mixed with the Higgs boson. (arXiv:1812.07585v1 [hep-ph]) <a href="http://arxiv.org/find/hep-ph/1/au:+Fradette_A/0/1/0/all/0/1">Anthony Fradette</a>, <a href="http://arxiv.org/find/hep-ph/1/au:+Pospelov_M/0/1/0/all/0/1">Maxim Pospelov</a>, <a href="http://arxiv.org/find/hep-ph/1/au:+Pradler_J/0/1/0/all/0/1">Josef Pradler</a>, <a href="http://arxiv.org/find/hep-ph/1/au:+Ritz_A/0/1/0/all/0/1">Adam Ritz</a> Precision cosmology provides a sensitive probe of extremely weakly coupled states due to thermal freeze-in production, with subsequent decays impacting physics during well-tested cosmological epochs. We explore the cosmological implications of the freeze-in production of a new scalar $S$ via the super-renormalizable Higgs portal. If the mass of $S$ is at or below the electroweak scale, peak freeze-in production occurs during the electroweak epoch. We improve the calculation of the freeze-in abundance by including all relevant QCD and electroweakRead More →

The early instability scenario: terrestrial planet formation during the giant planet instability, and the effect of collisional fragmentation. (arXiv:1812.07590v1 [astro-ph.EP]) <a href="http://arxiv.org/find/astro-ph/1/au:+Clement_M/0/1/0/all/0/1">Matthew S. Clement</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kaib_N/0/1/0/all/0/1">Nathan A. Kaib</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Raymond_S/0/1/0/all/0/1">Sean N. Raymond</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Chambers_J/0/1/0/all/0/1">John E. Chambers</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Walsh_K/0/1/0/all/0/1">Kevin J. Walsh</a> The solar system’s dynamical state can be explained by an orbital instability among the giant planets. A recent model has proposed that the giant planet instability happened during terrestrial planet formation. This scenario has been shown to match the inner solar system by stunting Mars’ growth and preventing planet formation in the asteroid belt. Here we present a large sample of new simulations of theRead More →

Polygram Stars: Resonant Tidal Excitation of Fundamental Oscillation Modes in Asynchronous Stellar Coalescence. (arXiv:1812.07594v1 [astro-ph.SR]) <a href="http://arxiv.org/find/astro-ph/1/au:+MacLeod_M/0/1/0/all/0/1">Morgan MacLeod</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Vick_M/0/1/0/all/0/1">Michelle Vick</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lai_D/0/1/0/all/0/1">Dong Lai</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Stone_J/0/1/0/all/0/1">James M. Stone</a> The prevalence of binary stars at close separations implies that many of these systems will interact or merge during the binary’s lifetime. This paper presents hydrodynamic simulations of the scenario of binary coalescence through unstable mass transfer, which drives the pair to closer separations. When the donor star does not rotate synchronously with respect to the orbit, dynamical tidal waves are excited in its envelope. We show that resonance crossings with high azimuthal-order $(msim3$ to $6$) fundamentalRead More →

Geometrical Constraints of Observing Very High Energy Earth-Skimming Neutrinos from Space. (arXiv:1812.07596v1 [astro-ph.IM]) <a href="http://arxiv.org/find/astro-ph/1/au:+Guepin_C/0/1/0/all/0/1">Claire Gu&#xe9;pin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sarazin_F/0/1/0/all/0/1">Fr&#xe9;d&#xe9;ric Sarazin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Krizmanic_J/0/1/0/all/0/1">John Krizmanic</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Loerincs_J/0/1/0/all/0/1">Jacqueline Loerincs</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Olinto_A/0/1/0/all/0/1">Angela Olinto</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Piccone_A/0/1/0/all/0/1">Ashley Piccone</a> The detection of very-high-energy (VHE) neutrinos ($E_nu gtrsim 10$ PeV) is a challenge that future generations of experiments are being designed and constructed to address. One promising method relies on using the Earth as a neutrino target for indirect detection of skimming tau neutrinos interacting within the Earth and producing tau leptons that are able to escape and decay in the atmosphere. The tau decay produces upward-moving Extensive Air Showers (EASs). A space-based orRead More →

Solution of the cosmological constant problem within holographic cosmology. (arXiv:1812.07597v1 [hep-th]) <a href="http://arxiv.org/find/hep-th/1/au:+Nastase_H/0/1/0/all/0/1">Horatiu Nastase</a> Within the holographic cosmology paradigm, specifically the model of McFadden and Skenderis, but more generally than that, the cosmological constant is found to naturally flow from a large value, to a small value, which can even be as low as the needed $sim 10^{-120}$ times the original, along with the dual RG flow. Within this context then, the cosmological constant problem is mapped to a simple quantum field theory property, even though the exact mechanism for it in gravity is still obscure. I consider several examples of gravity duals to explainRead More →

Exotic compact objects with soft hair. (arXiv:1812.07615v1 [gr-qc]) <a href="http://arxiv.org/find/gr-qc/1/au:+Raposo_G/0/1/0/all/0/1">Guilherme Raposo</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Pani_P/0/1/0/all/0/1">Paolo Pani</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Emparan_R/0/1/0/all/0/1">Roberto Emparan</a> Motivated by the lack of a general parametrization for exotic compact objects, we construct a class of perturbative solutions valid for small (but otherwise generic) multipolar deviations from a Schwarzschild metric in general relativity. We introduce two classes of exotic compact objects, with “soft” and “hard” hair, for which the curvature at the surface is respectively comparable to or much larger than that at the corresponding black-hole horizon. We extend the Hartle-Thorne formalism to relax the assumption of equatorial symmetry and to include deformations induced by multipole momentsRead More →

ALMA polarimetric studies of rotating jet/disk systems. (arXiv:1812.07618v1 [astro-ph.SR]) <a href="http://arxiv.org/find/astro-ph/1/au:+Bacciotti_F/0/1/0/all/0/1">F. Bacciotti</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Girart_J/0/1/0/all/0/1">J.M. Girart</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Padovani_M/0/1/0/all/0/1">M. Padovani</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Podio_L/0/1/0/all/0/1">L. Podio</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Paladino_R/0/1/0/all/0/1">R. Paladino</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Testi_L/0/1/0/all/0/1">L. Testi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bianchi_E/0/1/0/all/0/1">E. Bianchi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Galli_D/0/1/0/all/0/1">D. Galli</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Codella_C/0/1/0/all/0/1">C. Codella</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Coffey_D/0/1/0/all/0/1">D. Coffey</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Favre_C/0/1/0/all/0/1">C. Favre</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fedele_D/0/1/0/all/0/1">D. Fedele</a> We have recently obtained polarimetric data at mm wavelengths with ALMA for the young systems DG Tau and CW Tau, for which the rotation properties of jet and disk have been investigated in previous high angular resolution studies. The motivation was to test the models of magneto-centrifugal launch of jets via the determination of the magnetic configuration at the diskRead More →

Supernovae from blue supergiant progenitors: What a mess!. (arXiv:1812.07620v1 [astro-ph.SR]) <a href="http://arxiv.org/find/astro-ph/1/au:+Dessart_L/0/1/0/all/0/1">Luc Dessart</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hillier_D/0/1/0/all/0/1">D. John Hillier</a> Since the discovery of SN (supernova) 1987A, the number of Type II-peculiar SNe has grown, revealing a rich diversity in photometric and spectroscopic properties. In this study, using a single 15Msun low-metallicity progenitor that dies as a blue supergiant (BSG), we have generated explosions with a range of energies and 56Ni masses. We then performed the radiative transfer modeling with CMFGEN from 1d until 300d after explosion. Our models yield light curves that rise to optical maximum in ~100d, with a similar brightening rate, and with a peakRead More →

K2 Ultracool Dwarfs Survey. V. High superflare rates on rapidly rotating late-M dwarfs. (arXiv:1812.07631v1 [astro-ph.SR]) <a href="http://arxiv.org/find/astro-ph/1/au:+Paudel_R/0/1/0/all/0/1">Rishi R. Paudel</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gizis_J/0/1/0/all/0/1">John E. Gizis</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mullan_D/0/1/0/all/0/1">D. J. Mullan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Schmidt_S/0/1/0/all/0/1">Sarah J. Schmidt</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Burgasser_A/0/1/0/all/0/1">Adam J. Burgasser</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Williams_P/0/1/0/all/0/1">Peter K. G. Williams</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Youngblood_A/0/1/0/all/0/1">Allison Youngblood</a> We observed strong superflares (defined as flares with energy in excess of 10^33 erg) on three late-M dwarfs: 2MASS J08315742+2042213 (hereafter 2M0831+2042; M7 V), 2MASS J08371832+2050349 (hereafter 2M0837+2050; M8 V) and 2MASS J08312608+2244586 (hereafter 2M0831+2244; M9 V). 2M0831+2042 and 2M0837+2050 are members of the young (~700 Myr) open cluster Praesepe. The strong superflare on 2M0831+2042 has an equivalent duration (ED) of 13.7Read More →

(Self-)Magnetized Bose-Einstein Condensate stars. (arXiv:1812.07657v1 [astro-ph.HE]) <a href="http://arxiv.org/find/astro-ph/1/au:+Angulo_G/0/1/0/all/0/1">G. Quintero Angulo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Martinez_A/0/1/0/all/0/1">A. P&#xe9;rez Mart&#xed;nez</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Rojas_H/0/1/0/all/0/1">H. P&#xe9;rez Rojas</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Paret_D/0/1/0/all/0/1">D. Manreza Paret</a> We study magnetic field effects on the Equations of State (EoS) and the structure of Bose-Einstein Condensate (BEC) stars, i.e. a compact object composed by a gas of interacting spin one bosons formed up by the pairing of two neutrons. To include the magnetic field in the thermodynamic description, we suppose that particle-magnetic field and particle-particle interactions are independent. We consider two configurations for the magnetic field: one where it constant and externally fixed, and another where it is produced by the bosonsRead More →

HATS-54b-HATS-58Ab: five new transiting hot Jupiters including one with a possible temperate companion. (arXiv:1812.07668v1 [astro-ph.EP]) <a href="http://arxiv.org/find/astro-ph/1/au:+Espinoza_N/0/1/0/all/0/1">N&#xe9;stor Espinoza</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hartman_J/0/1/0/all/0/1">Joel D. Hartman</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bakos_G/0/1/0/all/0/1">Gaspar &#xc1;. Bakos</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Henning_T/0/1/0/all/0/1">Thomas Henning</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bayliss_D/0/1/0/all/0/1">Daniel Bayliss</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bento_J/0/1/0/all/0/1">Joao Bento</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bhatti_W/0/1/0/all/0/1">Waqas Bhatti</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Brahm_R/0/1/0/all/0/1">Rafael Brahm</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Csubry_Z/0/1/0/all/0/1">Zoltan Csubry</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Suc_V/0/1/0/all/0/1">Vincent Suc</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Jordan_A/0/1/0/all/0/1">Andr&#xe9;s Jord&#xe1;n</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mancini_L/0/1/0/all/0/1">Luigi Mancini</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tan_T/0/1/0/all/0/1">T. G. Tan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Penev_K/0/1/0/all/0/1">Kaloyan Penev</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Rabus_M/0/1/0/all/0/1">Markus Rabus</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sarkis_P/0/1/0/all/0/1">Paula Sarkis</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Val_Borro_M/0/1/0/all/0/1">Miguel de Val-Borro</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Durkan_S/0/1/0/all/0/1">Stephen Durkan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lazar_J/0/1/0/all/0/1">Josef Lazar</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Papp_I/0/1/0/all/0/1">Istvan Papp</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sari_P/0/1/0/all/0/1">Pal Sari</a> We report the discovery by the HATSouth project of 5 new transiting hot Jupiters (HATS-54b through HATS-58Ab). HATS-54b, HATS-55b and HATS-58Ab are prototypicalRead More →

De Sitter Swampland Bound in Dirac-Born-Infeld Inflation Model. (arXiv:1812.07670v1 [hep-th]) <a href="http://arxiv.org/find/hep-th/1/au:+Seo_M/0/1/0/all/0/1">Min-Seok Seo</a> We study the de Sitter (dS) swampland conjecture in Dirac-Born-Infeld (DBI) inflation model. We obtain the dS swampland bound for the relativistic regime using Bousso’s entropy bound argument and proper distance. It restricts $m_{rm Pl}nabla V/V$ by some positive constant depending on warping and the field range. In the specific case of the DBI model driven by the quadratic potential, the model dependent backreaction argument is interpreted as a natural bound for slow-roll parameter. This shows that quasi-dS spacetime in the DBI model is a result of tuning. We study the deRead More →

Unexpected Topology of the Temperature Fluctuations in the Cosmic Microwave Background. (arXiv:1812.07678v1 [astro-ph.CO]) <a href="http://arxiv.org/find/astro-ph/1/au:+Pranav_P/0/1/0/all/0/1">Pratyush Pranav</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Adler_R/0/1/0/all/0/1">Robert J. Adler</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Buchert_T/0/1/0/all/0/1">Thomas Buchert</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Edelsbrunner_H/0/1/0/all/0/1">Herbert Edelsbrunner</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Jones_B/0/1/0/all/0/1">Bernard J.T. Jones</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Schwartzman_A/0/1/0/all/0/1">Armin Schwartzman</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wagner_H/0/1/0/all/0/1">Hubert Wagner</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Weygaert_R/0/1/0/all/0/1">Rien van de Weygaert</a> We study the topology generated by the temperature fluctuations of the Cosmic Microwave Background (CMB) radiation, as quantified by the number of components and holes, formally given by the Betti numbers, in the growing excursion sets. We compare CMB maps observed by the Planck satellite with a thousand simulated maps generated according to the LCDM paradigm with Gaussian distributed fluctuations. The survey of theRead More →

Circumstellar dust distribution in systems with two planets in resonance. (arXiv:1812.07698v1 [astro-ph.EP]) <a href="http://arxiv.org/find/astro-ph/1/au:+Marzari_F/0/1/0/all/0/1">Francesco Marzari</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+DAngelo_G/0/1/0/all/0/1">Gennaro D&#x27;Angelo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Picogna_G/0/1/0/all/0/1">Giovanni Picogna</a> We investigate via numerical modeling the effects of two planets locked in resonance, and migrating outward, on the dust distribution of the natal circumstellar disk. We aim to test whether the dust distribution exhibits peculiar features arising from the interplay among the gravitational perturbations of the planets in resonance, the evolution of the gas, and its influence on the dust grains’ dynamics. We focus on the 3:2 and 2:1 resonance, where the trapping may be caused by the convergent migration of a Jupiter- andRead More →