RAS_WEB (Page 2,432)

Barrow holographic dark energy. (arXiv:2005.04115v3 [gr-qc] UPDATED) <a href="http://arxiv.org/find/gr-qc/1/au:+Saridakis_E/0/1/0/all/0/1">Emmanuel N. Saridakis</a> We formulate Barrow holographic dark energy, by applying the usual holographic principle at a cosmological framework, but using the Barrow entropy instead of the standard Bekenstein-Hawking one. The former is an extended black-hole entropy that arises due to quantum-gravitational effects which deform the black-hole surface by giving it an intricate, fractal form. We extract a simple differential equation for the evolution of the dark energy density parameter, which possesses standard holographic dark energy as a limiting sub-case, and we show that the scenario can describe the universe thermal history, with the sequence of matterRead More →

Mildly relativistic magnetized shocks in electron-ion plasmas I. Electromagnetic shock structure. (arXiv:2012.08969v1 [astro-ph.HE]) <a href="http://arxiv.org/find/astro-ph/1/au:+Ligorini_A/0/1/0/all/0/1">Arianna Ligorini</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Niemiec_J/0/1/0/all/0/1">Jacek Niemiec</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kobzar_O/0/1/0/all/0/1">Oleh Kobzar</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Iwamoto_M/0/1/0/all/0/1">Masanori Iwamoto</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bohdan_A/0/1/0/all/0/1">Artem Bohdan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pohl_M/0/1/0/all/0/1">Martin Pohl</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Matsumoto_Y/0/1/0/all/0/1">Yosuke Matsumoto</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Amano_T/0/1/0/all/0/1">Takanobu Amano</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Matsukiyo_S/0/1/0/all/0/1">Shuichi Matsukiyo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Esaki_Y/0/1/0/all/0/1">Yodai Esaki</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hoshino_M/0/1/0/all/0/1">Masahiro Hoshino</a> Mildly relativistic shocks in magnetized electron-ion plasmas are investigated with 2D kinetic particle-in-cell simulations of unprecedentedly high resolution and large scale for conditions that may be found at internal shocks in blazar cores. Ion-scale effects cause corrugations along the shock surface whose properties somewhat depend on the configuration of the mean perpendicular magnetic field, that is either in orRead More →

A Consistent Modeling of Neutrino-driven Wind with Accretion Flow onto a Protoneutron Star and its Implications for $^{56}$Ni Production. (arXiv:2010.05615v2 [astro-ph.HE] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Sawada_R/0/1/0/all/0/1">Ryo Sawada</a> (Kyoto Sangyo Univ.), <a href="http://arxiv.org/find/astro-ph/1/au:+Suwa_Y/0/1/0/all/0/1">Yudai Suwa</a> (Kyoto Sangyo Univ. &amp; YITP, Kyoto Univ.) Details of the explosion mechanism of core-collapse supernovae (CCSNe) are not yet fully understood. There is now an increasing number of successful examples of reproducing explosions in the first-principles simulations, which have shown a slow increase of explosion energy. However, it was recently pointed out that the growth rates of the explosion energy of these simulations are insufficient to produce enough $^{56}$Ni mass to account for observations.Read More →

Sourcing curvature modes with entropy perturbations in non-singular bouncing cosmologies. (arXiv:2012.08249v1 [gr-qc] CROSS LISTED) <a href="http://arxiv.org/find/gr-qc/1/au:+Ijjas_A/0/1/0/all/0/1">Anna Ijjas</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Kolevatov_R/0/1/0/all/0/1">Roman Kolevatov</a> The observed temperature fluctuations in the cosmic microwave background can be traced back to primordial curvature modes that are sourced by adiabatic and/or entropic matter perturbations. In this paper, we explore the entropic mechanism in the context of non-singular bouncing cosmologies. We show that curvature modes are naturally generated during `graceful exit,’ i.e., when the smoothing slow contraction phase ends and the universe enters the bounce stage. Here, the key role is played by the kinetic energy components that come to dominate the energy densityRead More →

The ITRF coordinates of the spherical center of FAST. (arXiv:2012.08359v2 [astro-ph.IM] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Qian_L/0/1/0/all/0/1">Lei Qian</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yue_Y/0/1/0/all/0/1">Youling Yue</a> The ITRF coordinates of the spherical center of the Five-hundred-meter Aperture Spherical radio Telescope (FAST) are $(X,Y,Z)=(-1668557.2070983793,$ $5506838.5266271923, 2744934.9655897617)$. The ITRF coordinates of the spherical center of the Five-hundred-meter Aperture Spherical radio Telescope (FAST) are $(X,Y,Z)=(-1668557.2070983793,$ $5506838.5266271923, 2744934.9655897617)$. http://arxiv.org/icons/sfx.gifRead More →

Mapping Diffuse Emission in Lyman UV band. (arXiv:2012.07384v2 [astro-ph.IM] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Ji_L/0/1/0/all/0/1">Li Ji</a> (1 and 12), <a href="http://arxiv.org/find/astro-ph/1/au:+Lou_Z/0/1/0/all/0/1">Zheng Lou</a> (1), <a href="http://arxiv.org/find/astro-ph/1/au:+Zhang_J/0/1/0/all/0/1">Jinlong Zhang</a> (2), <a href="http://arxiv.org/find/astro-ph/1/au:+Qiu_K/0/1/0/all/0/1">Keqiang Qiu</a> (3), <a href="http://arxiv.org/find/astro-ph/1/au:+Li_S/0/1/0/all/0/1">Shuangying Li</a> (2), <a href="http://arxiv.org/find/astro-ph/1/au:+Sun_W/0/1/0/all/0/1">Wei Sun</a> (1 and 12), <a href="http://arxiv.org/find/astro-ph/1/au:+Yan_S/0/1/0/all/0/1">Shuping Yan</a> (1 and 12), <a href="http://arxiv.org/find/astro-ph/1/au:+Zhang_S/0/1/0/all/0/1">Shuinai Zhang</a> (1 and 12), <a href="http://arxiv.org/find/astro-ph/1/au:+Qian_Y/0/1/0/all/0/1">Yuan Qian</a> (1), <a href="http://arxiv.org/find/astro-ph/1/au:+Wang_S/0/1/0/all/0/1">Sen Wang</a> (4), <a href="http://arxiv.org/find/astro-ph/1/au:+Werner_K/0/1/0/all/0/1">Klaus Werner</a> (5), <a href="http://arxiv.org/find/astro-ph/1/au:+Fang_T/0/1/0/all/0/1">Taotao Fang</a> (6), <a href="http://arxiv.org/find/astro-ph/1/au:+Wang_T/0/1/0/all/0/1">Tinggui Wang</a> (7), <a href="http://arxiv.org/find/astro-ph/1/au:+Barnstedt_J/0/1/0/all/0/1">J&#xfc;rgen Barnstedt</a> (5), <a href="http://arxiv.org/find/astro-ph/1/au:+Buntrock_S/0/1/0/all/0/1">Sebastian Buntrock</a> (5), <a href="http://arxiv.org/find/astro-ph/1/au:+Cai_M/0/1/0/all/0/1">Mingsheng Cai</a> (1 and 12), <a href="http://arxiv.org/find/astro-ph/1/au:+Chen_W/0/1/0/all/0/1">Wen Chen</a> (8), <a href="http://arxiv.org/find/astro-ph/1/au:+Conti_L/0/1/0/all/0/1">Lauro Conti</a> (5), <a href="http://arxiv.org/find/astro-ph/1/au:+Deng_L/0/1/0/all/0/1">Lei Deng</a> (8), <a href="http://arxiv.org/find/astro-ph/1/au:+Diebold_S/0/1/0/all/0/1">Sebastian Diebold</a> (5), <a href="http://arxiv.org/find/astro-ph/1/au:+Fu_S/0/1/0/all/0/1">Shaojun Fu</a> (3), <aRead More →

Internal water storage capacity of terrestrial planets and the effect of hydration on the M-R relation. (arXiv:2012.06455v2 [astro-ph.EP] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Shah_O/0/1/0/all/0/1">Oliver Shah</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Alibert_Y/0/1/0/all/0/1">Yann Alibert</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Helled_R/0/1/0/all/0/1">Ravit Helled</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mezger_K/0/1/0/all/0/1">Klaus Mezger</a> Understanding the chemical interactions between water and Mg-silicates or iron is essential to constrain the interiors of water-rich planets. Hydration effects have, however, been mostly neglected by the astrophysics community so far. As such effects are unlikely to have major impacts on theoretical mass-radius relations this is justified as long as the measurement uncertainties are large. However, upcoming missions, such as the PLATO mission (scheduled launch 2026), are envisaged to reach a precision ofRead More →

Serendipitous discovery of a dusty disc around WDJ181417.84-735459.83. (arXiv:2012.05731v2 [astro-ph.SR] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Egea_E/0/1/0/all/0/1">E. Gonz&#xe1;lez Egea</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Raddi_R/0/1/0/all/0/1">R. Raddi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Koester_D/0/1/0/all/0/1">D. Koester</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Rogers_L/0/1/0/all/0/1">L. K. Rogers</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Marocco_F/0/1/0/all/0/1">F. Marocco</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cooper_W/0/1/0/all/0/1">W. J. Cooper</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Beamin_J/0/1/0/all/0/1">J. C. Beamin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Burningham_B/0/1/0/all/0/1">B. Burningham</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Day_Jones_A/0/1/0/all/0/1">A. Day-Jones</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Forbrich_J/0/1/0/all/0/1">J. Forbrich</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pinfield_D/0/1/0/all/0/1">D. J. Pinfield</a> Spectroscopic observations of white dwarfs reveal that many of them are polluted by exoplanetary material, whose bulk composition can be uniquely probed this way. We present a spectroscopic and photometric analysis of the DA white dwarf WDJ181417.84$-$735459.83, an object originally identified to have a strong infrared excess in the 2MASS and WISE catalogues that we confirmedRead More →

Eppur `e piatto? The cosmic chronometer take on spatial curvature and cosmic concordance. (arXiv:2011.11645v2 [astro-ph.CO] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Vagnozzi_S/0/1/0/all/0/1">Sunny Vagnozzi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Loeb_A/0/1/0/all/0/1">Abraham Loeb</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Moresco_M/0/1/0/all/0/1">Michele Moresco</a> The question of whether Cosmic Microwave Background (CMB) temperature and polarization data from Planck favor a spatially closed Universe with curvature parameter $Omega_K<0$ has been the subject of recent intense discussions. Attempts to break the geometrical degeneracy combining Planck data with external datasets such as Baryon Acoustic Oscillation (BAO) measurements all point towards a spatially flat Universe, at the cost of significant tensions with Planck, which make the resulting dataset combination problematic. Settling this issue requires identifying a dataset whichRead More →

Neutron Star Mergers in AGN Accretion Disks: Cocoon and Ejecta Shock Breakouts. (arXiv:2011.08428v3 [astro-ph.HE] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Zhu_J/0/1/0/all/0/1">Jin-Ping Zhu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zhang_B/0/1/0/all/0/1">Bing Zhang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yu_Y/0/1/0/all/0/1">Yun-Wei Yu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gao_H/0/1/0/all/0/1">He Gao</a> Neutron star mergers are believed to occur in accretion disks around supermassive black holes. Here we show that a putative jet launched from the merger of a binary neutron star (BNS) or a neutron star–black hole (NSBH) merger occurring at the migration trap in an active galactic nucleus (AGN) disk would be choked. The jet energy is deposited within the disk materials to power a hot cocoon. The cocoon is energetic enough to break out from the AGNRead More →

Transient Radio Signatures from Neutron Star Encounters with QCD Axion Miniclusters. (arXiv:2011.05378v2 [hep-ph] UPDATED) <a href="http://arxiv.org/find/hep-ph/1/au:+Edwards_T/0/1/0/all/0/1">Thomas D. P. Edwards</a>, <a href="http://arxiv.org/find/hep-ph/1/au:+Kavanagh_B/0/1/0/all/0/1">Bradley J. Kavanagh</a>, <a href="http://arxiv.org/find/hep-ph/1/au:+Visinelli_L/0/1/0/all/0/1">Luca Visinelli</a>, <a href="http://arxiv.org/find/hep-ph/1/au:+Weniger_C/0/1/0/all/0/1">Christoph Weniger</a> The QCD axion is expected to form dense structures known as axion miniclusters if the Peccei-Quinn symmetry is broken after inflation. Miniclusters that have survived until today would interact with the population of neutron stars (NSs) in the Milky Way to produce transient radio signals from axion-photon conversion in the NS magnetosphere. Here, we quantify the rate, duration, sky location, and brightness of these interactions for two different minicluster internal density profiles. For both density profiles,Read More →

Stellar Disruption of Axion Miniclusters in the Milky Way. (arXiv:2011.05377v2 [astro-ph.GA] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Kavanagh_B/0/1/0/all/0/1">Bradley J. Kavanagh</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Edwards_T/0/1/0/all/0/1">Thomas D. P. Edwards</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Visinelli_L/0/1/0/all/0/1">Luca Visinelli</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Weniger_C/0/1/0/all/0/1">Christoph Weniger</a> Axion miniclusters are dense bound structures of dark matter axions that are predicted to form in the post-inflationary Peccei-Quinn symmetry breaking scenario. Although dense, miniclusters can easily be perturbed or even become unbound by interactions with baryonic objects such as stars. Here, we characterize the spatial distribution and properties of miniclusters in the Milky Way (MW) today after undergoing these stellar interactions throughout their lifetime. We do this by performing a suite of Monte Carlo simulations which trackRead More →

A Sub-Element Adaptive Shock Capturing Approach for Discontinuous Galerkin Methods. (arXiv:2011.03338v3 [math.NA] UPDATED) <a href="http://arxiv.org/find/math/1/au:+Markert_J/0/1/0/all/0/1">Johannes Markert</a>, <a href="http://arxiv.org/find/math/1/au:+Gassner_G/0/1/0/all/0/1">Gregor Gassner</a>, <a href="http://arxiv.org/find/math/1/au:+Walch_S/0/1/0/all/0/1">Stefanie Walch</a> In this paper, a new strategy for a sub-element based shock capturing for discontinuous Galerkin (DG) approximations is presented. The idea is to interpret a DG element as a collection of data and construct a hierarchy of low to high order discretizations on this set of data, including a first order finite volume scheme up to the full order DG scheme. The different DG discretizations are then blended according to sub-element troubled cell indicators, resulting in a final discretization that adaptively blends fromRead More →

Generation of gravitational waves and tidal disruptions in clumpy galaxies. (arXiv:2011.02488v2 [astro-ph.GA] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Pestoni_B/0/1/0/all/0/1">Boris Pestoni</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bortolas_E/0/1/0/all/0/1">Elisa Bortolas</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Capelo_P/0/1/0/all/0/1">Pedro R. Capelo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mayer_L/0/1/0/all/0/1">Lucio Mayer</a> Obtaining a better understanding of intermediate-mass black holes (IMBHs) is crucial, as their properties could shed light on the origin and growth of their supermassive counterparts. Massive star-forming clumps, which are present in a large fraction of massive galaxies at $z sim$ 1-3, are amongst the venues wherein IMBHs could reside. We perform a series of Fokker-Planck simulations to explore the occurrence of tidal disruption (TD) and gravitational wave (GW) events about an IMBH in a massive star-forming clump,Read More →

Nanohertz gravitational waves from NEC violation in the early universe. (arXiv:2011.01605v2 [gr-qc] UPDATED) <a href="http://arxiv.org/find/gr-qc/1/au:+Tahara_H/0/1/0/all/0/1">Hiroaki W. H. Tahara</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Kobayashi_T/0/1/0/all/0/1">Tsutomu Kobayashi</a> We study nanohertz gravitational waves relevant to pulsar timing array experiments from quantum fluctuations in the early universe with null energy condition (NEC) violation. The NEC violation admits accelerated expansion with the scale factor $apropto (-t)^{-p}$ ($p>0$), which gives the tensor spectral index $n_t=2/(p+1)>0$. To evade the constraint from Big Bang nucleosynthesis (BBN), we connect the NEC-violating phase to a subsequent short slow-roll inflationary phase which ends with standard reheating, and thereby reduce the high frequency part of the spectrum. An explicit model isRead More →

Fink, a new generation of broker for the LSST community. (arXiv:2009.10185v3 [astro-ph.IM] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Moller_A/0/1/0/all/0/1">Anais M&#xf6;ller</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Peloton_J/0/1/0/all/0/1">Julien Peloton</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ishida_E/0/1/0/all/0/1">Emille E. O. Ishida</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Arnault_C/0/1/0/all/0/1">Chris Arnault</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bachelet_E/0/1/0/all/0/1">Etienne Bachelet</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Blaineau_T/0/1/0/all/0/1">Tristan Blaineau</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Boutigny_D/0/1/0/all/0/1">Dominique Boutigny</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Chauhan_A/0/1/0/all/0/1">Abhishek Chauhan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gangler_E/0/1/0/all/0/1">Emmanuel Gangler</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hernandez_F/0/1/0/all/0/1">Fabio Hernandez</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hrivnac_J/0/1/0/all/0/1">Julius Hrivnac</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Leoni_M/0/1/0/all/0/1">Marco Leoni</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Leroy_N/0/1/0/all/0/1">Nicolas Leroy</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Moniez_M/0/1/0/all/0/1">Marc Moniez</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pateyron_S/0/1/0/all/0/1">Sacha Pateyron</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ramparison_A/0/1/0/all/0/1">Adrien Ramparison</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Turpin_D/0/1/0/all/0/1">Damien Turpin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ansari_R/0/1/0/all/0/1">R&#xe9;za Ansari</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Allam_T/0/1/0/all/0/1">Tarek Allam Jr.</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bajat_A/0/1/0/all/0/1">Armelle Bajat</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Biswas_B/0/1/0/all/0/1">Biswajit Biswas</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Boucaud_A/0/1/0/all/0/1">Alexandre Boucaud</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bregeon_J/0/1/0/all/0/1">Johan Bregeon</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Campagne_J/0/1/0/all/0/1">Jean-Eric Campagne</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cohen_Tanugi_J/0/1/0/all/0/1">Johann Cohen-Tanugi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Coleiro_A/0/1/0/all/0/1">Alexis Coleiro</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dornic_D/0/1/0/all/0/1">Damien Dornic</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fouchez_D/0/1/0/all/0/1">Dominique Fouchez</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Godet_O/0/1/0/all/0/1">Olivier Godet</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gris_P/0/1/0/all/0/1">PhilippeRead More →

Mapping the spectral index of Cas A: evidence for flattening from radio to infrared. (arXiv:2005.12677v2 [astro-ph.HE] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Domcek_V/0/1/0/all/0/1">V. Dom&#x10d;ek</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Vink_J/0/1/0/all/0/1">J. Vink</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Santisteban_J/0/1/0/all/0/1">J.V. Hern&#xe1;ndez Santisteban</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Delaney_T/0/1/0/all/0/1">T. Delaney</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zhou_P/0/1/0/all/0/1">P. Zhou</a> Synchrotron radiation from supernova remnants are caused by electrons accelerated through diffusive shock acceleration (DSA). The standard DSA theory predicts an electron spectral index of $p=2$, corresponding to a radio spectral index of $alpha=-0.5$. An extension of DSA predicts that the accelerated particles changes the shock structure, resulting in a spectrum that is steeper than $p>2$ ($alpha<-0.5$) at low energies and flattens with energy. For Cas A, a synchrotron spectral flattening wasRead More →

New Open Clusters Found by Manual Mining of Data in Gaia DR2. (arXiv:2009.04751v2 [astro-ph.SR] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Casado_J/0/1/0/all/0/1">Juan Casado</a> The physical nature of a series of 20 new open clusters is confirmed employing existing data on putative star members, mainly from second Gaia Data Release (DR2). The clusters were discovered as overdensities of stars by visual inspection of either photographic DSS plates or proper motion plots of random source fields. The reported objects are not present in the most comprehensive or recent catalogs of stellar clusters and associations. For all of them, clumps of comoving stars are revealed in the proper motion space. The parallaxes ofRead More →

Looking for the possible gluon condensation signature in sub-TeV gamma-ray spectra: from active galactic nuclei to gamma ray bursts. (arXiv:2009.01984v2 [astro-ph.HE] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Zhu_W/0/1/0/all/0/1">Wei Zhu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zheng_Z/0/1/0/all/0/1">Zechun Zheng</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Liu_P/0/1/0/all/0/1">Peng Liu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wan_L/0/1/0/all/0/1">Lihong Wan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ruan_J/0/1/0/all/0/1">Jianhong Ruan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wang_F/0/1/0/all/0/1">Fan Wang</a> The gluon condensation in the proton as a dynamical model is used to treat a series of unsolved puzzles in sub-TeV gamma ray spectra, they include the broken power-law of blazar’s radiation, the hardening confusion of 1ES 1426+428, Mkn 501, and the recently recorded sub-TeV gamma spectra of GRB 180720B and GRB 190114C. We find that the above anomalous phenomena in gamma ray energy spectraRead More →

The time-scales probed by star formation rate indicators for realistic, bursty star formation histories from the FIRE simulations. (arXiv:2008.08582v2 [astro-ph.GA] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Velazquez_J/0/1/0/all/0/1">Jos&#xe9; A. Flores Vel&#xe1;zquez</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gurvich_A/0/1/0/all/0/1">Alexander B. Gurvich</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Faucher_Giguere_C/0/1/0/all/0/1">Claude-Andr&#xe9; Faucher-Gigu&#xe8;re</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bullock_J/0/1/0/all/0/1">James S. Bullock</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Starkenburg_T/0/1/0/all/0/1">Tjitske K. Starkenburg</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Moreno_J/0/1/0/all/0/1">Jorge Moreno</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lazar_A/0/1/0/all/0/1">Alexandres Lazar</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mercado_F/0/1/0/all/0/1">Francisco J. Mercado</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Stern_J/0/1/0/all/0/1">Jonathan Stern</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sparre_M/0/1/0/all/0/1">Martin Sparre</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hayward_C/0/1/0/all/0/1">Christopher C. Hayward</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wetzel_A/0/1/0/all/0/1">Andrew Wetzel</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+El_Badry_K/0/1/0/all/0/1">Kareem El-Badry</a> Understanding the rate at which stars form is central to studies of galaxy formation. Observationally, the star formation rates (SFRs) of galaxies are measured using the luminosity in different frequency bands, often under the assumption of a time-steadyRead More →