RAS_WEB (Page 3,783)

Revisiting the statistical isotropy of GRB sky distribution. (arXiv:1905.08864v1 [astro-ph.CO]) <a href="http://arxiv.org/find/astro-ph/1/au:+Andrade_U/0/1/0/all/0/1">Uendert Andrade</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bengaly_C/0/1/0/all/0/1">Carlos A. P. Bengaly</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Alcaniz_J/0/1/0/all/0/1">Jailson S. Alcaniz</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Capozziello_S/0/1/0/all/0/1">Salvatore Capozziello</a> The assumption of homogeneity and isotropy on large scales is one of the main hypotheses of the standard cosmology. In this paper, we test the assumption of isotropy from the two-point angular correlation function of 2440 gamma-ray bursts (GRB) of the FERMI GRB catalogue. We show that the uncertainties in the GRB positions may induce spurious anisotropic signals in their sky distribution. However, when such uncertainties are taken into account no significant evidence against the large-scale statistical isotropy is found.Read More →

Removal of Galactic foregrounds for the Simons Observatory primordial gravitational wave search. (arXiv:1905.08888v1 [astro-ph.CO]) <a href="http://arxiv.org/find/astro-ph/1/au:+Thorne_B/0/1/0/all/0/1">Ben Thorne</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dunkley_J/0/1/0/all/0/1">Jo Dunkley</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Alonso_D/0/1/0/all/0/1">David Alonso</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Abitbol_M/0/1/0/all/0/1">Maximilian H. Abitbol</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Errard_J/0/1/0/all/0/1">Josquin Errard</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hill_J/0/1/0/all/0/1">J. Colin Hill</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Keating_B/0/1/0/all/0/1">Brian Keating</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Teply_G/0/1/0/all/0/1">Grant Teply</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wollack_E/0/1/0/all/0/1">Edward J. Wollack</a> Upcoming observations from the Simons Observatory have been projected to constrain the tensor-to-scalar ratio, $r$, at the level of $sigma(r)=$0.003. Here we describe one of the forecasting algorithms for the Simons Observatory in more detail, based on cleaning CMB polarization maps using a parametric model. We present a new code to perform this end-to-end forecast, and explore the assumptions in greaterRead More →

GRAMSES: a new route to general relativistic $N$-body simulations in cosmology – I. Methodology and code description. (arXiv:1905.08890v1 [astro-ph.CO]) <a href="http://arxiv.org/find/astro-ph/1/au:+Barrera_Hinojosa_C/0/1/0/all/0/1">Cristian Barrera-Hinojosa</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Li_B/0/1/0/all/0/1">Baojiu Li</a> We present GRAMSES, a new pipeline for nonlinear cosmological $N$-body simulations in General Relativity (GR). This code adopts the Arnowitt-Deser-Misner (ADM) formalism of GR, with constant mean curvature and minimum distortion gauge fixings, which provides a fully nonlinear and background independent framework for relativistic cosmology. Employing the fully constrained formulation, the Einstein equation is reduced to a set of ten elliptical equations solved using multigrid relaxation on adaptive mesh refinements (AMR), and three hyperbolic equations for the evolution of dynamicalRead More →

From Centaurs to comets – 40 years. (arXiv:1905.08892v1 [astro-ph.EP]) <a href="http://arxiv.org/find/astro-ph/1/au:+Peixinho_N/0/1/0/all/0/1">Nuno Peixinho</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Thirouin_A/0/1/0/all/0/1">Audrey Thirouin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tegler_S/0/1/0/all/0/1">Stephen C. Tegler</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sisto_R/0/1/0/all/0/1">Romina P. Di Sisto</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Delsanti_A/0/1/0/all/0/1">Audrey Delsanti</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Guilbert_Lepoutre_A/0/1/0/all/0/1">Aur&#xe9;lie Guilbert-Lepoutre</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bauer_J/0/1/0/all/0/1">James G. Bauer</a> In 1977, while Apple II and Atari computers were being sold, a tiny dot was observed in an inconvenient orbit. The minor body 1977 UB, to be named (2060) Chiron, with an orbit between Saturn and Uranus, became the first Centaur, a new class of minor bodies orbiting roughly between Jupiter and Neptune. The observed overabundance of short-period comets lead to the downfall of the Oort Cloud as exclusive source ofRead More →

Detection of Extensive Optical Emission from the Extremely Radio Faint Galactic Supernova Remnant G182.4+4.3. (arXiv:1905.08901v1 [astro-ph.HE]) <a href="http://arxiv.org/find/astro-ph/1/au:+Fesen_R/0/1/0/all/0/1">Robert Fesen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Neustadt_J/0/1/0/all/0/1">Jack Neustadt</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+How_T/0/1/0/all/0/1">Thomas How</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Black_C/0/1/0/all/0/1">Christine Black</a> Wide-field Halpha images of the radio faint Galactic supernova remnant G182.4+4.2 reveal a surprisingly extensive and complex emission structure, with an unusual series of broad and diffuse filaments along the remnant’s southwestern limb. Deep [O III] 5007 images reveal no appreciable remnant emission with the exception of a single filament coincident with the westernmost of the broad southwest filaments. The near total absence of [O III] emission suggests the majority of the remnant’s optical emission arises fromRead More →

Models of Saturn’s Interior Constructed with Accelerated Concentric Maclaurin Spheroid Method. (arXiv:1905.08907v1 [astro-ph.EP]) <a href="http://arxiv.org/find/astro-ph/1/au:+Militzer_B/0/1/0/all/0/1">B. Militzer</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wahl_S/0/1/0/all/0/1">S. Wahl</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hubbard_W/0/1/0/all/0/1">W. B. Hubbard</a> The Cassini spacecraft’s Grand Finale orbits provided a unique opportunity to probe Saturn’s gravity field and interior structure. Doppler measurements yielded unexpectedly large values for the gravity harmonics J_6, J_8, and J_10 that cannot be matched with planetary interior models that assume uniform rotation. Instead we present a suite of models that assume the planet’s interior rotates on cylinders, which allows us to match all the observed even gravity harmonics. For every interior model, the gravity field is calculated self-consistently with highRead More →

The Physical Nature of Spiral Wave Patterns in Sunspots. (arXiv:1905.08908v1 [astro-ph.SR]) <a href="http://arxiv.org/find/astro-ph/1/au:+Kang_J/0/1/0/all/0/1">Juhyung Kang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Chae_J/0/1/0/all/0/1">Jongchul Chae</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Nakariakov_V/0/1/0/all/0/1">Valery M. Nakariakov</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cho_K/0/1/0/all/0/1">Kyuhyoun Cho</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kwak_H/0/1/0/all/0/1">Hannah Kwak</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lee_K/0/1/0/all/0/1">Kyeore Lee</a> Recently, spiral wave patterns (SWPs) have been detected in 3 minute oscillations of sunspot umbrae, but the nature of this phenomenon has remained elusive. We present a theoretical model that interprets the observed SWPs as the superposition of two different azimuthal modes of slow magnetoacoustic waves driven below the surface in an untwisted and non-rotating magnetic cylinder. We apply this model to SWPs of the line-of-sight (LOS) velocity in a pore observed by the FastRead More →

New cloud morphologies discovered on the Venus’s night during Akatsuki. (arXiv:1905.08913v1 [astro-ph.EP]) <a href="http://arxiv.org/find/astro-ph/1/au:+Peralta_J/0/1/0/all/0/1">J. Peralta</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sanchez_Lavega_A/0/1/0/all/0/1">A. S&#xe1;nchez-Lavega</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Horinouchi_T/0/1/0/all/0/1">T. Horinouchi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+McGouldrick_K/0/1/0/all/0/1">K. McGouldrick</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Garate_Lopez_I/0/1/0/all/0/1">I. Garate-Lopez</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Young_E/0/1/0/all/0/1">E. F. Young</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bullock_M/0/1/0/all/0/1">M. A. Bullock</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lee_Y/0/1/0/all/0/1">Y. J. Lee</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Imamura_T/0/1/0/all/0/1">T. Imamura</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Satoh_T/0/1/0/all/0/1">T. Satoh</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Limaye_S/0/1/0/all/0/1">S. S. Limaye</a> During the years 2016 to 2018, the instruments Akatsuki/IR2 (JAXA) and IRTF/SpeX (NASA) acquired a large set of images at 1.74, 2.26 and 2.32 {mu}m to study the nightside mid-to-lower clouds (48-60 km) of Venus. Here we summarize the rich variety of cloud morphologies apparent in these images: from frequent wave packets and billows caused byRead More →

A double-modulation effect detected in a double-mode high-amplitude $delta$ Scuti star: KIC 10284901. (arXiv:1905.08931v1 [astro-ph.SR]) <a href="http://arxiv.org/find/astro-ph/1/au:+Yang_T/0/1/0/all/0/1">Tao-Zhi Yang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Esamdin_A/0/1/0/all/0/1">Ali Esamdin</a> (XAO/UCAS) In this paper, we present an analysis of the pulsating behaviour of $Kepler$ target KIC 10284901. The Fourier transform of the high-precision light curve reveals 7 independent frequencies for its light variations. Among them, the first two frequencies are main pulsation modes: F0 = 18.994054(1) $rm{d^{-1}}$ and F1 = 24.335804(4) $rm{d^{-1}}$, the ratio of F0/F1 = 0.7805 classify this star as a double-mode high-amplitude $delta$ Scuti (HADS) star; another two frequencies $f_{m1}$ = 0.4407 d$^{-1}$ and $f_{m2}$ = 0.8125 d$^{-1}$ are detected directly,Read More →

Global structure of thermal tides in the upper cloud layer of Venus revealed by the LIR onboard Akatsuki. (arXiv:1905.08947v1 [astro-ph.EP]) <a href="http://arxiv.org/find/astro-ph/1/au:+Kouyama_T/0/1/0/all/0/1">T. Kouyama</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Taguchi_M/0/1/0/all/0/1">M. Taguchi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fukuhara_T/0/1/0/all/0/1">T. Fukuhara</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Imamura_T/0/1/0/all/0/1">T. Imamura</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Horinouchi_T/0/1/0/all/0/1">T. Horinouchi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sato_T/0/1/0/all/0/1">T. M. Sato</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Murakami_S/0/1/0/all/0/1">S. Murakami</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hashimoto_G/0/1/0/all/0/1">G. L. Hashimoto</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lee_Y/0/1/0/all/0/1">Y. J. Lee</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Futaguchi_M/0/1/0/all/0/1">M. Futaguchi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yamada_T/0/1/0/all/0/1">T. Yamada</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Akiba_M/0/1/0/all/0/1">M. Akiba</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Satoh_T/0/1/0/all/0/1">T. Satoh</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Nakamura_M/0/1/0/all/0/1">M. Nakamura</a> Longwave Infrared Camera (LIR) onboard Akatsuki first revealed the global structure of the thermal tides in the upper cloud layer of Venus, where the data coverage was from the equator to the mid-latitudes in both hemispheres and over the wholeRead More →

Binary Stars in the Orion OB1 Association, Subgroup $textit{a}$. (arXiv:1905.08950v1 [astro-ph.SR]) <a href="http://arxiv.org/find/astro-ph/1/au:+Semenko_E/0/1/0/all/0/1">E.A. Semenko</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Romanyuk_I/0/1/0/all/0/1">I.I. Romanyuk</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yakunin_I/0/1/0/all/0/1">I.A. Yakunin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kudryavtsev_D/0/1/0/all/0/1">D.O. Kudryavtsev</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Moiseeva_A/0/1/0/all/0/1">A. V. Moiseeva</a> A detailed spectroscopic survey of chemically peculiar (CP) stars in the Orion OB1 association is the most comprehensive observational program in the field of stellar magnetism that has been carried out at SAO so far. As at the end of 2018, we have completed surveying CP stars in the oldest subgroup $textit{a}$ of the association. In this paper, we give a short overview of CP members of the subgroup showing both direct and indirect signatures of multiplicity. AmongRead More →

Globular Cluster Formation from Colliding Substructure. (arXiv:1905.08951v1 [astro-ph.GA]) <a href="http://arxiv.org/find/astro-ph/1/au:+Madau_P/0/1/0/all/0/1">Piero Madau</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lupi_A/0/1/0/all/0/1">Alessandro Lupi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Diemand_J/0/1/0/all/0/1">Juerg Diemand</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Burkert_A/0/1/0/all/0/1">Andreas Burkert</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lin_D/0/1/0/all/0/1">Douglas N. C. Lin</a> We investigate a scenario where the formation of Globular Clusters (GCs) is triggered by high-speed collisions between infalling atomic-cooling subhalos during the assembly of the main galaxy host, a special dynamical mode of star formation that operates at high gas pressures and is intimately tied to LCDM hierarchical galaxy assembly. The proposed mechanism would give origin to “naked” globulars, as colliding dark matter subhalos and their stars will simply pass through one another while the warm gas within them clashesRead More →

A particular carbon-chain-producing region: L1489 starless core. (arXiv:1905.08952v1 [astro-ph.SR]) <a href="http://arxiv.org/find/astro-ph/1/au:+Wu_Y/0/1/0/all/0/1">Yuefang Wu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lin_L/0/1/0/all/0/1">Lianghao Lin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Liu_X/0/1/0/all/0/1">Xunchuan Liu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Chen_X/0/1/0/all/0/1">Xi Chen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Liu_T/0/1/0/all/0/1">Tie Liu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zhang_C/0/1/0/all/0/1">Chao Zhang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ju_B/0/1/0/all/0/1">Binggang Ju</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yuan_J/0/1/0/all/0/1">Jinghua Yuan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wang_J/0/1/0/all/0/1">Junzhi Wang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Shen_Z/0/1/0/all/0/1">Zhiqiang Shen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kim_K/0/1/0/all/0/1">Kee-Tae Kim</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Qin_S/0/1/0/all/0/1">Sheng-Li Qin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Li_J/0/1/0/all/0/1">Juan Li</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Liu_H/0/1/0/all/0/1">Hongli Liu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zhang_T/0/1/0/all/0/1">Tianwei Zhang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Xu_Y/0/1/0/all/0/1">Ye Xu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Liu_Q/0/1/0/all/0/1">Qinghui Liu</a> We detected carbon-chain molecules (CCMs) HC2n+1N (n=1-3) and C3S in Ku band as well as {high-energy excitation lines including C4H N=9-8, J=17/2-15/2, 19/2-17/2, and CH3CCH J=5-4, K=2 in the 3 mm band toward a starless core called the eastern molecular core (EMC) of L1489 IRS.Read More →