August 2020 (Page 60)

DART Mission Determination of Momentum Transfer: Model of Ejecta Plume Observations. (arXiv:2007.15761v1 [astro-ph.EP]) <a href="http://arxiv.org/find/astro-ph/1/au:+Cheng_A/0/1/0/all/0/1">Andrew F. Cheng</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Stickle_A/0/1/0/all/0/1">Angela M. Stickle</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fahnestock_E/0/1/0/all/0/1">Eugene G. Fahnestock</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dotto_E/0/1/0/all/0/1">Elisabetta Dotto</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Corte_V/0/1/0/all/0/1">Vincenzo Della Corte</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:+Rivkin_A/0/1/0/all/0/1">Andrew S. Rivkin</a> The NASA Double Asteroid Redirection Test (DART) spacecraft will impact the secondary member of the [65803] Didymos binary in order to perform the first demonstration of asteroid deflection by kinetic impact. Determination of the momentum transfer to the target body from the kinetic impact is a primary planetary defense objective, using ground-based telescopic observations of the orbital period change of Didymos and imaging of theRead More →

The Abundance Pattern of $alpha$ elements in the Triangulum-Andromeda Overdensity. (arXiv:2007.15764v1 [astro-ph.GA]) <a href="http://arxiv.org/find/astro-ph/1/au:+Silva_J/0/1/0/all/0/1">J. V. Sales Silva</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cunha_K/0/1/0/all/0/1">K. Cunha</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Perottoni_H/0/1/0/all/0/1">H. D. Perottoni</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Rocha_Pinto_H/0/1/0/all/0/1">H. J. Rocha-Pinto</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Daflon_S/0/1/0/all/0/1">S. Daflon</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Almeida_Fernandes_F/0/1/0/all/0/1">F. Almeida-Fernandes</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Souto_D/0/1/0/all/0/1">Diogo Souto</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Majewski_S/0/1/0/all/0/1">S. R. Majewski</a> The close relationship between the nature of the Triangulum-Andromeda (TriAnd) overdensity and the Galactic disk has become increasingly evident in recent years. However, the chemical pattern of this overdensity (R$_{GC}$ = 20 – 30 kpc) is unique and differs from what we know of the local disk. In this study, we analyze the chemical abundances of five $alpha$ elements (Mg, O, Si, Ca, andRead More →

The Saturn Ring Skimmer Mission Concept: The next step to explore Saturn’s rings, atmosphere, interior and inner magnetosphere. (arXiv:2007.15767v1 [astro-ph.IM]) <a href="http://arxiv.org/find/astro-ph/1/au:+Tiscareno_M/0/1/0/all/0/1">Matthew S. Tiscareno</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Vaquero_M/0/1/0/all/0/1">Mar Vaquero</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hedman_M/0/1/0/all/0/1">Matthew M. Hedman</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cao_H/0/1/0/all/0/1">Hao Cao</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Estrada_P/0/1/0/all/0/1">Paul R. Estrada</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ingersoll_A/0/1/0/all/0/1">Andrew P. Ingersoll</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Miller_K/0/1/0/all/0/1">Kelly E. Miller</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Parisi_M/0/1/0/all/0/1">Marzia Parisi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Atkinson_D/0/1/0/all/0/1">David. H. Atkinson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Brooks_S/0/1/0/all/0/1">Shawn M. Brooks</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cuzzi_J/0/1/0/all/0/1">Jeffrey N. Cuzzi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fuller_J/0/1/0/all/0/1">James Fuller</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hendrix_A/0/1/0/all/0/1">Amanda R. Hendrix</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Johnson_R/0/1/0/all/0/1">Robert E. Johnson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Koskinen_T/0/1/0/all/0/1">Tommi Koskinen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kurth_W/0/1/0/all/0/1">William S. Kurth</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lunine_J/0/1/0/all/0/1">Jonathan I. Lunine</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Nicholson_P/0/1/0/all/0/1">Philip D. Nicholson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Paty_C/0/1/0/all/0/1">Carol S. Paty</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Schindhelm_R/0/1/0/all/0/1">Rebecca Schindhelm</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Showalter_M/0/1/0/all/0/1">Mark R. Showalter</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Spilker_L/0/1/0/all/0/1">Linda J. Spilker</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Strange_N/0/1/0/all/0/1">Nathan J.Read More →

Diffusive hydrogenation reactions of CO embedded in amorphous solid water at elevated temperatures ~70 K. (arXiv:2007.15782v1 [astro-ph.GA]) <a href="http://arxiv.org/find/astro-ph/1/au:+Tsuge_M/0/1/0/all/0/1">Masashi Tsuge</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hidaka_H/0/1/0/all/0/1">Hiroshi Hidaka</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kouchi_A/0/1/0/all/0/1">Akira Kouchi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Watanabe_N/0/1/0/all/0/1">Naoki Watanabe</a> The surface processes on interstellar dust grains have an important role in the chemical evolution in molecular clouds. Hydrogenation reactions on ice surfaces have been extensively investigated and are known to proceed at low temperatures mostly below 20 K. In contrast, information about the chemical processes of molecules within an ice mantle is lacking. In this work, we investigated diffusive hydrogenation reactions of carbon monoxide (CO) embedded in amorphous solid water (ASW) as a model caseRead More →

Discovering the Sky at the Longest wavelengths with a lunar orbit array. (arXiv:2007.15794v1 [astro-ph.IM]) <a href="http://arxiv.org/find/astro-ph/1/au:+Chen_X/0/1/0/all/0/1">Xuelei Chen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yan_J/0/1/0/all/0/1">Jingye Yan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Deng_L/0/1/0/all/0/1">Li Deng</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wu_F/0/1/0/all/0/1">Fengquan Wu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wu_L/0/1/0/all/0/1">Lin Wu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Xu_Y/0/1/0/all/0/1">Yidong Xu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zhou_L/0/1/0/all/0/1">Li Zhou</a> Due to ionosphere absorption and the interference by natural and artificial radio emissions, astronomical observation from the ground becomes very difficult at the wavelengths of decametre or longer, which we shall refer as the ultralong wavelengths. This unexplored part of electromagnetic spectrum has the potential of great discoveries, notably in the study of cosmic dark ages and dawn, but also in heliophysics and space weather, planets and exoplanets, cosmic rayRead More →

ACRONYM IV: Three New, Young, Low-mass Spectroscopic Binaries. (arXiv:2007.15799v1 [astro-ph.SR]) <a href="http://arxiv.org/find/astro-ph/1/au:+Flagg_L/0/1/0/all/0/1">Laura Flagg</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Shkolnik_E/0/1/0/all/0/1">Evgenya L. Shkolnik</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Weinberger_A/0/1/0/all/0/1">Alycia Weinberger</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bowler_B/0/1/0/all/0/1">Brendan P. Bowler</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Skiff_B/0/1/0/all/0/1">Brian Skiff</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kraus_A/0/1/0/all/0/1">Adam L. Kraus</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Liu_M/0/1/0/all/0/1">Michael C. Liu</a> As part of our search for new low-mass members of nearby young moving groups (YMG), we discovered three low-mass, spectroscopic binaries, two of which are not kinematically associated with any known YMG. Using high-resolution optical spectroscopy, we measure the component and systemic radial velocities of the systems, as well as their lithium absorption and H$alpha$ emission, both spectroscopic indicators of youth. One system (2MASS J02543316-5108313, M2.0+M3.0) we confirm as aRead More →

Possible Time Correlation Between Jet Ejection and Mass Accretion for RW Aur A. (arXiv:2007.15848v1 [astro-ph.SR]) <a href="http://arxiv.org/find/astro-ph/1/au:+Takami_M/0/1/0/all/0/1">Michihiro Takami</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Beck_T/0/1/0/all/0/1">Tracy L. Beck</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Schneider_P/0/1/0/all/0/1">P. Christian Schneider</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Guenther_H/0/1/0/all/0/1">Hans Moritz Guenther</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+White_M/0/1/0/all/0/1">Marc White</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Grankin_K/0/1/0/all/0/1">Konstantin Grankin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Karr_J/0/1/0/all/0/1">Jennifer L. Karr</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ohyama_Y/0/1/0/all/0/1">Youichi Ohyama</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Coffey_D/0/1/0/all/0/1">Deirdre Coffey</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Liu_H/0/1/0/all/0/1">Hauyu Baobab Liu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Galvan_Madrid_R/0/1/0/all/0/1">Roberto Galvan-Madrid</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Liu_C/0/1/0/all/0/1">Chun-Fan Liu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fukagawa_M/0/1/0/all/0/1">Misato Fukagawa</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Manset_N/0/1/0/all/0/1">Nadine Manset</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Chen_W/0/1/0/all/0/1">Wen-Ping Chen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pyo_T/0/1/0/all/0/1">Tae-Soo Pyo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Shang_H/0/1/0/all/0/1">Hsien Shang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ray_T/0/1/0/all/0/1">Thomas P. Ray</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Otsuka_M/0/1/0/all/0/1">Masaaki Otsuka</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Chou_M/0/1/0/all/0/1">Mei-Yin Chou</a> For the active T-Taur star RW Aur A we have performed long-term (~10 yr) monitoring observations of (1) jet imaging in the [Fe II]Read More →

The Red Supergiant Binary Fraction of the Large Magellanic Cloud. (arXiv:2007.15852v1 [astro-ph.SR]) <a href="http://arxiv.org/find/astro-ph/1/au:+Neugent_K/0/1/0/all/0/1">Kathryn F. Neugent</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Levesque_E/0/1/0/all/0/1">Emily M. Levesque</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Massey_P/0/1/0/all/0/1">Philip Massey</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Morrell_N/0/1/0/all/0/1">Nidia I. Morrell</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Drout_M/0/1/0/all/0/1">Maria R. Drout</a> The binary fraction of unevolved massive stars is thought to be 70-100% but there are few observational constraints on the binary fraction of the evolved version of a subset of these stars, the red supergiants (RSGs). Here we identify a complete sample of RSGs in the Large Magellanic Cloud (LMC) using new spectroscopic observations and archival UV, IR and broadband optical photometry. We find 4090 RSGs with log L/Lo > 3.5 with 1820 ofRead More →

Seamless maps of major elements of the Moon: Results from high-resolution geostationary satellite. (arXiv:2007.15858v1 [astro-ph.EP]) <a href="http://arxiv.org/find/astro-ph/1/au:+Lu_Y/0/1/0/all/0/1">Yu Lu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wu_Y/0/1/0/all/0/1">Yun-Zhao Wu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Li_C/0/1/0/all/0/1">Cui Li</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ma_J/0/1/0/all/0/1">Jin-Song Ma</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Qi_W/0/1/0/all/0/1">Wen-Wen Qi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tan_W/0/1/0/all/0/1">Wei Tan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Li_X/0/1/0/all/0/1">Xiao-Man Li</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Shi_Z/0/1/0/all/0/1">Zhi-Cheng Shi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+He_H/0/1/0/all/0/1">Hong-Yan He</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dai_S/0/1/0/all/0/1">Shu-Wu Dai</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Li_G/0/1/0/all/0/1">Guo Li</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Liu_F/0/1/0/all/0/1">Feng-Jing Liu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wang_J/0/1/0/all/0/1">Jing-Qiao Wang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wang_X/0/1/0/all/0/1">Xiao-Yan Wang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wang_Q/0/1/0/all/0/1">Qi Wang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Meng_L/0/1/0/all/0/1">Ling-Jie Meng</a> Major elements such as Fe, Ti, Mg, Al, Ca, and Si play very important roles in understanding the origin and evolution of the Moon. Previous maps of these major elements derived from orbital data are based on mosaic images or low-resolution GammaRead More →

Constraining the origin and models of chemical enrichment in galaxy clusters using the Athena X-IFU. (arXiv:2007.15910v1 [astro-ph.GA]) <a href="http://arxiv.org/find/astro-ph/1/au:+Mernier_F/0/1/0/all/0/1">F. Mernier</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cucchetti_E/0/1/0/all/0/1">E. Cucchetti</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tornatore_L/0/1/0/all/0/1">L. Tornatore</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Biffi_V/0/1/0/all/0/1">V. Biffi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pointecouteau_E/0/1/0/all/0/1">E. Pointecouteau</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Clerc_N/0/1/0/all/0/1">N. Clerc</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Peille_P/0/1/0/all/0/1">P. Peille</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Rasia_E/0/1/0/all/0/1">E. Rasia</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Barret_D/0/1/0/all/0/1">D. Barret</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Borgani_S/0/1/0/all/0/1">S. Borgani</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bulbul_E/0/1/0/all/0/1">E. Bulbul</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dauser_T/0/1/0/all/0/1">T. Dauser</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dolag_K/0/1/0/all/0/1">K. Dolag</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ettori_S/0/1/0/all/0/1">S. Ettori</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gaspari_M/0/1/0/all/0/1">M. Gaspari</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pajot_F/0/1/0/all/0/1">F. Pajot</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Roncarelli_M/0/1/0/all/0/1">M. Roncarelli</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wilms_J/0/1/0/all/0/1">J. Wilms</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Nous_C/0/1/0/all/0/1">C. No&#xfb;s</a> The chemical enrichment of the Universe at all scales is related to stellar winds and explosive supernovae phenomena. Metals produced by stars and later spread at the mega-parsec scale through theRead More →

Impact of the reflection model on the estimate of the properties of accreting black holes. (arXiv:2007.15914v1 [astro-ph.HE]) <a href="http://arxiv.org/find/astro-ph/1/au:+Tripathi_A/0/1/0/all/0/1">Ashutosh Tripathi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Liu_H/0/1/0/all/0/1">Honghui Liu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bambi_C/0/1/0/all/0/1">Cosimo Bambi</a> Relativistic reflection features in the X-ray spectra of black hole binaries and AGNs originate from illumination of the inner part of the accretion disk by a hot corona. In the presence of high quality data and with the correct astrophysical model, X-ray reflection spectroscopy can be quite a powerful tool to probe the strong gravity region, study the morphology of the accreting matter, measure black hole spins, and even test Einstein’s theory of general relativity in the strong fieldRead More →

Temporal evolution of short-lived penumbral microjets. (arXiv:2007.15926v1 [astro-ph.SR]) <a href="http://arxiv.org/find/astro-ph/1/au:+Siu_Tapia_A/0/1/0/all/0/1">A. Siu-Tapia</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Rubio_L/0/1/0/all/0/1">L. R. Bellot Rubio</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Suarez_D/0/1/0/all/0/1">D. Orozco Su&#xe1;rez</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gafeira_R/0/1/0/all/0/1">R. Gafeira</a> Context. Penumbral microjets are elongated jet-like brightenings observed in the chromosphere above sunspot penumbrae. They are transient events that last from a few seconds to several minutes and are thought to originate from magnetic reconnection processes. Previous studies have mainly focused on their morphological and spectral characteristics, and more recently on their spectropolarimetric signals during the maximum brightness stage. Studies addressing the temporal evolution of PMJs have also been carried out, but they are based on spatial and spectral time variations only.Read More →

Towards a more rigorous treatment of uncertainties on the velocity distribution of dark matter particles for capture in stars. (arXiv:2007.15927v1 [astro-ph.CO]) <a href="http://arxiv.org/find/astro-ph/1/au:+Lopes_J/0/1/0/all/0/1">Jos&#xe9; Lopes</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lacroix_T/0/1/0/all/0/1">Thomas Lacroix</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lopes_I/0/1/0/all/0/1">Il&#xed;dio Lopes</a> Dark matter (DM) capture in stars offers a rich phenomenology that makes it possible to probe a wide variety of particle DM scenarios in diverse astrophysical environments. In spite of decades of improvements to refine predictions of capture-related observables and better quantify astrophysical and particle-physics uncertainties, the actual impact of the Galactic phase-space distribution function of DM has been overlooked. In this work, we tackle this problem by making use of self-consistent equilibrium phase-space modelsRead More →

Revisiting a non-parametric reconstruction of the deceleration parameter from observational data. (arXiv:2007.15941v1 [astro-ph.CO]) <a href="http://arxiv.org/find/astro-ph/1/au:+Mukherjee_P/0/1/0/all/0/1">Purba Mukherjee</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Banerjee_N/0/1/0/all/0/1">Narayan Banerjee</a> A non-parametric reconstruction of the deceleration parameter $q$ is carried out. The observational datasets are so chosen that they are model independent as much as possible. The present acceleration and the epoch at which the cosmic acceleration sets in is quite as expected, but beyond a certain redshift ($z sim 2$), a negative value of $q$ appears to be in the allowed region. A survey of existing literature is given and compared with the results obtained in the present work. A non-parametric reconstruction of the decelerationRead More →

The Milky Way’s nuclear star cluster: Old, metal-rich, and cuspy. (arXiv:2007.15950v1 [astro-ph.GA]) <a href="http://arxiv.org/find/astro-ph/1/au:+Schodel_R/0/1/0/all/0/1">R. Sch&#xf6;del</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Nogueras_Lara_F/0/1/0/all/0/1">F. Nogueras-Lara</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gallego_Cano_E/0/1/0/all/0/1">E. Gallego-Cano</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Shahzamanian_B/0/1/0/all/0/1">B. Shahzamanian</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gallego_Calvente_A/0/1/0/all/0/1">A. T. Gallego-Calvente</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gardini_A/0/1/0/all/0/1">A. Gardini</a> (abridged) We provide Ks photometry for roughly 39,000 stars and H-band photometry for about 11,000 stars within a field of about 40″x40″, centred on Sgr A*. In addition, we provide Ks photometry of about 3,000 stars in a very deep central field of 10″x10″, centred on Sgr A*. We find that the Ks luminosity function (KLF) is rather homogeneous within the studied field and does not show any significant changes as a function ofRead More →

Magnetohydrodynamics of protoplanetary discs. (arXiv:2007.15967v1 [astro-ph.SR]) <a href="http://arxiv.org/find/astro-ph/1/au:+Lesur_G/0/1/0/all/0/1">G. Lesur</a> Protoplanetary discs are made of gas and dust orbiting a young star. They are also the birth place of planetary systems, which motivates a large amount of observational and theoretical research. In these lecture notes, I present a review of the magnetic mechanisms applied to the outer regions R>1 AU of these discs, which are the planet-formation regions. In contrast to usual astrophysical plasmas, the gas in these regions is noticeably cold (T<300 K) and dense, which implies a very low ionisation fraction close to the disc midplane. In these notes, I deliberately ignore the innermostRead More →

Gamma Rays from UltraCompact Minihaloes: Effects on the Earth’s Atmosphere and Links to Mass Extinction Events. (arXiv:2007.15975v1 [astro-ph.HE]) <a href="http://arxiv.org/find/astro-ph/1/au:+Sarkis_M/0/1/0/all/0/1">M. Sarkis</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Beck_G/0/1/0/all/0/1">G. Beck</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Thomas_B/0/1/0/all/0/1">B. C. Thomas</a> Recent studies of the effects on the Earth’s atmosphere by astrophysical sources, such as nearby gamma-ray bursts or supernovae, have shown that these events could lead to severe changes in atmospheric composition. Depletion of ozone, the most notable of these changes, is extremely dangerous to living organisms as any decrease in ozone levels leads to an increase in the irradiance of harmful solar radiation at the Earth’s surface. In this work we consider dark matter as anRead More →

X-ray study of the merging galaxy cluster Abell 3411-3412 with XMM-Newton and Suzaku. (arXiv:2007.15976v1 [astro-ph.HE]) <a href="http://arxiv.org/find/astro-ph/1/au:+Zhang_X/0/1/0/all/0/1">X. Zhang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Simionescu_A/0/1/0/all/0/1">A. Simionescu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Akamatsu_H/0/1/0/all/0/1">H. Akamatsu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kaastra_J/0/1/0/all/0/1">J. S. Kaastra</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Plaa_J/0/1/0/all/0/1">J. de Plaa</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Weeren_R/0/1/0/all/0/1">R. J. van Weeren</a> Context: Chandra observations of the Abell 3411-3412 merging system have revealed an outbound bullet-like sub-cluster in the northern part and many surface brightness (SB) edges at the southern periphery, where multiple diffuse sources are also reported from radio observations. Notably, a south-eastern radio relic associated with fossil plasma from a radio galaxy and with a detected X-ray edge provides direct evidence of shock re-acceleration. The properties of theRead More →

Planetary System from the Outer Edge of the Inner Void — Classes and Populations of Variety. (arXiv:2007.15979v1 [astro-ph.EP]) <a href="http://arxiv.org/find/astro-ph/1/au:+Morikawa_M/0/1/0/all/0/1">Masahiro Morikawa</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Amaya_S/0/1/0/all/0/1">Suzuka Amaya</a> Planets are common objects in the Universe, observationally as well as theoretically. However, the standard theory of their formation encounters many difficulties, such as dust fall and disk lifetime problems. We positively analyze them, expecting that those problems as a whole may indicate some consistent effective model. Thus we propose a dynamical model of the planet formation based on the assumption that the inner void of gas is commonly formed in the disk without specifying any Physical origin. The basic processesRead More →

Two-fluid simulations of Rayleigh-Taylor instability in a magnetized solar prominence thread. I. Effects of prominence magnetization and mass loading. (arXiv:2007.15984v1 [astro-ph.SR]) <a href="http://arxiv.org/find/astro-ph/1/au:+Braileanu_B/0/1/0/all/0/1">B. Popescu Braileanu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lukin_V/0/1/0/all/0/1">V. S. Lukin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Khomenko_E/0/1/0/all/0/1">E. Khomenko</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Vicente_A/0/1/0/all/0/1">A. de Vicente</a> Solar prominences are formed by partially ionized plasma with inter-particle collision frequencies generally warranting magnetohydrodynamic treatment. In this work, we explore the dynamical impacts and observable signatures of two-fluid effects in the parameter regimes when ion-neutral collisions do not fully couple the neutral and charged fluids. We perform 2.5D two-fluid (charges – neutrals) simulations of the Rayleigh-Taylor instability (RTI) at a smoothly changing interface between a solar prominence threadRead More →