RAS_WEB (Page 4,386)

Archives of CrAO spectral observations. Catalogues of objects and images. (arXiv:1903.10633v1 [astro-ph.IM]) <a href="http://arxiv.org/find/astro-ph/1/au:+Shlyapnikov_A/0/1/0/all/0/1">A.A. Shlyapnikov</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gorbunov_M/0/1/0/all/0/1">M.A. Gorbunov</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gorbachev_M/0/1/0/all/0/1">M.A. Gorbachev</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Akmetdinov_R/0/1/0/all/0/1">R.R. Akmetdinov</a> The work described in this article is a continuation of the previously initiated research on archival spectral observations carried out in the Crimea. It covers a time interval of about 90 years and contains information about spectroscopy using various facilities: from the wide-angle astrographs with an objective prism to the main CrAO telescope – ZTSh. A brief history of telescopes and their equipment are presented. The article is illustrated with the possibilities of network access to the catalogues of observations takenRead More →

The Panchromatic Circumgalactic Medium. (arXiv:1903.10649v1 [astro-ph.GA]) <a href="http://arxiv.org/find/astro-ph/1/au:+Wang_Q/0/1/0/all/0/1">Q.Daniel Wang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Burchett_J/0/1/0/all/0/1">Joseph N. Burchett</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lehner_N/0/1/0/all/0/1">Nicolas Lehner</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+OMeara_J/0/1/0/all/0/1">John M. O&#x27;Meara</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Peeples_M/0/1/0/all/0/1">Molly S. Peeples</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Peek_J/0/1/0/all/0/1">J. E. G. Peek</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Rafelski_M/0/1/0/all/0/1">Marc Rafelski</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tumlinson_J/0/1/0/all/0/1">Jason Tumlinson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Werk_J/0/1/0/all/0/1">Jessica Werk</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zaritsky_D/0/1/0/all/0/1">Dennis Zaritsky</a> Galaxies are surrounded by extended atmospheres, which are often called the circumgalactic medium (CGM) and are the least understood part of galactic ecosystems. The CGM serves as a reservoir of both diffuse, metal-poor gas accreted from the intergalactic medium, and metal-rich gas that is either ejected from galaxies by energetic feedback or stripped from infalling satellites. As such, the CGM is empirically multi-phased andRead More →

Radio follow-up of a candidate gamma-ray transient in the sky localization area of GW170608. (arXiv:1903.10660v1 [astro-ph.HE]) <a href="http://arxiv.org/find/astro-ph/1/au:+Artkop_K/0/1/0/all/0/1">Kyle Artkop</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Smith_R/0/1/0/all/0/1">Rachel Smith</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Corsi_A/0/1/0/all/0/1">Alessandra Corsi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Giacintucci_S/0/1/0/all/0/1">Simona Giacintucci</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Peters_W/0/1/0/all/0/1">Wendy M. Peters</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Perna_R/0/1/0/all/0/1">Rosalba Perna</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cenko_S/0/1/0/all/0/1">S. Bradley Cenko</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Clarke_T/0/1/0/all/0/1">Tracy E. Clarke</a> After the identification of a candidate $gamma$-ray transient in the error region of the binary black hole (BBH) merger GW150914 by the textit{Fermi} satellite, the question of whether BBH mergers can be associated to electromagnetic counterparts remains highly debated. Here, we present radio follow-up observations of GW170608, a BBH merger that occurred during the second observing run (O2) of the Advanced LaserRead More →

Understanding Exoplanet Atmospheres with UV Observations II: The Far UV and Atmospheric Escape. (arXiv:1903.10669v1 [astro-ph.EP]) <a href="http://arxiv.org/find/astro-ph/1/au:+Lopez_E/0/1/0/all/0/1">Eric D. Lopez</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Airapetian_V/0/1/0/all/0/1">Vladimir Airapetian</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Christiansen_J/0/1/0/all/0/1">Jessie Christiansen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fossati_L/0/1/0/all/0/1">Luca Fossati</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+France_K/0/1/0/all/0/1">Kevin France</a> Much of the focus of exoplanet atmosphere analysis in the coming decade will be at infrared wavelengths, with the planned launches of the James Webb Space Telescope (JWST) and the Wide-Field Infrared Survey Telescope (WFIRST). However, without being placed in the context of broader wavelength coverage, especially in the optical and ultraviolet, infrared observations produce an incomplete picture of exoplanet atmospheres. Scattering information encoded in blue optical and near-UV (NUV) observations can help determineRead More →

The Messenger: a galactic centre gravitational-wave beacon. (arXiv:1903.10698v1 [astro-ph.HE]) <a href="http://arxiv.org/find/astro-ph/1/au:+Abramowicz_M/0/1/0/all/0/1">Marek Abramowicz</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bejger_M/0/1/0/all/0/1">Michal Bejger</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gourgoulhon_E/0/1/0/all/0/1">Eric Gourgoulhon</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Straub_O/0/1/0/all/0/1">Odele Straub</a> Our existence in the Universe resulted from a rare combination of circumstances. The same must be true for any advanced extraterrestrial civilisation. If there exist any in the Milky Way, they are likely scattered over large distances in space and time, however, they must be aware of the unique property of the Galactic centre: it hosts the closest massive black hole to anyone in the Galaxy. A sufficiently advanced civilisation may have placed material in orbit around this black hole to study it, extractRead More →

Cloud Atlas: Rotational Spectral Modulations and potential Sulfide Clouds in the Planetary-mass, Late T-type Companion Ross 458C. (arXiv:1903.10702v1 [astro-ph.SR]) <a href="http://arxiv.org/find/astro-ph/1/au:+Manjavacas_E/0/1/0/all/0/1">Elena Manjavacas</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Apai_D/0/1/0/all/0/1">Daniel Apai</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lew_B/0/1/0/all/0/1">Ben W. P. Lew</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zhou_Y/0/1/0/all/0/1">Yifan Zhou</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Schneider_G/0/1/0/all/0/1">Glenn Schneider</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:+Karalidi_T/0/1/0/all/0/1">Theodora Karalidi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Miles_Paez_P/0/1/0/all/0/1">Paulo A. Miles-Paez</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lowrance_P/0/1/0/all/0/1">Patrick J. Lowrance</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cowan_N/0/1/0/all/0/1">Nicolas Cowan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bedin_L/0/1/0/all/0/1">Luigi R. Bedin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Marley_M/0/1/0/all/0/1">Mark S. Marley</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Metchev_S/0/1/0/all/0/1">Stan Metchev</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Radigan_J/0/1/0/all/0/1">Jacqueline Radigan</a> Measurements of photometric variability at different wavelengths provide insights into the vertical cloud structure of brown dwarfs and planetary-mass objects. In seven Hubble Space Telescope consecutive orbits, spanning $sim$10 h of observing time}, we obtained time-resolved spectroscopyRead More →

Can the long-term hemispheric asymmetry of solar activity result from fluctuations in dynamo parameters?. (arXiv:1903.10707v1 [astro-ph.SR]) <a href="http://arxiv.org/find/astro-ph/1/au:+Nepomnyashchikh_A/0/1/0/all/0/1">Alexander Nepomnyashchikh</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mandal_S/0/1/0/all/0/1">Sudip Mandal</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Banerjee_D/0/1/0/all/0/1">Dipankar Banerjee</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kitchatinov_L/0/1/0/all/0/1">Leonid Kitchatinov</a> The hemispheric asymmetry of sunspot activity observed possesses a regular component varying on a time scale of several solar cycles whose origin and properties are currently debated. This paper addresses the question of whether the long-term hemispheric asymmetry can result from random variations of solar dynamo parameters in time and latitude. Scatter in the observed tilt angles of sunspot groups is estimated to infer constraints on fluctuations in the dynamo mechanism for poloidal field regeneration. A dynamoRead More →

Hot accretion flow around neutron stars. (arXiv:1903.10708v1 [astro-ph.HE]) <a href="http://arxiv.org/find/astro-ph/1/au:+Bu_D/0/1/0/all/0/1">De-Fu Bu</a> (SHAO), <a href="http://arxiv.org/find/astro-ph/1/au:+Qiao_E/0/1/0/all/0/1">Er-Lin Qiao</a> (NAOC), <a href="http://arxiv.org/find/astro-ph/1/au:+Yang_X/0/1/0/all/0/1">Xiao-Hong Yang</a> (CQU) We perform as the first time hydrodynamic simulations to study the properties of hot accretion flow (HAF) around a neutron star (NS). The energy carried by the HAF will eventually be radiated out at the surface of the NS. The emitted photons can propagate inside the HAF and cool the HAF via Comptonization. We find that the Compton cooling can affect the properties of HAF around a NS significantly. We define the Eddington accretion rate as $dot M_{rm Edd}=10L_{rm Edd}/c^2$, with $L_{rm Edd}$ and $c$Read More →

Modification of Nanodiamonds by Xenon Implantation: A Molecular Dynamics Study. (arXiv:1903.10711v1 [cond-mat.mtrl-sci]) <a href="http://arxiv.org/find/cond-mat/1/au:+Fogg_J/0/1/0/all/0/1">Jason L. Fogg</a>, <a href="http://arxiv.org/find/cond-mat/1/au:+Aghajamali_A/0/1/0/all/0/1">Alireza Aghajamali</a>, <a href="http://arxiv.org/find/cond-mat/1/au:+Hinks_J/0/1/0/all/0/1">Jonathan A. Hinks</a>, <a href="http://arxiv.org/find/cond-mat/1/au:+Donnelly_S/0/1/0/all/0/1">Stephen E. Donnelly</a>, <a href="http://arxiv.org/find/cond-mat/1/au:+Shiryaev_A/0/1/0/all/0/1">Andrey A. Shiryaev</a>, <a href="http://arxiv.org/find/cond-mat/1/au:+Marks_N/0/1/0/all/0/1">Nigel A. Marks</a> Xenon implantation into nanodiamonds is studied using molecular dynamics. The nanodiamonds range in size from 2-10 nm and the primary knock-on (PKA) energy extends up to 40 keV. For small nanodiamonds an energy-window effect occurs in which PKA energies of around 6 keV destroy the nanodiamond, while in larger nanodiamonds the radiation cascade is increasingly similar to those in bulk material. Destruction of the small nanodiamonds occurs due to thermalRead More →

Cosmological constraints on sterile neutrino Dark Matter production mechanisms. (arXiv:1903.10712v1 [astro-ph.CO]) <a href="http://arxiv.org/find/astro-ph/1/au:+Popa_L/0/1/0/all/0/1">Lucia A. Popa</a> (Institute of Space Science (ISS), Bucharest) Presently, the constraints on the scalar neutrino DM resonant production (RP) and scalar decay production (SDP) mechanisms are based on the power suppression of the gravitational clustering at small scales, dominated by non-linear effects. These constraints are in general obtained in the linear theory under the assumption that sterile neutrinos are all of the DM. In this paper, we analysed the validity of those scenarios through their impact on the acoustic scales, the small scale fluctuations and the low-redshift geometric observables, probes that areRead More →

Inverse magnetic energy cascades embedded in magnetohydrodynamical turbulence. (arXiv:1903.10725v1 [physics.flu-dyn]) <a href="http://arxiv.org/find/physics/1/au:+Rathmann_N/0/1/0/all/0/1">Nicholas Rathmann</a>, <a href="http://arxiv.org/find/physics/1/au:+Ditlevsen_P/0/1/0/all/0/1">Peter Ditlevsen</a> The existence of partially conserved enstrophy-like quantities is conjectured to cause embedded, inverse magnetic energy cascades to develop in magnetohydrodynamical (MHD) turbulence. By decomposing the velocity and magnetic fields in spectral space onto helical modes, we show that two new quantities exist which are partially conserved among a set of three-wave (triad) interactions in MHD turbulence. In a subset of these helical triad interactions, the quantities become enstrophy-like, which, by analogy to enstrophy-conserving triad interactions in two-dimensional, nonconducting hydrodynamical turbulence, are conjectured to cause embedded, inverse magnetic energy cascadesRead More →

Towards a better coordination of Multimessenger observations: VO and future developments. (arXiv:1903.10732v1 [astro-ph.IM]) <a href="http://arxiv.org/find/astro-ph/1/au:+Ness_J/0/1/0/all/0/1">J.-U. Ness</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fernandez_C/0/1/0/all/0/1">C. S&#xe1;nchez Fern&#xe1;ndez</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ibarra_A/0/1/0/all/0/1">A. Ibarra</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Saxton_R/0/1/0/all/0/1">R. Saxton</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Salgado_J/0/1/0/all/0/1">J. Salgado</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kuulkers_E/0/1/0/all/0/1">E. Kuulkers</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kretschmar_P/0/1/0/all/0/1">P. Kretschmar</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ehle_M/0/1/0/all/0/1">M. Ehle</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Salazar_E/0/1/0/all/0/1">E. Salazar</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gabriel_C/0/1/0/all/0/1">C. Gabriel</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Perdikeas_M/0/1/0/all/0/1">M. Perdikeas</a> Context. Towards the multimessenger era, the scientific demand for simultaneous observations with different facilities is continuously increasing. The main challenges of coordinating observations is the determination of common visibility and respective scheduling constraints to find common free slots. While all this information is publicly available via the respective observatory web pages, it is cumbersome to find this informationRead More →

On the structure of galactic halos and the microwave temperature maps. (arXiv:1903.10757v1 [astro-ph.GA]) <a href="http://arxiv.org/find/astro-ph/1/au:+Amekhyan_A/0/1/0/all/0/1">A.Amekhyan</a> The study of Planck microwave temperature maps towards several nearby spiral edge-on galaxies had revealed frequency independent temperature asymmetry of Doppler origin in their halos. On an example of M31, as of relatively detailed studied galaxy, the contribution of the dust component in that effect is studied using the models of dust emission and the phenomenological profiles of the dark matter configurations. The results are in accordance with those obtained from the microwave temperature asymmetry data, thus indicating the possible contribution of dust among other radiation mechanisms in revealing theRead More →

Growth index of matter perturbations in the light of Dark Energy Survey. (arXiv:1903.10758v1 [astro-ph.CO]) <a href="http://arxiv.org/find/astro-ph/1/au:+Basilakos_S/0/1/0/all/0/1">Spyros Basilakos</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Anagnostopoulos_F/0/1/0/all/0/1">Fotios K. Anagnostopoulos</a> We study how the cosmological constraints from growth data are improved by including the measurements of bias from Dark Energy Survey (DES). In particular, we utilize the biasing properties of the DES Luminous Red Galaxies (LRGs) and the growth data provided by the various galaxy surveys in order to constrain the growth index ($gamma$) of the linear matter perturbations. Considering a constant growth index we can put tight constraints, up to $sim 10%$ accuracy, on $gamma$. Specifically, using the priors of the Dark EnergyRead More →