RAS_WEB (Page 4,537)

Statistical discrimination of RFI and astronomical transients in 2-bit digitized time domain signals. (arXiv:1903.00588v1 [astro-ph.IM]) <a href="http://arxiv.org/find/astro-ph/1/au:+Nita_G/0/1/0/all/0/1">Gelu M. Nita</a> (1), <a href="http://arxiv.org/find/astro-ph/1/au:+Keimpema_A/0/1/0/all/0/1">Aard Keimpema</a> (2), <a href="http://arxiv.org/find/astro-ph/1/au:+Paragi_Z/0/1/0/all/0/1">Zsolt Paragi</a> (2) ((1) Center for Solar-Terrestrial Research, New Jersey Institute of Technology, (2) Joint institute for VLBI ERIC) We investigate the performance of the generalized Spectral Kurtosis (SK) estimator in detecting and discriminating natural and artificial very short duration transients in the 2-bit sampling time domain Very-Long-Baseline Interferometry (VLBI) data. We demonstrate that, while both types of transients may be efficiently detected, their natural or artificial nature cannot be distinguished if only a time domain SK analysis is performed.Read More →

Implications of a time-varying Galactic potential for determinations of the dynamical surface density. (arXiv:1903.00607v1 [astro-ph.GA]) <a href="http://arxiv.org/find/astro-ph/1/au:+Haines_T/0/1/0/all/0/1">Tim Haines</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+DOnghia_E/0/1/0/all/0/1">Elena D&#x27;Onghia</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Famaey_B/0/1/0/all/0/1">Benoit Famaey</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Laporte_C/0/1/0/all/0/1">Chervin Laporte</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hernquist_L/0/1/0/all/0/1">Lars Hernquist</a> Recent studies have shown that the passage of a massive satellite through the disk of a spiral galaxy can induce vertical wobbles in the disk and produce features such as in-plane rings and phase-space spirals. Here we analyze a high-resolution N-body simulation of a live stellar disk perturbed by the recent passage of a massive dwarf galaxy that induces such perturbations. We study the implications of the phase-space structures for the estimate of the matterRead More →

Filtering solar-like oscillations for exoplanet detection in radial velocity observations. (arXiv:1903.00657v1 [astro-ph.SR]) <a href="http://arxiv.org/find/astro-ph/1/au:+Chaplin_W/0/1/0/all/0/1">William J. Chaplin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cegla_H/0/1/0/all/0/1">Heather M. Cegla</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Watson_C/0/1/0/all/0/1">Christopher A. Watson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Davies_G/0/1/0/all/0/1">Guy R. Davies</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ball_W/0/1/0/all/0/1">Warrick H. Ball</a> Cool main-sequence, sub-giant and red-giant stars all show solar-like oscillations, pulsations that are excited and intrinsically damped by near-surface convection. Many overtones are typically excited to observable amplitudes, giving a rich spectrum of detectable modes. These modes provide a wealth of information on fundamental stellar properties. However, the radial velocity shifts induced by these oscillations can also be problematic when searching for low-mass, long-period planets; this is because their amplitudes are large enoughRead More →

Eclipse timing variation analysis of OGLE-IV eclipsing binaries toward the Galactic Bulge. I. Hierarchical triple system candidates. (arXiv:1903.00674v1 [astro-ph.SR]) <a href="http://arxiv.org/find/astro-ph/1/au:+Hajdu_T/0/1/0/all/0/1">T. Hajdu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Borkovits_T/0/1/0/all/0/1">T. Borkovits</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Forgacs_Dajka_E/0/1/0/all/0/1">E. Forg&#xe1;cs-Dajka</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sztakovics_J/0/1/0/all/0/1">J. Sztakovics</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Marschalko_G/0/1/0/all/0/1">G. Marschalk&#xf3;</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kutrovatz_G/0/1/0/all/0/1">G. Kutrov&#xe1;tz</a> We report a study of the eclipse timing variation (ETV) of short period ($P_1le 6^d$) eclipsing binaries (EB) monitored during the photometric survey OGLE-IV. From the 425,193 EBs we selected approximately 80,000 binaries that we found suitable for further examination. Among them we identified 992 potential hierarchical triple (or multiple ) system candidates exhibiting light-travel-time effect (LTTE). Besides, we obtained the orbital parameters of these systems and carriedRead More →

MeV Dark Matter in light of the Small Scale Crisis. (arXiv:1903.00701v1 [astro-ph.CO]) <a href="http://arxiv.org/find/astro-ph/1/au:+Li_C/0/1/0/all/0/1">Changhong Li</a> The small-scale crisis, discrepancies among observations, theoretical predictions and N-body simulations on the sub-galactic scale structures, may imply a suppression of matter perturbation on small scale. In this work, we find that a novel gravitational effect originated from the non-equilibrium process of dark matter production can result in such a suppression, which may be relevant for the small-scale problems. As an illustration, we show that if the particle mass of dark matter is $m_chi=2.2~text{MeV}$, the suppression takes place at $1~text{kpc}$. This new mechanism of suppression is alternative to the well-knownRead More →

The future of stellar occultations by distant solar system bodies: perspectives from the Gaia astrometry and the deep sky surveys. (arXiv:1903.00723v1 [astro-ph.EP]) <a href="http://arxiv.org/find/astro-ph/1/au:+Camargo_J/0/1/0/all/0/1">Julio Camargo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Desmars_J/0/1/0/all/0/1">Josselin Desmars</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Braga_Ribas_F/0/1/0/all/0/1">Felipe Braga-Ribas</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Vieira_Martins_R/0/1/0/all/0/1">Roberto Vieira-Martins</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Assafin_M/0/1/0/all/0/1">Marcelo Assafin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sicardy_B/0/1/0/all/0/1">Bruno Sicardy</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Berard_D/0/1/0/all/0/1">Diane B&#xe9;rard</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Benedetti_Rossi_G/0/1/0/all/0/1">Gustavo Benedetti-Rossi</a> Distant objects in the solar system are crucial to better understand the history and evolution of its outskirts. The stellar occultation technique allows the determination of their sizes and shapes with kilometric accuracy, a detailed investigation of their immediate vicinities, as well as the detection of tenuous atmospheres. The prediction of such events is a key point in thisRead More →

Tesseral harmonics of Jupiter from static tidal response. (arXiv:1903.00749v1 [astro-ph.EP]) <a href="http://arxiv.org/find/astro-ph/1/au:+Nettelmann_N/0/1/0/all/0/1">Nadine Nettelmann</a> The Juno Orbiter is measuring the three-dimensional gravity field perturbation of Jupiter induced by its rapid rotation, zonal flows, and tidal response to its major natural satellites. This paper aims to provide the contributions to the tesseral harmonics coefficients Cnm, Snm, and the Love numbers knm to be expected from static tidal response in the gravity field of rotating Jupiter. For that purpose, we apply the method of Concentric Maclaurin Ellipsoids (CMS). As we are interested in the variation of the tidal potential with the longitudes of the moons, we take intoRead More →

Genus Statistic Applied to the X-ray Remnant of SN 1572: Clues to the Clumpy Ejecta Structure of Type Ia Supernovae. (arXiv:1903.00764v1 [astro-ph.HE]) <a href="http://arxiv.org/find/astro-ph/1/au:+Sato_T/0/1/0/all/0/1">Toshiki Sato</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hughes_J/0/1/0/all/0/1">John P. Hughes</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Williams_B/0/1/0/all/0/1">Brian J. Williams</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Morii_M/0/1/0/all/0/1">Mikio Morii</a> Clumpy structures are a common feature in X-ray images of young Type Ia supernova remnants (SNRs). Although the precise origin of such clumps remains unclear there are three generic possibilities: clumpiness imposed during the explosion, hydrodynamic instabilities that act during the remnant’s evolution, and pre-existing structures in the ambient medium. In this article we focus on discriminating between clumping distributions that arise from the explosion and those from theRead More →

High-speed Ejecta from the Gamma-ray Binary PSR B1259-63/LS 2883. (arXiv:1903.00781v1 [astro-ph.HE]) <a href="http://arxiv.org/find/astro-ph/1/au:+Pavlov_G/0/1/0/all/0/1">George G. Pavlov</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hare_J/0/1/0/all/0/1">Jeremy Hare</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kargaltsev_O/0/1/0/all/0/1">Oleg Kargaltsev</a> Observing the famous high-mass, eccentric X-ray and gamma-ray binary PSR B1259-63/LS 2883 with Chandra, we detected X-ray emitting clumps moving from the binary with speeds of about 0.1 of the speed of light, possibly with acceleration. The clumps are being ejected at least once per binary period, 3.4 years, presumably around binary periastrons. The power-law spectra of the clumps can be interpreted as synchrotron emission of relativistic electrons. Here we report the results of 8 observations of the clumps in 2011-2017 (two binary cycles)Read More →

Investigating state transition luminosities of Galactic black hole transients in the outburst decay. (arXiv:1903.00837v1 [astro-ph.HE]) <a href="http://arxiv.org/find/astro-ph/1/au:+Motlagh_A/0/1/0/all/0/1">Armin Vahdat Motlagh</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kalemci_E/0/1/0/all/0/1">Emrah Kalemci</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Maccarone_T/0/1/0/all/0/1">Thomas J. Maccarone</a> We have performed a comprehensive spectral and timing analyses of Galactic black hole transients (GBHTs) during outburst decay in order to obtain the distribution of state transition luminosities. Using the archival data of the Rossi X-ray Timing Explorer (RXTE), we have calculated the weighted mean for state transition luminosities of 11 BH sources in 19 different outbursts and for disk and power-law luminosities separately. We also produced histograms of these luminosities in terms of Eddington luminosity fraction (ELF) andRead More →

Gaussian Processes, Median Statistics, Milky Way Rotation Curves. (arXiv:1903.00892v1 [astro-ph.GA]) <a href="http://arxiv.org/find/astro-ph/1/au:+Yu_H/0/1/0/all/0/1">Hai Yu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Singal_A/0/1/0/all/0/1">Aman Singal</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Peyton1z_J/0/1/0/all/0/1">Jacob Peyton1z</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Crandall_S/0/1/0/all/0/1">Sara Crandall</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ratra_B/0/1/0/all/0/1">Bharat Ratra</a> We use the Iocco et al. (2015) compilation of 2,780 circular velocity measurements to analyze the Milky Way rotation curve. We find that the error bars for individual measurements are non-gaussian, and hence instead derive median statistics binned central circular velocity values and error bars from these data. We use these median statistics central values and error bars to fit the data to simple, few parameter, rotation curve functions. These simple functions are unable to adequately capture the significant smallRead More →

Atmospheres on Nonsynchronized Eccentric-tilted Exoplanets I: Dynamical Regimes. (arXiv:1903.00907v1 [astro-ph.EP]) <a href="http://arxiv.org/find/astro-ph/1/au:+Ohno_K/0/1/0/all/0/1">Kazumasa Ohno</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zhang_X/0/1/0/all/0/1">Xi Zhang</a> Relatively long-period nonsynchronized planets—such as warm Jupiters—potentially retain the primordial rotation, eccentricity, and obliquity that might encapsulate information on planetary climate and formation processes. To date, there has not been a systematic study on climate patterns on these planets that will significantly influence their observations. Here we investigate the atmospheric dynamics of nonsynchronized, fast-rotating exoplanets across various radiative timescales, eccentricities, and obliquities using a shallow water model. The dynamical pattern can be demarcated into five regimes in terms of radiative timescale $tau_{rm rad}$ and obliquity ${theta}$. An atmosphere withRead More →

Atmospheres on Nonsynchronized Eccentric-tilted Exoplanets II: Thermal Light Curves. (arXiv:1903.00908v1 [astro-ph.EP]) <a href="http://arxiv.org/find/astro-ph/1/au:+Ohno_K/0/1/0/all/0/1">Kazumasa Ohno</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zhang_X/0/1/0/all/0/1">Xi Zhang</a> Thermal light-curve analysis is a powerful approach to probe the thermal structures of exoplanetary atmospheres, which are greatly influenced by the planetary obliquity and eccentricity. Here we investigate the thermal light curves of eccentric-tilted exoplanets across various radiative timescales, eccentricities, obliquities, and viewing geometries using results of shallow-water simulations presented in Ohno $&$ Zhang (2019). We also achieve an analytical theory of the thermal light curve that can explain general trends in the light curves of tilted exoplanets. For tilted planets in circular orbits, the orbital phase ofRead More →

Origins Space Telescope: predictions for far-IR spectroscopic surveys. (arXiv:1903.00946v1 [astro-ph.GA]) <a href="http://arxiv.org/find/astro-ph/1/au:+Bonato_M/0/1/0/all/0/1">Matteo Bonato</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zotti_G/0/1/0/all/0/1">Gianfranco De Zotti</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Leisawitz_D/0/1/0/all/0/1">David Leisawitz</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Negrello_M/0/1/0/all/0/1">Mattia Negrello</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Massardi_M/0/1/0/all/0/1">Marcella Massardi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Baronchelli_I/0/1/0/all/0/1">Ivano Baronchelli</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cai_Z/0/1/0/all/0/1">Zhen-Yi Cai</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bradford_C/0/1/0/all/0/1">Charles M. Bradford</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pope_A/0/1/0/all/0/1">Alexandra Pope</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Murphy_E/0/1/0/all/0/1">Eric J. Murphy</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Armus_L/0/1/0/all/0/1">Lee Armus</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cooray_A/0/1/0/all/0/1">Asantha Cooray</a> We illustrate the extraordinary potential of the (far-IR) Origins Survey Spectrometer (OSS) on board the Origins Space Telescope (OST) to address a variety of open issues on the co-evolution of galaxies and AGNs. We present predictions for blind surveys, each of 1000 h, with different mapped areas (a shallow survey covering an area of 10 deg$^{2}$Read More →

The Global Star-Formation Law by Supernova Feedback. (arXiv:1903.00962v1 [astro-ph.GA]) <a href="http://arxiv.org/find/astro-ph/1/au:+Dekel_A/0/1/0/all/0/1">Avishai Dekel</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sarkar_K/0/1/0/all/0/1">Kartick C. Sarkar</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Jiang_F/0/1/0/all/0/1">Fangzhou Jiang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bournaud_F/0/1/0/all/0/1">Frederic Bournaud</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Krumholz_M/0/1/0/all/0/1">Mark R. Krumholz</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ceverino_D/0/1/0/all/0/1">Daniel Ceverino</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Primack_J/0/1/0/all/0/1">Joel R. Primack</a> We address a simple model where the Kennicutt-Schmidt (KS) relation between the macroscopic densities of star-formation rate (SFR, $rho_{rm sfr}$) and gas ($n$) in galactic discs emerges from self-regulation of the SFR via supernova feedback. It arises from the physics of supernova bubbles, insensitive to the microscopic SFR recipe and not explicitly dependent on gravity. The key is that the filling factor of SFR-suppressed supernova bubbles self-regulates to a constant, $fsim 0.5$.Read More →

Improving Constraints on Fundamental Physics Parameters with the Clustering of Sunyaev-Zeldovich Selected Galaxy Clusters. (arXiv:1903.00976v1 [astro-ph.CO]) <a href="http://arxiv.org/find/astro-ph/1/au:+Cromer_D/0/1/0/all/0/1">Dylan Cromer</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Battaglia_N/0/1/0/all/0/1">Nicholas Battaglia</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Madhavacheril_M/0/1/0/all/0/1">Mathew S. Madhavacheril</a> Upcoming millimeter experiments that probe the cosmic microwave background (CMB) will observe tens of thousands of galaxy clusters through the thermal Sunyaev-Zeldovich (tSZ) effect. tSZ selected clusters are powerful probes of cosmological models, as they trace the late-time growth of structure. Late-time structure growth is highly sensitive to extensions to the standard cosmological model ($Lambda$CDM), such as the sum of the neutrino masses, the dark energy equation of state, and modifications to general relativity. The nominal statistic used forRead More →

Theoretical model of HD 163296 presently forming in-situ planets and comparison with the models of AS 209, HL Tau, and TW Hya. (arXiv:1903.01019v1 [astro-ph.EP]) <a href="http://arxiv.org/find/astro-ph/1/au:+Christodoulou_D/0/1/0/all/0/1">Dimitris M. Christodoulou</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kazanas_D/0/1/0/all/0/1">Demosthenes Kazanas</a> We fit an isothermal oscillatory density model to the disk of HD 163296 in which planets have presumably already formed and they are orbiting at least within the four observed dark gaps. This 156 AU large axisymmetric disk shows various physical properties comparable to those of AS 209, HL Tau, and TW Hya that we have modeled previously; but it compares best to AS 209. The disks of HD 163296 and AS 209 areRead More →

Observational Constraints on the Rastall gravity from Rotation Curves of Low Surface Brightness Galaxies. (arXiv:1903.01034v1 [astro-ph.GA]) <a href="http://arxiv.org/find/astro-ph/1/au:+Tang_M/0/1/0/all/0/1">Meirong Tang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Xu_Z/0/1/0/all/0/1">Zhaoyi Xu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wang_J/0/1/0/all/0/1">Jiancheng Wang</a> The Rastall gravity is a modification of Einstein’s general relativity, in which the energy-momentum conservation is not satisfied and depends on the gradient of the Ricci curvature. It is in dispute whether the Rastall gravity is equivalent to the general relativity (GR). In this work, we constrain the theory using the rotation curves of Low Surface Brightness (LSB) spiral galaxies. Through fitting the rotation curves of LSB galaxies, we obtain the parameter $beta$ of the Rastall gravity. The $beta$ valuesRead More →

Initial data for general relativistic simulations of multiple electrically charged black holes with linear and angular momenta. (arXiv:1903.01036v1 [gr-qc]) <a href="http://arxiv.org/find/gr-qc/1/au:+Bozzola_G/0/1/0/all/0/1">Gabriele Bozzola</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Paschalidis_V/0/1/0/all/0/1">Vasileios Paschalidis</a> A general relativistic, stationary and axisymmetric black hole in a four-dimensional asymptotically-flat spacetime is fully determined by its mass, angular momentum and electric charge. The expectation that astrophysically relevant black holes do not posses charge has resulted in a limited number of investigations of moving and charged black holes in the dynamical, strong-field gravitational (and electromagnetic) regime, where numerical studies are necessary. Apart from having a theoretical interest, the advent of multimessenger astronomy with gravitational waves offers new ways toRead More →

The flare catalog and the flare activity in the Kepler mission. (arXiv:1903.01056v1 [astro-ph.SR]) <a href="http://arxiv.org/find/astro-ph/1/au:+Yang_H/0/1/0/all/0/1">Huiqin Yang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Liu_J/0/1/0/all/0/1">Jifeng Liu</a> We present a flare catalog of the {it Kepler} mission using the long-cadence data of Data Release 25. This catalog comprises 3420 flare stars and 162,262 flare events. A comparison shows that the flare catalogs of previous studies are seriously polluted by various false positive signals and artifacts. The incidence of flare stars rises with decreasing temperature, which accords with the theoretical analysis. The flare frequency distributions (FFDs) from F-type stars to M-type stars obey a power-law relation with $alpha sim 2$, indicating that they haveRead More →