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The hot component of the circum-galactic medium (CGM) around star forming galaxies is detected as diffuse X-ray emission. The X-ray spectra from the CGM depend on the temperature and metallicity of the emitting plasma, providing important…

Astrophysics of Galaxies · Physics 2021-12-08 Aditi Vijayan , Miao Li

Using simultaneous multi-filter observations during the transit of an exoplanet around a K dwarf star, we determine the temperature of a starspot through modeling the radius and position with wavelength-dependent spot contrasts. We model…

The nature of the interaction between low-excitation gas filaments at ~10^4 K, seen in optical line emission, and diffuse X-ray emitting coronal gas at ~10^7 K in the centers of galaxy clusters remains a puzzle. The presence of a strong,…

We present a pulsar-atmosphere (PA) model for modulated thermal X-ray emission from cooling magnetized neutron stars. The model synthesizes the spectral properties of detailed stellar atmosphere calculations with the non-uniform surface…

Astrophysics · Physics 2007-05-23 D. A. Lloyd , R. Perna , P. Slane , F. Nicastro , L. Hernquist

We analysed red giant branch stars in 16 Galactic globular clusters, computing their atmospheric parameters both from the photometry and from excitation and ionisation balances. The spectroscopic parameters are lower than the photometric…

Solar and Stellar Astrophysics · Physics 2020-08-26 A. Mucciarelli , P. Bonifacio

(abridged) The polarized thermal radiation at far infrared and submillimeter wavelengths from dust grains in interstellar clouds with irregular magnetic fields is simulated. We show that the polarization properties of quiescent clouds and…

Astrophysics · Physics 2009-11-10 D. S. Wiebe , W. D. Watson

Semi-analytic models of galaxy formation postulate the existence of virialized gaseous halos around galaxies at high redshifts. A small fraction of the light emitted by any high-redshift quasar is therefore expected to scatter off the free…

Astrophysics · Physics 2009-10-30 Abraham Loeb

The non-spherically symmetric transport equations and exact thermal evolution model are used to calculate the transient thermal response to pulsars. The three possible ways of energy release originated from glitches, namely the `shell',…

Astrophysics · Physics 2009-10-31 Anisia P. S. Tang , K. S. Cheng

The energy source powering the X-ray emission from anomalous X-ray pulsars (AXPs) and soft gamma-ray repeaters (SGRs) is still uncertain. In one scenario, the presence of an ultramagnetized neutron star, or ``magnetar'', with B on the order…

Astrophysics · Physics 2009-11-06 Rosalba Perna , Jeremy Heyl , Lars Hernquist , Adrienne Juett , Deepto Chakrabarty

We propose a vacuum gap (VG) model which can be applied uniformly for normal and high magnetic field pulsars. The model requires strong and non-dipolar surface magnetic field near the pulsar polar cap. We assume that the actual surface…

Astrophysics · Physics 2009-11-07 Janusz A. Gil , George I. Melikidze , Dipanjan Mitra

Thermal emission from the surface of an ultramagnetic neutron star is believed to contribute significantly to the soft X-ray flux of the Anomalous X-ray Pulsars. We compare the detailed predictions of models of the surface emission from a…

Astrophysics · Physics 2009-11-06 Feryal Ozel , Dimitrios Psaltis , Victoria M. Kaspi

Current and future imaging surveys will measure cosmic shear with a statistical precision that demands a deeper understanding of potential systematic biases in galaxy shape measurements than has been achieved to date. We investigate the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-18 J. E. Meyers , P. R. Burchat

As is known, resonant scattering can distort the surface-brightness profiles of clusters of galaxies in X-ray lines. We demonstrate that the scattered line emission should be polarized and possibly detectable with near-future X-ray…

Astrophysics · Physics 2009-11-07 S. Sazonov , E. Churazov , R. Sunyaev

Observations in the Mg XII 8.42 AA line onboard the CORONAS-F satellite have revealed compact high temperature objects-hot X-ray points (HXP)-and their major physical parameters were investigated. Time dependencies of temperature, emission…

Solar and Stellar Astrophysics · Physics 2015-09-25 Anton Reva , Sergey Shestov , Sergey Bogachev , Sergey Kuzin

An atlas of gas temperature maps is presented for a flux limited catalog of galaxy clusters. The sample of clusters is based on the Edge et al. (1990) sample, with the inclusion of five additional clusters, all with fluxes f_X(2-10 keV)>=…

Astrophysics · Physics 2007-05-23 R. Hank Donnelly , C. Jones , W. Forman , E. Churazov , M. Gilfanov

Observations and numerical simulations have shown that the relation between the mass scaled with the critical density of the universe and the X-ray temperature of galaxy clusters is approximately represented by $M_\Delta \propto T_X^{3/2}$…

Astrophysics of Galaxies · Physics 2018-08-15 Yutaka Fujita , Keiichi Umetsu , Stefano Ettori , Elena Rasia , Nobuhiro Okabe , Massimo Meneghetti

We present a model of thermal X-ray emission from hot spots on the surface of a rotating compact star with an unmagnetized light-element atmosphere. An application to ROSAT, Chandra, and XMM-Newton X-ray observations of the nearest known…

Astrophysics · Physics 2009-11-11 Slavko Bogdanov , George B. Rybicki , Jonathan E. Grindlay

In the advent of next generation gamma-ray missions, we present general properties of spectral features of high-energy emission above $1\MeV$ expected for a class of millisecond, low magnetic field ($\sim 10^9\G$) pulsars. We extend…

Astrophysics · Physics 2009-10-31 T. Bulik , B. Rudak , J. Dyks

Current models of pulsar gamma-ray emission use the magnetic field of a rotating dipole in vacuum as a first approximation to the shape of plasma-filled pulsar magnetosphere. In this paper we revisit the question of gamma-ray light-curve…

High Energy Astrophysical Phenomena · Physics 2014-11-20 Xue-Ning Bai , Anatoly Spitkovsky

Using Monte Carlo simulations, we study the character of the spin-glass (SG) state of a site-diluted dipolar Ising model. We consider systems of dipoles randomly placed on a fraction x of all L^3 sites of a simple cubic lattice that point…

Statistical Mechanics · Physics 2015-03-13 Juan J. Alonso