Related papers: gamma Cassiopeiae: an X-ray Be star with personali…
We examine the X-ray spectra and variability of the sample of X-ray sources with L_X = 10^{31}-10^{33} erg s^{-1} identified within the inner 9' of the Galaxy. Very few of the sources exhibit intra-day or inter-month variations. We find…
We present an analysis of a series of four consecutive Chandra high resolution transmission gratings observations, amounting to a total of 150 ks, of the Be X-ray source HD119682 (= 1WGA J1346.5-6255), a member of the new class of gamma Cas…
Compact Symmetric Objects (CSOs) are a distinct category of jetted active galactic nuclei whose high-energy emission is not well understood. We examined the X-ray characteristics of 17 bona fide CSOs using observations from Chandra,…
Hard X- and $\gamma$-ray spectra and light curves resulting from radioactive decays are computed for aspherical (jet-like) and energetic supernova models (representing a prototypical hypernova SN 1998bw), using a 3D energy- and…
We have detected diffuse soft X-ray emission (0.4-1 keV) from the disk of the spiral galaxy NGC 2403 with Chandra. This diffuse emission (with a total luminosity of 2.1 x 10^38 erg/s and a gas temperature of 2-8 x 10^6 K) is well separated…
We report on observations of very high-energy gamma rays from the shell-type supernova remnant Cassiopeia A with the VERITAS stereoscopic array of four imaging atmospheric Cherenkov telescopes in Arizona. The total exposure time for these…
We report the localization of the forward and reversed shock fronts in the young supernova remnant Cas-A using X-ray data obtained with the Chandra Observatory. High resolution X-ray maps resolve a previously unseen X-ray feature…
We present the results of a 17 ks Chandra ACIS-S observation of the nearby dwarf spiral galaxy NGC 4395. Chandra affords the first high-quality, broadband X-ray detection of the active nucleus of this object that is uncontaminated by nearby…
We present 197 ks HETG and 95 ks NuSTAR spectra of the $\gamma\,$Cas-type object V750 Ara. The high-resolution X-ray spectra show that the target is similar to other objects of this class. Data are interpreted under the assumption that the…
In photometry of $\gamma$ Cas (B0.5 IVe) from the SMEI and BRITE-Constellation satellites, indications of low-order non-radial pulsation have recently been found, which would establish an important commonality with the class of classical Be…
There has been extensive recent progress in X-ray observations of clusters of galaxies with the analysis of the entire ASCA database and recent new results from Beppo-SAX, Chandra, and XMM-Newton. The temperature profiles of most clusters…
We summarize the spectral characteristics of a sample of 22 bright gamma-ray bursts detected with the gamma-ray burst sensors aboard the satellite Ginga. This instrument employed a proportional and scintillation counter to provide…
We present a Chandra observation of the exceptional planet bearing A5V star HR 8799, more precisely classified as a kA5hF0mA5 star and search for intrinsic X-ray emission. We clearly detect HR 8799 at soft X-ray energies with the ACIS-S…
We present an 82 ksec Chandra ACIS-I observation of a large-scale hierarchical complex, which consists of various clusters/groups of galaxies and low-surface brightness X-ray emission at z = 0.247. This high-resolution {\sl Chandra}…
Analysis of Chandra observations of the neutron star (NS) in the centre of the Cassiopeia A supernova remnant taken in the subarray (FAINT) mode of the ACIS detector performed by Posselt and collaborators revealed, after inclusion of the…
We investigate the effect of the circumstellar medium density profile on the X-ray emission from outer ejecta knots in the Cassiopeia A supernova remnant using the 1 Ms Chandra observation. The spectra of a number of radial series of ejecta…
A timing analysis of VHE gamma-ray observations of Cen X-3 taken with the University of Durham Mark 6 telescope was performed, using both Rayleigh and Bayesian statistics. Data from only 1 observation produced evidence for periodicity, in a…
During 1990-92, the WATCH all-sky X-ray monitor on Granat discovered six short-duration X-ray transients. In this paper we discuss their possible relationship to peculiar stars. Only one of the fast (few hours) X-ray transients (GRS…
X-ray images of some young supernova remnants show bright point sources which have not been detected in radio, optical and gamma-ray bands. Despite the similarity of the X-ray spectra of these objects, they show a variety of temporal…
We report on observations of the supernova remnant Cassiopeia A in the energy range from 100 MeV to 100 GeV using 44 months of observations from the Large Area Telescope on board the Fermi Gamma-ray Space Telescope. We perform a detailed…