We report here the results of the first Chandra X-Ray Observatory observations of the globular cluster M28 (NGC 6626). We detect 46 X-ray sources of which 12 lie within one core radius of the center. We show that the apparently extended X-ray core emission seen with the ROSAT HRI is due to the superposition of multiple discrete sources for which we determine the X-ray luminosity function down t...

We present the results of an ongoing project to use the X-ray observations of Type Ia Supernova Remnants to constrain the physical processes involved in Type Ia Supernova explosions. We use the Tycho Supernova Remnant (SN 1572) as a benchmark case, comparing its observed spectrum with models for the X-ray emission from the shocked ejecta generated from different kinds of Type Ia explosions. Bot...

Observations have revealed strong evidence for powerful jets in the Low/Hard states of black hole candidate X-ray binaries. Correlations between the radio and IR, and radio and X-ray bands suggest that significant contributions to the observed broadband spectrum originate via synchrotron, and also possibly inverse Compton, emission from the jet. We show here that, for reasonable assumptions abo...

This paper reports on an analysis of two Chandra X-ray observations of the young magnetic B star ρ Ophiuchus S1. X-ray emission from the star was detected in both observations. The average flux was almost the same in both, but during each observation the flux showed significant time variations by a factor of two on timescales of 20–40 ks. Each spectrum could be fit by either an absorbed power-l...

We present SwiftUVOT data on the optical afterglow of the X-ray flash of 2005 April 6 (XRF 050406) from 88 to 10 s after the initial prompt -ray emission. Our observations in the V, B, and U bands are the earliest that have been taken of an XRF optical counterpart. Combining the early-time optical temporal and spectral properties with -ray and simultaneous X-ray data taken with the BATand XRT t...

LSI +61 303 is one of the few X-ray binaries with Be star companion from which both radio and high-energy gamma-ray emission have been observed. We present XMM-Newton and INTEGRAL observations which reveal variability of the X-ray spectral index of the system. The X-ray spectrum is hard (photon index Γ ≃ 1.5) during the orbital phases of both high and low X-ray flux. However, the spectrum softe...

We present the results from a Chandra observation of the powerful radio galaxy 3C 265. We detect X–ray emission from the nucleus, the radio hotspots and lobes. In particular, the lobe X–ray emission is well explained as anisotropic inverse Compton scattering of the nuclear photons by the relativistic electrons in the radio lobes; the comparison between radio synchrotron and IC emission yields a...

A short Chandra ACIS-S observation of the Seyfert 2 galaxy IC 2560, which hosts a luminous nuclear water megamaser, shows: 1) the X-ray emission is extended; 2) the X-ray spectrum shows emission features in the soft (E < 2 keV) X-ray band; this is the major component of the extended emission; and 3) a very strong (EW∼ 3.6 keV) iron Kα line at 6.4 keV on a flat continuum. This last feature clear...

We present the results from a Chandra observation of the powerful radio galaxy 3C 265. We detect X–ray emission from the nucleus, the radio hotspots and lobes. In particular, the lobe X–ray emission is well explained as anisotropic inverse Compton scattering of the nuclear photons by the relativistic electrons in the radio lobes; the comparison between radio synchrotron and IC emission yields a...

ASCA and GINGA X-ray data from the magnetic Cataclysmic Variable BY Cam show that the spectrum is strongly affected by complex absorption, probably from the pre-shock accretion column. The intrinsic emission from the shock is significantly better described by the theoretically expected multi-temperature structure rather than a single temperature plasma, but with cyclotron cooling probably suppr...