Related papers: Bulk Compton motion in the luminous quasar 4C04.42…

We report the results of XMM-Newton observations of the X-ray bright, radio-loud blazar GB B1428+4217 at a redshift of z=4.72. We confirm the presence of soft X-ray spectral flattening at energies <0.7 keV as reported in previous ROSAT and…

Context. On the basis of XMM-Newton observations, we investigate the energy balance of selected magnetic cataclysmic variables, which have shown an extreme soft-to-hard X-ray flux ratio in the ROSAT All-Sky Survey. Aims. We intend to…

We study spectra generated by Comptonization of soft photons by cold electrons radially free-falling onto a black hole. We use a Monte Carlo method involving a fully relativistic description of Comptonization in the Kerr space-time. In…

BeppoSAX observed the Seyfert 1 galaxy NGC 3783 for ~ 5 days from 1998 June 6 to 1998 June 10. The average flux during the observation was F(2-10 keV) ~ 6 X 10^{-11} erg cm^-2 s^-1. The long exposure provided a very high quality spectrum…

We present sensitive, high-resolution, X-ray imaging from Chandra of the high-redshift radio galaxy 4C 41.17 (z=3.8). Our 150-ks Chandra exposure detects strong X-ray emission from a point source coincident with the nucleus of the radio…

We present detailed spectral and temporal characteristics both in the hard X-ray (>10 keV) and soft X-ray (<10 keV) domains, obtained using data from INTEGRAL, XMM-Newton, ASCA and RXTE. The INTEGRAL time-averaged total spectrum shows a…

We report on the first observation of the Seyfert 1 galaxy NGC4593 in the 0.1-200 keV band, performed with the BeppoSAX observatory. Its spectral components are for the first time simultaneously measured: a power-law with photon spectral…

The XMM-Newton observation of the nearby FR-II radio galaxy 3C 98 is reported. In two exposures on the target, faint diffuse X-ray emission associated with the radio lobes was significantly detected, together with a bright X-ray active…

Powerful quasars and radio galaxies are injecting large amounts of energy in the form of radio plasma into the inter-galactic medium (IGM). Once this nonthermal component of the IGM has radiatively cooled the remaining radio emission is…

The soft X-ray excess in the spectra of active galactic nuclei is characterized by similar electron temperatures of 0.1 -- 0.3 keV and similar photon indices around 2.2 -- 3, if fitted with inverse Comptonization. It remains a puzzle why…

The X-ray luminous quasar GB 1428+4217 at redshift 4.72 has been observed with ASCA. The observed 0.5-10 keV flux is 3.2E-12 erg/s/cm2. We report here on the intrinsic 4-57 keV X-ray spectrum, which is very flat (photon index of 1.29). We…

The extended high-energy gamma-ray (>100 MeV) emission occurring after the prompt gamma-ray bursts (GRBs) is usually characterized by a single power-law spectrum, which has been explained as the afterglow synchrotron radiation. We report on…

We present a detailed analysis of XMM-Newton EPIC-pn data for the Seyfert-1 galaxy NGC 4593. We discuss the X-ray spectral properties of this source as well as its variations with time. The 0.5-10 keV spectrum shows significant complexity…

Using Monte Carlo methods to simulate the inverse Compton scattering of soft photons, we model the spectrum of the Galactic black hole candidate Cyg X-1, which shows evidence of a nonthermal tail extending beyond a few hundred keV. We…

We present the analysis of a new broad-band X-ray spectrum (0.6-180.0 keV) of the radio-quiet quasar MR 2251-178 which uses data obtained with both Suzaku and the Swift/BAT. In accordance with previous observations, we find that the general…

A BeppoSAX observation of the z=2.34 quasar PKS2149-306 produced a strong signal in the high energy PDS instrument up to a maximum observed energy of nearly 50 keV, 150 keV in the quasar frame. The Beppo-SAX spectrum spans almost 3 decades…

We present an analysis of the spectral properties of the peculiar X-ray pulsar X Per based on INTEGRAL observations. We show that the source exhibits an unusually hard spectrum and is confidently detected by ISGRI up to more than 100 keV.…

We study X-ray and soft gamma-ray spectral properties of BLRGs using data from Ginga, ASCA, OSSE and EXOSAT. The X-ray spectra are well fitted by an intrinsic power-law continuum with an energy index of alpha ~ 0.7, moderately absorbed by a…

We present the results of simultaneous XMM-Newton and RXTE observations of the Broad-Line Radio Galaxy 3C 111. We find that the Compton reflection bump is extremely weak, however, broad residuals are clearly present in the spectrum near the…

We present results from a half-day observation by XMM-Newton of the nucleus of the nearby Seyfert 2 galaxy NGC 6300. The X-ray spectrum of the nucleus consists of a heavily absorbed hard component dominating the 3--10 keV band and a soft…