We report on the progress of our search for serendipitous distant X-ray galaxy clusters in the ROSAT PSPC pointed observations archive. The initial aim of our work is to measure the X-ray luminosity function of clusters down to f lim = 4×10 −14 erg cm −2 s −1 and so test the claims of cluster evolution at moderate redshifts. We have R band images and spectroscopy for 45 extended sources detecte...

We have extended the spectral modelling of the soft X-ray background (SXRB) using the ROSAT PSPC data along several lines of galactic longitude. Our results continue to demonstrate the need for a Galactic halo component, which is shown to vary markedly as a function of position. These fluctuations significantly affect the ability to investigate variations in the extragalactic SXRB below 2 keV. ...

A search was conducted for a hot intragroup medium in 109 low-redshift galaxy groups observed with the ROSAT PSPC. Evidence for diffuse, extended X-ray emission is found in at least 61 groups. Approximately one-third of these detections have not been previously reported in the literature. Most of the groups are detected out to less than half of the virial radius with ROSAT. Although some spiral...

I present 1.5and 8.4-GHz observations with all configurations of the NRAO VLA of the wide-angle tail source 3C 130. The source has a pair of relatively symmetrical, wellcollimated inner jets, one of which terminates in a compact hot spot. Archival ROSAT PSPC data confirm that 3C 130’s environment is a luminous cluster with little sign of sub-structure in the X-ray-emitting plasma. I compare the...

We present ROSAT PSPC and HRI observations of the distant cluster A 1300 (z = 0.3071) in conjunction with optical data, to investigate the physics of the intra-cluster medium and the dynamical state of the cluster. By means of a multi-resolution wavelet analysis, we find evidence for structures in the X-ray emission of this very luminous (LX ∼ 1.7×1045 erg s−1 in the 0.1–2.4 keVband) andmassive...

We have made ROSAT PSPC and HRI X-ray observations to study the intracluster gas surrounding the powerful radio source Hercules A. The cluster is luminous in X-rays (Lbol = 4.8 × 10 37 W), although apparently poor in optical galaxies, and the host of the radio source is the central dominating galaxy of the cluster. The azimuthally-averaged X-ray surface brightness profile is well fitted by a mo...

We present the results of a systematic search for Xray flares on young stars observed during ROSAT PSPC observations of the Taurus-Auriga-Perseus sky region. All pointed PSPC observations currently available from the ROSAT Public Data Archive with known pre-main sequence T Tauri Stars or young Pleiads or Hyads in the field of view are analyzed. A study of the activity of late-type stars of diff...

We present the results of a systematic search for Xray flares on young stars observed during ROSAT PSPC observations of the Taurus-Auriga-Perseus sky region. All pointed PSPC observations currently available from the ROSAT Public Data Archive with known pre-main sequence T Tauri Stars or young Pleiads or Hyads in the field of view are analyzed. A study of the activity of late-type stars of diff...

We report the serendipitous detection of a previously unreported pulsar from the direction of the Small Magellanic Cloud using data from the CHANDRA X-Ray Observatory. Because of its luminosity (∼ 1.5× 10 ergs/s), its near lack of variability for more than 20 years, and its soft spectrum we propose that it is an anomalous X-ray pulsar (AXP). Data from the ROSAT PSPC in conjunction with the CHAN...

We study the contribution of an active region and its core to the luminosity and the spectrum of the Sun in the X-ray band and to the relevant solar emission measure vs. temperature distribution, EM(T ). We also study the relevant changes in the course of four solar rotations, and the solar rotational modulation due to this active region, the only one present at that time. To this end, we have ...