This paper reports the results of the analysis of the second ROSAT PSPC survey of M31 performed in summer 1992. We compare our results with those of the first survey, already published in Supper et al. (1997). Within the ∼ 10.7 deg field of view, 396 individual X-ray sources are detected in the second survey data, of which 164 are new detections. When combined with the first survey, this result...

The ROSATmission gave us the unique possibility to study the galactic interstellar medium by “shadowing” observations on arcmin angular resolution level. The high sensitivity of the ROSAT PSPC in combination with the large field of view allows the detailed study of individual clouds, while the ROSAT all-sky survey is the main source for studies of the large-scale intensity distribution of the d...

We illustrate a procedure to estimate the length of stellar coronal loops from the decay of X-ray flares observed with ROSAT/PSPC. As we did in the first paper of this series for solar flares, we use extensive hydrodynamic modeling, and the synthesis of observable quantities from the model results, to obtain an expression for the loop length in terms of parameters readily derivable from spectra...

We use new ASCA observations and archival ROSAT Position Sensitive Proportional Counter (PSPC) data to determine the X-ray spectral properties of the intracluster gas in Abell 644. From the overall spectrum, we determine the average gas temperature to be 8.64 −0.56 keV, and an abundance of 0.32 ± 0.04 Z⊙. The global ASCA and ROSAT spectra imply a cooling rate of 214 −91 M⊙ yr −1. The PSPC X-ray...

BACKGROUND Pneumococcal meningitis (PM) is a life-threatening disease with a high case-fatality rate and elevated risk for serious neurological sequelae. In this study, we investigated the contribution of three major virulence factors of Streptococcus pneumoniae, the capsule, pneumococcal surface protein A (PspA) and C (PspC), to the pathogenesis of experimental PM. METHODS Mice were challeng...

We performed timing and spectral analysis for PSR B1929+10, one of the oldest (about 10 years) of the ordinary pulsars detected in X-rays, using archival ROSAT, ASCA and RXTE data. Pulsed emission was detected at a more than five sigma level for combined ROSAT PSPC and unpublished HRI data. Our pulse profile is in agreement with that obtained by Yancopoulos et al. (1994; ROSAT PSPC) but now wit...

We report the discovery of a powerful and variable off-nuclear X-ray source in the nearby spiral galaxy NGC 4945. Two ROSAT PSPC observations show the source to brighten in 0.5–2.0 keV flux by a factor of ≈ 9 on a time-scale of 11 months or less. It is seen by ASCA about one month after the second PSPC pointing, and is seen to have dimmed by a factor of > ∼ 7 in a ROSAT HRI pointing about one y...

We have analysed archival ROSAT PSPC and Einstein HRI data for the x-ray point source in the bar of NGC 6822. The source decreased in x-ray flux by at least half an order of magnitude in the 13 years between the HRI and PSPC observations. It has a PSPC flux of fX ≈ 8× 10 erg cm s, giving LX ≈ 2.4 × 10 erg s for a distance of 500 kpc. The source appears to be related to the optical emission-line...

We report the serendipitous discovery of a flare star observed with the ROSAT X-ray observatory. From optical spectra, which show strong and variable emission lines of the hydrogen Balmer series and neutral helium, we classify this object as a M3.0Ve star, and estimate a distance of 52 pc from published photometry. Due to the star's close proximity (13.6 ′) to the calibration source and RS CVn ...