First maps of the soft X-ray diffuse background from the ROSAT XRT/PSPC all-sky survey

This paper presents an initial version of the diffuse background results from the ROSAT soft X-ray all-sky survey. These maps cover #approx# 98% of the sky in the 1/4 keV, 3/4 keV, and 1.5 keV bands, with #approx# 2 angular resolution and high sensitivity for low surface brightness extended features. The effects of non-X-ray contamination and X-rays of solar system origin have been eliminated to the greatest possible extent, but discrete X-ray sources have not been removed. The much improved angular resolution, statistical precision, and completeness of coverage of these maps reveals considerable structure over the entire 0.1 - 2.0 keV energy range that was not observed previously. The data agree well with previous all-sky surveys in terms of absolute normalization and zero point. (orig.)Available from TIB Hannover: RN 9303(335) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

ROSAT survey diffuse X-ray background maps. Paper 2

This paper presents new maps of the soft X-ray background from the ROSAT all-sky survey. These maps represent a significant improvement over the previous version in that(1) the position resolution of the PSPC has been used to improve the angular resolution from #propor to#2 to 12', (2) there are six energy bands that divide each of the previous three into two parts, and(3) the contributions of point sources have been removed to a uniform source flux level over most of the sky. These new maps will be available in electronic format in 1997. In this paper we also consider the bright emission in the general direction of the Galactic center in the 0.5-2.9 keV band, and the apparent absorption trough that runs through it along the Galactic plane. We find that while the northern hemisphere data are confused by emission from Loop I, the emission seen south of the plane is consistent with a bulge of hot gas surrounding the Galactic center (in our simple model, a cylinder with an exponential fall-off density with height above the plane). The cylinder has a radial extent of #propor to#5.6 kpc. The X-ray emitting gas has a scale height of 1.9 kpc, an in-plane electron density of #propor to#0.0035 cm"-"3, a temperature of #propor to#10"6"."6 K, a thermal pressure of #propor to#28,000 cm"-"3 K, and a total luminosity of #propor to#2 x 10"3"9 ergs s"-"1 using a collisional ionization equilibrium (CIE) plasma emission model. (orig.)SIGLEAvailable from FIZ Karlsruhe / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman