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 resul ts from the ROSAT soft X-ray all-sky survey. These maps cover similar to 98% of the sky in the 1/4 keV, 3/4 keV, and 1.5 keV bands, with sim ilar to 2 degrees angular resolution and high sensitivity for low surf ace brightness extended features. The effects of non-X-ray contaminati on and X-rays of solar system origin have been eliminated to the great est possible extent, but discrete X-ray sources have not been removed. The much improved angular resolution, statistical precision, and comp leteness of coverage of these maps reveal 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.