PROGRESS ON ESTABLISHING THE SPATIAL-DISTRIBUTION OF MATERIAL RESPONSIBLE FOR THE 1 4 KEV SOFT-X-RAY DIFFUSE BACKGROUND LOCAL AND HALO COMPONENTS/

In this paper we present a new look at the distribution of emission re sponsible for the soft X-ray diffuse background (SXRB) using ROSAT all -sky survey data. This is prompted by the demonstration of the existen ce of extensive 1/4 keV emission in the Galactic halo that was not con sidered in the most successful previous model, in which the bulk of th e observed 1/4 keV X-rays originated in a Local Hot Bubble (LHB) that surrounds the Sun. The basic distribution can be represented by two an gularly varying Galactic components (the LHB and an X-ray halo) and an isotropic extragalactic component. In addition, there are the distinc t enhancements of supernova remnants, superbubbles, and clusters of ga laxies. Using the negative correlation between the SXRB and DIRBE-corr ected IRAS 100 mu m intensity, we find a LHB that is similar to previo us models, although it is possibly more limited in extent. The emissio n of the LHB varies by a factor of similar to 3.3 with direction and p roduces ROSAT 1/4 keV intensities between similar to 250 and similar t o 820 x 10(-6) counts s(-1) arcmin(-2) (typically brighter at higher G alactic latitudes), with inferred emission measures of similar to 0.00 18 to 0.0058 cm(-6) pc (assuming thermal ionization equilibrium). The distribution of the emission temperature of the LHB is peaked at 10(6. 07) K with a range of +/-12% at FWHM. While this variation is small an d is perhaps due to systematic uncertainties in the analysis, there is a suggestion of a cooler region in the anticenter direction consisten t with previous studies. We derive halo plus extragalactic intensities that vary from similar to 400 to greater than or similar to 3000 x 10 (-6) counts s(-1) arcmin(-2) outside the absorbing gas of the Galactic disk. As the low end of the range is comparable to what is expected f or the extragalactic background, this implies that the halo emission v aries considerably over the sky, with inferred emission measures rangi ng from near zero to >0.02 cm(-6) pc. The distribution of emission tem peratures in the halo, again derived from thermal equilibrium emission models, peaks near 10(6.02) K and varies over +/-20% at FWHM.