ROSAT Survey Diffuse X-Ray Background Maps. II.
S. L. Snowden, R. Egger, M. J. Freyberg, D. McCammon, P. P. Plucinsky, W. T. Sanders, J. H. M. M. Schmitt, J. Truemper, W. Voges;
ApJ, 1997, 485, 125
ABSTRACT: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 ~2 deg 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 later
in 1997.
In this paper we also consider the bright emission in the general
direction of the Galactic center in the 0.5--2.0 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 of density with height above the plane).
The cylinder has a radial
extent of ~5.6 kpc.
The X-ray emitting gas has a scale height of 1.9 kpc, an
in-plane electron density of ~0.0035 cm-3, a temperature of ~106.6 K, a thermal
pressure of ~28,000 cm-3 K, and a total luminosity of ~2 x 1039 ergs s-1 using a
collisional ionization equilibrium (CIE) plasma emission model.
KEYWORDS: cosmology: diffuse radiation, galaxy: center, surveys, x-rays: galaxies, x-rays: ism
PERSOKEY:xrays, milky way, h+, ,
CODE: snowden97