A New View of the LHB and 1/4 keV X-ray Halo
S. L. Snowden;
LNP, 1998, 506, 103
ABSTRACT:The X-ray sky at 1/4 keV is completely dominated by diffuse emission.
It has become clear that it originates as at least three separate
components: local emission within the nearest ~100 pc from the Sun, halo emission
from beyond most of the neutral material of the Galactic disk, and the
superposition of unresolved extragalactic sources.
The only way to determine the
temperatures and relative emission measures of the hot plasma responsible for the
Galactic components is to use the X-ray intensity variations due to column
density variations in the intervening H I to separate the components.
``Shadowing'' studies have been pursued for individual objects using ROSAT data from
both pointed observations and the all-sky survey with considerable
success.
This paper presents the results of an all-sky analysis of the 1/4 keV
background from the ROSAT survey.
A Local Hot Bubble is found consistent with,
although somewhat smaller than, previous models.
It has a temperature of
10^{6.1} K and an emission measure which varies by a factor of ~3.3 over large
angles.
The halo emission has a temperature near 10^{6.0} K with an emission
measure which varies from near zero to more than five times that of the local
emission.
CODE: snowden98