%0 Journal Article
%T ROSAT observations of the dwarf starforming galaxy Holmerg II (UGC 4305)
%A A. L. Zezas
%A I. Georgantopoulos
%A M. J. Ward
%J Physics
%D 1999
%I arXiv
%R 10.1046/j.1365-8711.1999.02626.x
%X We present ROSAT PSPC and HRI observations of the dwarf irregular galaxy Holmberg II (UGC4305). This is one of the most luminous dwarf galaxies (Lx~ 10^{40} erg s^{-1} cm^{-2}) detected in the ROSAT All-Sky Survey. The X-ray emission comes from a single unresolved point source, coincident with a large HII region which emits intense radio emission. The source is variable on both year and day timescales, clearly favouring accretion into a compact object rather than a supernova remnant or a superbubble interpretation for the origin of the X-ray emission. However, its X-ray spectrum is well-fit by a a Raymond-Smith spectrum with kT~0.8 keV, lower than the temperature of X-ray binaries in nearby spiral galaxies.
%U http://arxiv.org/abs/astro-ph/9903355v1