ROSAT X-ray observations of Central Galactic Starbursts

Abstract

We present spatial and spectral results of ROSAT observations of two galaxies: NGC 4569 and NGC 4303. Both objects are members of the Virgo Cluster and have nearby smaller companions with which they have probably gone through an encounter. Both soft X-ray spectra (0.1-2.4 keV) can be fitted with a two-component model consisting of a power-law component from a non-thermal emission of a compact active nucleus and a Raymond-Smith model for a hot thin thermal plasma originating from starbursts. The X-ray luminosities are in the range of 10^40 erg/s. The central source of NGC 4569 is very compact and can not be resolved with the ROSAT HRI detector, while there is extended soft X-ray emission in the galactic disk as well as above it. NGC 4303 is dominated by the active nucleus in the X-ray. But several additional disk sources associated with HII regions can be observed.