RX J100058.9+555141 , the SIMBAD biblio

We report the results of the spatial and spectral analysis of the ROSAT HRI and PSPC observations of the edge-on spiral galaxy NGC 3079. We detected several sources in the field of NGC 3079 with both PSPC and HRI, and complex emission from the inner 5' around NGC 3079. We have identified possible counterparts for several of the sources outside NGC 3079 by comparison with optical plates and catalogues. The X-ray emission from NGC 3079 has a L_X=3x10⁴⁰erg/s and can be resolved into the following three components: (o) Extended emission in the innermost region, with L_X=1x10⁴⁰erg/s, coincident with the super-bubble seen in optical images. The active nucleus may contribute to the emission as a point source. (o) Emission from the disk of the galaxy, with L_X=7x10³⁹erg/s, that can be partly resolved by the HRI in 3 point-like sources with luminosities of ∼6x10³⁸erg/s each. (o) Very soft X-shaped emission from the halo, with L_X=6x10³⁹erg/s, extending to a diameter of 27kpc. The X-ray luminosity of NGC 3079 is higher by a factor of 10 compared to other galaxies of similar optical luminosity and we argue that this may be caused by the presence of an AGN rather than by starburst activity. The influence of the AGN on the companion galaxies in the NGC 3079 group are discussed.