X-RAY OBSERVATIONS OF THE INTERACTING-SYSTEM ARP-284

We discuss the X-ray properties of the interacting system Arp 284, con sisting of the active nuclear starburst galaxy NGC 7714 and its post-s tarburst companion NGC 7715. A morphological signature of the interact ion, thought to have started < 100 Myr ago, is an asymmetric stellar r ing dominating the intensity profile of NGC 7714 in the inner disk (si milar to 2 exponential scale lengths). In agreement to previous Einste in-data our ROSAT PSPC exposure shows the X-ray emission of Arp 284 to be confined to NGC 7714. The bulk of the intrinsic X-ray luminosity i n the ROSAT 0.1-2.4 keV band can be accounted for by thermal emission from hot (similar to 5 x 10(6) K) gas and amounts to similar to 2 - 4 x 10(41) erg s(-1). Follow-up observations with the ROSAT HRI revealed two distinct extended emitting regions contributing to the X-ray lumi nosity in NGC 7714. The more luminous of them (L-X less than or simila r to 2 x 1041.,s,-1) coincides with the central starburst nucleus and can be explained this way. The fainter one (L-X similar to 8 x 10(40) erg s(-1)) is located similar to 20 '' off-center and does not have an y conspicuous optical counterpart. It is, likely, located at the borde rline between the stellar ring and a massive (> 10(9) M.) HI-bridge fu rther to the east possibly intersecting NGC 7714. The HI and X-ray mor phology and the extensive starburst nature of the nuclear energy sourc e suggest different scenarios for the formation of the eastern emissio n spot. The possibilities of (i) collisional heating of the outlying g as by a starburst-driven nuclear wind and (ii) infall of HI-clouds fro m the bridge onto the disk of NGC 7714 are discussed.