ROSAT PSPC AND HRI OBSERVATIONS OF THE COMPOSITE STARBURST SEYFERT-2 GALAXY NGC-1672

The nearby barred spiral galaxy NGC 1672 is thought to have a weak Sey fert nucleus in addition to its strong starburst activity. Observation s with the Position Sensitive Proportional Counter (PSPC) and High Res olution Imager (HRI) instruments on board the ROSAT X-ray satellite sh ow that three X-ray sources with luminosities (1-2) x 10(40) erg s(-1) are clearly identified with NGC 1672. The strongest X-ray source lies at the nucleus, and the other two lie near the ends of the prominent bar, locations that are also bright in Ha and near-infrared images. Th e nuclear source is resolved by the HRI on about the scale of the rece ntly identified nuclear ring, and one of the sources at the ends of th e bar is also probably resolved. The X-ray spectrum of the nuclear sou rce is quite soft, having a Raymond-Smith plasma temperature of approx imate to 0.7 keV and little evidence for intrinsic absorption. The ROS AT band X-ray flux of the nuclear source appears to be dominated not b y X-ray binary emission but rather by diffuse gas emission. While the properties of the nuclear source are generally supportive of a superbu bble interpretation, its large density and emission measure stretch th e limits that can be comfortably accommodated by such models. We do no t detect direct emission from the putative Seyfert nucleus, although a n alternative model for the nuclear source is thermal emission from ga s that is photoionized by a hidden Seyfert nucleus. The spectra of the other two X-ray sources are harder than that of the nuclear source, a nd superbubble models for them have the same strengths and weaknesses.