Chandra Observations of Arp 220: The Nuclear Source

Abstract

We have observed the archetypal Ultraluminous Infrared Galaxy (ULIRG), Arp220, with Chandra for an integration time of 60ks using the ACIS instrument. This provides excellent imaging quality as well as low resolution spectral information. The resulting image contains plentiful structure relating to the starburst and the associated X-ray emitting superwind. In the nuclear regions we find evidence for a luminous source of of hard X-rays. The nature of this source is of great importance to our understanding of ULIRGs and their relation to other classes of object, such as quasars and the sources responsible for the cosmic infrared background. We discuss the results of our observations concerning this source, and what they might mean for the role of ULIRGs