Astron. Astrophys. 321, 81-83 (1997)

1. Introduction

Ultraluminous infrared galaxies (hereafter ULIGs) are dissipative collapses in progress (see Sanders & Mirabel 1996 for a recent review). Their huge infrared luminosities () are the result of the thermal emission from dust surrounding either starbursts or active galactic nuclei (AGN). Large amounts of gas have fallen to small radii resulting in extremely high densities; this gas is observed through its molecular transitions (Solomon et al. 1992). These high densities are presumably responsible for the starburst or AGN (Sanders et al. 1988) which in turn is reponsible for the huge . High-resolution imaging of ULIGs indicates that the usual trigger of this collapse is a recent merger (Clements et al. 1996).

Therefore, we might expect to see a high rate of Type II Supernovae (SN II) in ULIGs. This is because SN II come from the core-collapse explosion of very massive young stars, in contrast to the normally more luminous Type Ia supernovae (hereafter SN Ia) which come from exploding carbon-oxygen white dwarfs. Until now, none have been discovered in the extremely luminous ULIGs with ; there are such galaxies known (Sanders & Mirabel 1996). However two SN (Treffers et al. 1993, van Buren et al. 1994) have been recently observed in the slightly less extreme starburst galaxy NGC 3690 (, Carico et al. 1990). This paper reports the discovery of a candidate supernova (hereafter SN) in the ULIG IRAS 12112+0305 (, Sanders et al. 1988). Our observations are limited but do indeed suggest that this is a SN II.

Throughout this paper we assume km s^-1 Mpc^-1.

© European Southern Observatory (ESO) 1997

Online publication: June 30, 1998
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