ar X iv : a st ro - p h / 03 07 52 0 v 1 3 0 Ju l 2 00 3 Supernovae in Galaxy Clusters

1 Abstract We present the results of several surveys for supernovae (SNe) in galaxy clusters. SNe discovered in deep, archival HST images were used to measure the cluster SN Ia rate to z = 1. A search for SNe in nearby (0.06 ≤ z ≤ 0.2) Abell galaxy clusters yielded 15 SNe, 12 of which were spectroscopically confirmed. Of these, 7 are cluster SNe Ia, which we will use to measure the SN Ia rate in nearby clusters. This search has also discovered the first convincing examples of intergalactic SNe. We conclude with a brief description of ongoing and future cluster SN surveys. 2 Introduction This contribution describes our observational studies of SNe in galaxy clusters. The motivation to search for SNe in the fields of rich galaxy clusters is discussed in a contribution by Maoz et al. (this volume), and more fully by Gal-Yam, Maoz & Sharon [1] and Maoz & Gal-Yam [4]. Observationally, SN searches in galaxy clusters were pioneered in the late 1980's by Norgaard-Nielsen et al. [5], resulting in the first detection of a z = 0.31 SN in the galaxy cluster AC118. More recently, low-redshift clusters have been monitored for SNe by the Mount Stromlo Abell Cluster SN Search [6]). We present below the results from several surveys for SNe in galaxy clusters we have carried out using both ground-based telescopes and the Hubble Space Telescope (HST).