I present the supernova rates computed from the Mount Stromlo Abell Cluster SN Search (MSACSS) and the High-Z SN Search, two CCD-based searches which use difference imaging techniques. These searches are approximately magnitude-limited with well-defined selection functions, unlike previous visual and photographic surveys which have suffered from selection problems such as deficiencies near the centers of galaxies, poorly-understood detection limits, or preferential treatment of field regions of high galaxy density. The SN samples collected from field galaxies at z<0.2 from the MSACSS ( ~ 60 squ-degree-years to mV ~ 20), rich Abell clusters at 0.02<z<0.08, also from the MSACSS, and field galaxies at z<1.1 from the High-Z Search ( ~ 4 squ-degree-months to mI ~ 24), allow a direct measurement of the SN rate to be determined as a function of redshift, in different underlying stellar populations, and in different environments. These observations provide clues to the nature of type Ia SN projenitors, and a means of tracing star-formation and metal enrichment as a function of lookback time and galaxy environment.
American Astronomical Society Meeting Abstracts
- Pub Date:
- December 1998