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OATS-DAUT SEMINAR
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Speaker: Dan Maoz (School of Physics and Astronomy, Tel-Aviv University)

Title: Supernova Rates: Near and Far, Cluster and Field

Date: Wednesday, April 9th, 2008
Time: 12:00
Venue: Villa Bazzoni

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Abstract:
The measurement of supernova (SN) rates holds great promise, both for tracing the history of cosmic metal enrichment and for understanding the explosions themselves and their progenitors systems. I will describe several ongoing observational programs to measure the rates of type-Ia and core-collapse SNe, as a function of redshift and environment. Based on measurements from the ground and with HST, the SN-Ia rate in galaxy clusters remains low out to redshift z~1, arguing for an early production of the large mass of intracluser metals by a population with a short SN delay time. In the field, I will describe a program with Subaru that aims to measure the SN rate out to z~2, using novel methodologies for SN classification. First results suggest a SN-Ia rate that may be tracking the star-formation history with a small delay, in contrast to the conclusions of the HST-GOODS survey, but in accord with expectations from recent local (z=0) results. Finally, I will discuss a puzzling corollary of all the recent rate measurements: the fraction of the supposed SN-Ia progenitor population that actually explodes as SNe-Ia is suprisingly high -- perhaps higher than possible in any of the currently popular models.
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contact: Elena Pian (OATS)