10980(  1) - 04/03/06 11:20  - [  1]

                  HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 10980

Version: 1    Check-in Time: 03-Apr-2006 15:20:37

Title
Revisiting the Supernova Ia Rate at z>1
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Type             Cycle     Parallel Pointing Tolerance
AR               15        <none>
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Investigators
                                                                                     Contact?
    PI: Dr. John L. Tonry                 University of Hawaii
   CoI: Mr. Steven A. Rodney              University of Hawaii                          N
   CoI: Dr. Adam Riess                    Space Telescope Science Institute             N
   CoI: Dr. Louis G. Strolger             Western Kentucky University                   N

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Abstract

Type Ia Supernovae (SNIa) are an extremely useful tool for astronomers, contributing
important information for the determination of extragalactic distances, studies of
stellar evolution and galactic chemical evolution, and providing the only direct
evidence for cosmic acceleration. Despite this wide-ranging importance, the origins
of SNIa are fundamentally mysterious. We have good reasons to believe that all SNIa
are the product of a Carbon-Oxygen White Dwarf that reaches the Chandrasekhar mass
limit and ignites carbon burning explosively. However, the precise nature of the
explosion mechanism, the stellar type of the binary companion, and the physical
requirements to reach the critical explosion point are still unclear. We cannot yet
even be sure of whether all SNIa result from a single progenitor track or if there
are multiple ways to set off the explosion. One extremely important constraint on
theoretical models of SNIa progenitors is the evolution of the SNIa rate (SNR) as a
function of redshift. The SNR(z) can distinguish between competing progenitor models
and help to unveil the mystery of these important objects. The most important (and
difficult) component of this measurement is in the highest redshift bins, at z>1,
which requires the unique observing tools of the Hubble Space Telescope (HST). We
propose to revisit the Hubble Space Telescope's Great Observatories Origins Deep
Survey (GOODS) data to dramatically improve the accuracy and precision of the high-z
SNIa rate measurement. We will utilize large numbers of synthetic transients, fully
automated detection techniques, and an improved difference photometry algorithm to
exploit the full potential of this important dataset. Our primary result will be a
strong constraint on SNIa progenitor models from the SNR(z), and along the way we
will also improve the value of this data for future SN studies by determining more
complete and more precise light-curves for the highest redshift SNIa.
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