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G. G. Williams (Steward Obs.), P. A. Milne (LANL)
The luminosity of type Ia supernovae (SNe Ia) is initially produced by the gamma-rays which result from the synthesis of radioactive elements during the explosion. At later times (t ~ 200 days) the light curves are powered by the kinetic energy deposited by non-thermal positrons produced in the decay of 56Co to 56Fe. During this late phase, the decline rate of the light curve reflects the degree to which positrons escape the ejecta. This escape fraction is governed by the characteristics of the ejecta, primarily the alignment and strength of the magnetic field and the ionization state of the ejecta. We are conducting a systematic survey to study the physical environments of SNe Ia at these late times. To date we have observed 14 different SNe Ia. We present an overview of our observations with a specific focus on the results from SN2000cx. Early observations of SN2000cx by other groups make it one of the best studied SNe Ia. We have observed SN2000cx during nine late epochs. Our observations at 530 days after the explosion are the latest recorded data from a SN1991T-like peculiar SN Ia.
The author(s) of this abstract have provided an email address for comments about the abstract: gwilliams@as.arizona.edu
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Bulletin of the American Astronomical Society, 34
© 2002. The American Astronomical Soceity.