The ROTSE Project at SMU

Photo Supernovae and gamma-ray bursts are catastrophic stellar explosions which mark the final end of a star’s long struggle to balance the crushing power of gravity against the outward radiant pressure generated from their inner thermonuclear furnaces. The physics involved in these events still has many unanswered questions, including the true nature of the progenitors in what are termed Type Ia supernovae. These are believed to be a large, luminous red giant star orbited by a dead, superdense white dwarf companion. Here the white dwarf steals matter from the giant and eventually crosses a critical threshold, called the Chandrasekhar limit, where the white dwarf can no longer support its weight and collapses. These supernovae now also serve as a critical element in the cosmologist’s toolkit, having led to the discovery and study of the accelerating expansion of the universe and dark energy. Because the mass limit of white dwarf is fixed, these supernovae theoretically provide a ‘standard candle’ allowing their distances to be determined. The ROTSE effort has been focused on studying these events to test these theories and to help provide better constraints when using these events for cosmology. The SMU group pursues studies of Type Ia supernovae, as well as core-collapse supernovae that may provide another complementary test of cosmology.