NOAO >   Observing Info >   Approved Programs >   2012A-0556

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Proposal Information for 2012A-0556


PI: D. Andrew Howell, Las Cumbres Observatory / University of California Santa Barbara, ahowell@lcogt.net
Address: 6740 Cortona Dr., Santa Barbara, CA 93111, USA

CoI: Mark Sullivan, Oxford University
CoI: Jerod Parrent, Las Cumbres Observatory / Dartmouth College
CoI: Peter Nugent, Lawrence Berkeley National Lab
CoI: Isobel Hook, Oxford University
CoI: Ben Dilday, Las Cumbres Observatory / University of California Santa Barbara
CoI: Kate Maguire, Oxford University
CoI: Melissa Graham, Las Cumbres Observatory / University of California Santa Barbara

Title: Early-time observations of Type Ia supernovae to reveal progenitors

Abstract: SNe Ia remain nature's best standardized candles, and yet their progenitors have long been a mystery. However, in a series of three studies this year, our group has placed the first serious constraints on the progenitors of two SNe Ia, finding (1) the first hard evidence that the primary is a CO white dwarf star; (2) in one case the white dwarf is accreting from a mass-losing evolved secondary and has become a recurrent nova like RS Oph; (3) in another case a system like RS Oph is ruled out and the companion is probably a main sequence star. Taken together with our earlier work implicating white dwarfs mergers in the super-Chandra systems, we are led to the remarkable conclusion that there are a multiplicity of progenitors for SNe Ia. This may explain our finding that supernovae in different environments correct to different absolute magnitudes, and could have serious implications for cosmology. Our results depend on early-time observations for which the queue-scheduled Gemini is uniquely suited. We will use these data to rapidly trigger high-resolution searches for circumstellar material at Keck and VLT, and the Gemini data will directly probe the unburned progenitor material in the supernovae themselves.


National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360



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