Colloquium on 13 February 2017
Double degenerate binaries in spectroscopic surveys


Title: Double degenerate binaries in spectroscopic surveys
Speaker: Dr Elmé Breedt (University of Warwick)
Date: Monday, 13 February 2017
Time: 11:00 - 12:00
Venue: SAAO Auditorium


The use of type Ia supernovae (SNIa) in cosmology over the past decade has led to a huge amount of research on SNIa, but the exact nature of their progenitors is still unclear. Here we consider the double degenerate population in the Galaxy, and whether there are enough of them to account for the observed SNIa rate. To answer this question we need multiple radial velocity measurements of ideally thousands of white dwarfs, as only a small fraction of the double degenerate population is massive enough, with orbital periods short enough, to be considered viable Type Ia progenitors. We show how the radial velocity information available from public surveys such as the Sloan Digital Sky Survey can be used to pre-select targets for variability, leading to a ten-fold reduction in observing time required compared to an unranked or random survey.

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