Abstract:
Unbiased supernova searches led to the recognition of the class of superluminous supernovae (SLSN) about one decade ago. These events can be a factor 100 more luminous than ordinary supernovae. Some SLSNe show narrow hydrogen lines and are likely powered by interaction with a dense circumstellar medium. In one case, the progenitor star lost several solar masses of gas in the 30 years leading to the explosion; the reason for the extreme mass loss is not understood.
Other SLSNe do not show narrow lines, but show broad lines and are stripped of hydrogen. These features are difficult to explain in an interaction scenario. Another possibility is radioactive power, but the required mass of 56Ni can be larger than allowed by the light curve and the expectations of 56Ni synthesis. Power from a magnetar (highly magnetized pulsar) with a millisecond period can roughly explain light curves and spectra.
Brief Bio:
Roger Chevalier has been the W. H. Vanderbilt Professor of Astronomy at the University of Virginia since 1990. After obtaining his Ph.D from Princeton University in 1973, he joined the scientific staff of Kitt Peak National Observatory in Tucson, Arizona. He moved to the University of Virginia in 1979, where he was Astronomy Department chair during 1985-1988 and 1989-1992. His research has centered on theoretical studies of rapidly expanding astronomical sources, including supernovae, supernova remnants, gamma-ray bursts, pulsar wind nebulae, and galactic super-winds. Chevalier was chair of the science panel on Stars and Stellar Evolution for the 2010 astronomy decadal survey. His honors include Virginia's Outstanding Scientist Award (1991), the Dannie Heineman Prize for Astrophysics (1996), and election to the National Academy of Sciences (1996).