Abstract of Lecture:

Cosmic explosions were first noted nearly two thousand years ago. However, secure recognition and study began only a hundred years ago. What was once termed as Stella Nova (new stars) are now divided into two major families, novae and supernovae (with real distinct classes in each). Equally the variable stars have a rich phenomenology. Together, supernovae and variable stars have contributed richly to key problems in modern astrophysics: distances to galaxies, cosmography and build up of elements in the Universe. The Palomar Transient Factory (PTF), an innovative 2-telescope system, was designed to explicitly to chart the transient sky with a particular focus on events which lie in the nova-supernova gap. PTF is now finding an extragalactic transient every 20 minutes and a Galactic (strong) variable every 10 minutes. The results so far: ultra-luminous supernovae as the end of the most massive stars in the Universe, progress in understanding the origin of Ia supernovae (which were used by astronomers to discover dark energy), discovery of new classes or sub-classes of supernovae and identification of curious double degenerates of value to future gravitational wave observatories in space.

Brief Biographical Sketch:

S. R. Kulkarni is the McArthur Professor of Astronomy and Professor of Planetary Sciences at the California Institute of Technology. Since 2006 he has been the Director of the Caltech Optical Observatories (2006-present). He is also the Director of NASA Exoplanet Science Institute (NEXSCI). Kulkarni served as the Executive Officer for Astronomy from 1997-2000. In 2007 he was awarded an AD White Professor-at-Large at Cornell University, Ithaca, New York. Kulkarni obtained his undergradute degree from the Indian Institute of Technology, Delhi (1978) and his PhD from UC Berkeley (1983). He served a brief period as a postdoc at UC Berekely and Caltech before joining the faculty rank at Caltech in 1987.

Prof. Kulkarni's primary interests are the study of cosmic explosions, compact objects (neutron stars and gamma-ray bursts), and the search for extra-solar planets through interferometeric and adaptive techniques. He is keenly interested in developing or refining astronomical methodologies. Kulkarni has been involved in a number of discoveries: the first millisecond pulsar, the first cluster pulsars, the first brown dwarf, clarifying the nature of soft gamma-ray repeaters, demonstrating the cosmological origin of gamma-ray bursts and more recently in elucidating super luminous supernovae (with the Palomar Transient Factory).

His awards include the Alan T. Waterman Prize of the NSF, a fellowship from the David and Lucile Packard Foundation, a Presidential Young Investigator award from the NSF, the Helen B. Warner award of the American Astronomical Society and the Karl Janksy Prize of Associated Universities, Inc. Kulkarni was elected as Fellow of the American Academy of Arts and Sciences (1994), Fellow of the Royal Society of London (2001), Fellow of the National Academy of Sciences (2003) and Honorary Fellow, Indian Academy of Sciences (2011).