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Bridging the gap : elusive explosions in the local universe


Kasliwal, Mansi M. (2011) Bridging the gap : elusive explosions in the local universe. Dissertation (Ph.D.), California Institute of Technology.


For centuries, we have known that our dynamic universe is adorned by cosmic fireworks: energetic and ephemeral beacons of light from a single star that are a million (nova) to a billion (supernova) times brighter than our sun. However, it had been an age-old conundrum that the brightest nova is approximately 1000 times fainter than than the faintest supernova; why should nature leave such a wide "gap"? In search of an answer, I undertook three systematic surveys for my thesis. Since I was looking for transients fainter, faster and rarer than supernovae, I focused my search on galaxies in the local universe. We now have convincing evidence of multiple, distinct populations of rare transients bridging this "gap". Perhaps, we are witnessing new stellar physics --- shell detonations in ultra-compact white dwarf binaries, electron-capture supernovae, white dwarfs collapsing into neutron stars and birth of black-holes. A small number of intensively followed-up discoveries of elusive transients sets the stage for population studies with the upcoming "Large Synoptic Survey Telescope". This effort works towards building a complete inventory of transients in the local universe (d < 200 Mpc). It better prepares us for the search for potential electromagnetic counterparts to events in the emerging fields of gravitational wave, neutrino and ultra high energy cosmic ray astronomy as these experiments are also limited to the local universe.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:astronomy; transient; nova; supernova; palomar; keck; survey; local universe; nearby galaxies; photometry; spectroscopy; optical; radio; infrared; ultraviolet; gamma-ray; x-ray; evla; swift; gap; macronova; white dwarf; neutron star; black hole;
Degree Grantor:California Institute of Technology
Division:Physics, Mathematics and Astronomy
Major Option:Astrophysics
Awards:Everhart Lecture, 2011
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Kulkarni, Shrinivas R.
Thesis Committee:
  • Ellis, Richard S. (chair)
  • Phinney, E. Sterl
  • Harrison, Fiona A.
  • Readhead, Anthony C. S.
  • Frail, Dale A.
  • Kulkarni, Shrinivas R.
Defense Date:26 April 2011
Author Email:mansi (AT)
Funding AgencyGrant Number
Gordon and Betty Moore FoundationHale Fellowship
Palomar Transient Factory CollaborationCOO, CIT, LCOGT, Columbia, LBNL, WIS, Oxford
National Science FoundationAST-1009987
Projects:Palomar Transient Factory (PTF), Palomar 60-inch Fast Transients In Nearest Galaxies (P60-FasTING), Canada France Hawaii Telescope Coma and Virgo Exploration for Transients (CFHT-COVET)
Record Number:CaltechTHESIS:05162011-094345225
Persistent URL:
Kasliwal, Mansi M.0000-0002-5619-4938
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:6395
Deposited By: Mansi Kasliwal
Deposited On:31 May 2011 23:09
Last Modified:18 Mar 2015 23:46

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PDF (Kasliwal PhD Thesis) - Final Version
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