Department of Physics & Astronomy

Fall 2008 Colloquia


Maryam Modjaz

Maryam Modjaz

Miller Fellow
University of California, Berkeley
Understanding the Deaths of Massive Stars
October 20, 2008, 4PM, Thornton 411

Massive Stars die violently. During their explosive deaths, they are as luminous as billions of stars combined; they synthesize and eject heavy elements and an enormous amount of energy; and they leave behind fascinating objects such as black holes and neutron stars. However, it is not well-understood what kind of death they undergo -- whether they die as a supernova of type Ib/c, as a gamma-ray burst, or as a combination of both. Type Ib/c supernovae (SN) are stellar explosions that synthesize radioactive nickel which decays to iron and that originate from stars that have been stripped of progressively larger amounts of their hydrogen and helium envelopes. Gamma-ray bursts (GRBs) are explosions that emit flashes of high-energy radiation in narrow jets, temporarily outshining the entire universe in gamma-rays.

In this talk I will discuss a number of observational venues that attempt to probe the explosion conditions and environments of SN with and without GRBs. Moreover, I will present extensensive data on SN Ib 2008D. SN 2008D was discovered serendipitously in January 2008 with the NASA Swift satellite via its X-ray emission and has generated great interest by astronomers (10 papers and counting).
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