[Previous] | [Session 95] | [Next]
P.M. Garnavich (University of Notre Dame)
Indirect evidence connecting classical gamma-ray bursts (GRB) and massive young stars has been building for several years. Late-time "red" bumps in the optical light curves of some afterglows were believed to be supernovae peaking weeks after the GRB. And the unusually energetic type Ic supernova 1998bw was associated with the very subluminous GRB 980425. But the epic burst 030329 has provided conclusive proof that long-soft GRB arise from the core-collapse of massive stars.
The optical afterglow of GRB 030329 was spectacularly bright in comparison to typical bursts owing to its low redshift of z=0.17. On the first day, the well-observed afterglow showed a smooth power-law decay with a steep break that may indicate the jet opening angle. But the following days the light curve became irregular suggesting either density variations in the circumstellar gas or additional energy injection.
A week after the burst, Stanek et al. noted supernova features in the optical spectrum which became more prominent as the afterglow faded. The early spectra of SN 2003dh were very similar to SN 1998bw, a type Ic hypernova. Detailed comparison between the two events is limited by contamination from the irregular afterglow light curve, but indicates SN 2003dh peaked a few days earlier and was slightly less luminous than 1998bw. The range of supernova types that produce GRB is still an open question.
This work was partially funded through NASA grant NAG5-9364.
If you would like more information about this abstract, please follow the link to http://cfa-www.harvard.edu/cfa/oir/Research/GRB/. This link was provided by the author. When you follow it, you will leave the Web site for this meeting; to return, you should use the Back comand on your browser.
The author(s) of this abstract have provided an email address for comments about the abstract: pgarnavi@nd.edu
[Previous] | [Session 95] | [Next]
Bulletin of the American Astronomical Society, 35#5
© 2003. The American Astronomical Soceity.