SN 2007bg: The Complex Circumstellar Environment Around One of the Most Radio-Luminous Broad-Lined Type Ic Supernovae
Abstract
A direct link between SNe and their progenitors is key in determining how SNe work. Among SNe, type Ic are of special interest because of their association with gamma-ray bursts, e.g., SN 1998bw and GRB 980425. Fortunately radio and X-ray emission from SNe are by-products of the interaction of the SN shock with the pre-SNe circumstellar density. Also, we can detect the signature of a gamma-ray burst from the radio emission, as it was in the case of SN 2009bb. We have reduced and analyzed all publicly available radio and X-ray data of the type Ic broad-lined SN 2007bg, which shows three distinct phases of temporal and spectral evolution, implying that the SNe shock likely encountered at least 2 different circumstellar medium regimes. SN 2007bg is one of only a few type Ic's broad-lined SNe to be detected at radio wavelengths and in which changes in the light curve are well-sampled. This light curve variations are the strongest observed to date in a Ic SNe, with a second peak luminosity 2.6 times the luminosity during the first peak. The data provide robust evidence for strong global changes in at least some Ic broad-lined progenitors, and is consistent with a compact Wolf-Rayet progenitor based on the mass-loss rates.
- Publication:
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American Astronomical Society Meeting Abstracts #221
- Pub Date:
- January 2013
- Bibcode:
- 2013AAS...22123301S