1. GRB 081029: A Gamma-Ray Burst with a Multi-Component Afterglow
- Author
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Holland, Stephen T, De Pasquale, Massimiliano, Mao, Jirong, Sakamoto, Takanori, Schady, Patricia, Covino, Stefano, Fan, Yi-Zhong, Jin, Zhi-Ping, D'Avanzo, Paolo, Antonelli, Angelo, D'Elia, Valerio, Ohincarini, Guido, Fiore, Fabrizio, Pandey, Shashi Bhushan, and Cobb, Bethany E
- Subjects
Astrophysics - Abstract
We present an analysis of the unusual optical light curve of the gamma-ray burst GRB 081029, a long-soft burst with a redshift of z = 3.8479. We combine X-ray and optical observations from the Swift X-Ray Telescope and the Swift Ultra Violet/Optical Telescope with ground-based optical and infrared data obtained using the REM, ROTSE, and CTIO 1.3-m telescopes to construct a detailed data set extending from 86 s to approx.100,000 s after the BAT trigger. Our data covers a wide energy range, from 10 keV to 0.77 eV (1.24 A to 16000 A). The X-ray afterglow shows a shallow initial decay followed by a rapid decay starting at about 18,000 s. The optical and infrared afterglow, however, shows an uncharacteristic rise at about 3000 s that does not correspond to any feature in the X-ray light curve. Our data are not consistent with synchrotron radiation from a jet interacting with an external medium, a two-component jet, or continuous energy injection from the central engine. We find that the optical light curves can be broadly explained by a collision between two ejecta shells within a two-component jet. A growing number of gamma-ray burst afterglows are consistent with complex jets, which suggests that some (or all) gamma-ray burst jets are complex and will require detailed modelling to fully understand them.injection
- Published
- 2012