GRB 021004 modelled by multiple energy injections
/ Authors
A. U. Postigo, A. Castro-Tirado, J. Gorosabel, G. J'ohannesson, G. Bjornsson, E. Gudmundsson, M. Bremer, S. Pak, N. Tanvir, J. M. C. Cer'on
and 36 more authors
S. Guzyi, M. Jel'inek, S. Klose, D. P'erez-Ram'irez, J. Aceituno, A. C. Bagat'in, S. Covino, N. Cardiel, T. Fathkullin, A. Henden, S. Huferath, Y. Kurata, D. Malesani, F. Mannucci, P. Ruiz-Lapuente, V. Sokolov, U. Thiele, L. Wisotzki, L. A. Antonelli, C. Bartolini, A. Boattini, A. Guarnieri, A. Piccioni, G. Pizzichini, M. Principe, A. Paola, D. Fugazza, G. Ghisellini, L. Hunt, T. Konstantinova, N. Masetti, E. Palazzi, E. Pian, M. Stefanon, V. Testa, P. Tristram
/ Abstract
GRB021004 is one of the best sampled gamma-ray bursis (GRB) to date. although the nature of its light curve is still being debated. Here we present 107 new optical, near-infrared (NIR) and millimetre observations, ranging from 2 h to more than a year after the burst. Fitting the inultiband data to a model based on multiple energy injections suggests that at least 7 refreshed shocks took place during the evolution of the afterglow, implying a total energy release (collimated within an angle of 1:8) of ∼8 x 10 51 erg. Analysis of the late photometry reveals that the GRB021004 host is a low extinction (A V ∼ 0.1) starburst galaxy with M B ≃ -22.0.
Journal: Astronomy and Astrophysics