van der Horst 2007 GRB 030329深度非相对论的射电辐射观测

主要内容:
给出了一直到1128天的射电观测。用一般模型限制了一些参数。

精彩摘抄:


文章信息:
arXiv:0706.1321 [ps, pdf, other] : Title: Detailed study of the GRB 030329 radio afterglow deep into the non-relativistic phase
Authors: A.J. van der Horst, A. Kamble, L. Resmi, R.A.M.J. Wijers, D. Bhattacharya, B. Scheers, E. Rol, R. Strom, C. Kouveliotou, T. Oosterloo, C.H. Ishwara-Chandra
Comments: 9 pages, 2 figures, submitted to Astronomy & Astrophysics

We explore the physics behind one of the brightest radio afterglows ever, GRB 030329, at late times when the jet is non-relativistic. We determine the physical parameters of the blast wave and its surroundings, in particular the index of the electron energy distribution, the energy of the blast wave and the density (structure) of the circumburst medium; and compare our results with results from image size measurements. We observed the GRB 030329 radio afterglow with the Westerbork Synthesis Radio Telescope and the Giant Metrewave Radio Telescope at frequencies from 325 MHz to 8.4 GHz, spanning a time range of 268-1128 days after the burst. We modeled all the available radio data and derived the physical parameters. The index of the electron energy distribution is p=2.1, the circumburst medium is homogeneous, and the transition to the non-relativistic phase happens at t_NR ~ 80 days. The energy of the blast wave and density of the surrounding medium are comparable to previous findings. Our findings indicate that the blast wave is roughly spherical at t_NR, and they are in agreement with the implications from the VLBI studies of the image size evolution. It is not clear from the presented dataset whether we have seen emission from the counter jet or not. We predict that the Low Frequency Array will be able to observe the afterglow of GRB 030329 and many other radio afterglows, constraining the physics of the blast wave during its non-relativistic phase even further.