Revealing the Jet Structure of Grb 030329 With High Resolution Multicolor Photometry

Gorosabel, Javier ; Castro-Tirado, A. J. ; Ramirez-Ruiz, E. ; Granot, J. ; Caon, N. ; Cairos, L. M. ; Rubio-Herrera, E. ; Guziy, S. ; de Ugarte Postigo, A. ; Jelinek, M.

Stanford Linear Accelerator Center

关键词: Symmetry;    Astrophysics,Astro;    71 Classical And Quantum Mechanics, General Physics;    Afterglow;    Mathematical Models Astrophysics,Astro;   

DOI  :  10.2172/877428
RP-ID  :  SLAC-PUB-11762
RP-ID  :  AC02-76SF00515
RP-ID  :  877428

美国|英语

来源: UNT Digital Library

【 摘 要 】

We present multicolor optical observations of the nearby (z = 0.1685) GRB030329 obtained with the same instrumentation over a time period of 6 hours for a total of an unprecedented 475 quasi-simultaneous B V R observations. The achromatic steepening in the optical, which occurs at t {approx} 0.7 days, provides evidence for a dynamic transition of the source, and can be most readily explained by models in which the GRB ejecta are collimated into a jet. Since the current state-of-the-art modeling of GRB jets is still flawed with uncertainties, we use these data to critically assess some classes of models that have been proposed in the literature. The data, especially the smooth decline rate seen in the optical afterglow, are consistent with a model in which GRB030329 was a homogeneous, sharp-edged jet, viewed near its edge interacting with a uniform external medium, or viewed near its symmetry axis with a stratified wind-like external environment. The lack of short timescale fluctuations in the optical afterglow flux down to the 0.5 per cent level puts stringent constraints on possible small scale angular inhomogeneities within the jet or fluctuations in the external density.