Rykoff 2009 ROTSE-III and Swift对早期余辉的观测

主要内容:
主要是光学的观测数据. 包括的暴有:
GRB 050319, GRB 050401, GRB 050525a,
GRB 050801, GRB 050922c, GRB 051109a, GRB 060111b, GRB 060605,
GRB 060729, GRB 060904b, GRB 061007, GRB 070611

还包括确定了一些initial LF.

精彩摘抄:


文章信息:

arXiv:0904.0261 [ps, pdf, other]

Title: Looking Into the Fireball: ROTSE-III and Swift Observations of Early GRB Afterglows

Authors: E. S. Rykoff (UCSB), F. Aharonian (MPIK), C. W. Akerlof (UMich), M. C. B. Ashley (UNSW), S. D. Barthelmy (GSFC), H. A. Flewelling (UMich), N. Gehrels (GSFC), E. Gogus (Sabanci), T. Guver (Arizona), U. Kiziloglu (METU), H. A. Krimm (GSFC, USRA), T. A. McKay (UMich), M. Ozel (Cag), A. Phillips (UNSW), R. M. Quimby (Caltech), G. Rowell (Adelaide), W. Rujopakarn (Steward), B. E. Schaefer (LSU), D. A. Smith (Guilford), W. T. Vestrand (LANL), J. C. Wheeler (UTexas), J. Wren (LANL), F. Yuan (UMich), S. A. Yost (CSB/SJU)

Comments: 31 pages, 5 figures, submitted to ApJ

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Cosmology and Extragalactic Astrophysics (astro-ph.CO)

We report on a complete set of early optical afterglows of gamma-ray bursts (GRBs) obtained with the ROTSE-III telescope network from March 2005 through June 2007. This set is comprised of 12 afterglows with early optical and Swift/XRT observations, with a median ROTSE-III response time of 45 s after the start of gamma-ray emission (8 s after the GCN notice time). These afterglows span four orders of magnitude in optical luminosity, and the contemporaneous X-ray detections allow multi-wavelength spectral analysis. Excluding X-ray flares, the broadband synchrotron spectra show that the optical and X-ray emission originate in a common region, consistent with predictions of the external forward shock in the fireball model. However, the fireball model is inadequate to predict the temporal decay indices of the early afterglows, even after accounting for possible long-duration continuous energy injection. We find that the optical afterglow is a clean tracer of the forward shock, and we use the peak time of the forward shock to estimate the initial bulk Lorentz factor of the GRB outflow, and find 100 .lt. Gamma_0 .lt. 1000, consistent with expectations.