Swift XRT observations of the afterglow of GRB 050319

被引:48
作者
Cusumano, G
Mangano, V
Angelini, L
Barthelmy, S
Beardmore, AP
Burrows, DN
Campana, S
Cannizzo, JK
Capalbi, M
Chincarini, G
Gehrels, N
Giommi, P
Goad, MR
Hill, JE
Kennea, JA
Kobayashi, S
La Parola, V
Malesani, D
Mészáros, P
Mineo, T
Moretti, A
Nousek, JA
O'Brien, PT
Osborne, JP
Pagani, C
Page, KL
Perri, M
Romano, P
Tagliaferri, G
Zhang, B
机构
[1] INAF, Ist Astrofis Spaziale, I-90146 Palermo, Italy
[2] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA
[3] Johns Hopkins Univ, Baltimore, MD 21218 USA
[4] Univ Leicester, Dept Phys & Astron, Leicester LE1 7RH, Leics, England
[5] Penn State Univ, Dept Astron & Astrophys, Davey Lab 525, University Pk, PA 16802 USA
[6] INAF, Osservat Astron Brera, I-23807 Merate, Italy
[7] ASI, Sci Data Ctr, I-00044 Frascati, Italy
[8] Univ Milan, Dipartimento Fis, I-20126 Milan, Italy
[9] SISSA, ISAS, Int Sch Adv Studies, I-34014 Trieste, Italy
[10] Univ Nevada, Dept Phys, Las Vegas, NV 89154 USA
关键词
gamma rays : bursts; X-rays : individual (GRB 050319);
D O I
10.1086/499292
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
Swift discovered the high-redshift GRB 050319 with the Burst Alert Telescope (BAT) and began observing with its narrow-field instruments only 225 s after the burst onset. The afterglow X-ray emission was monitored by the XRT up to 28 days after the burst. The light curve shows a decay with three different phases, each characterized by a distinct slope: an initial steep decay with a power-law index of similar to 5.5, a second phase characterized by a flat decay slope of similar to 0.54, and a third phase with a decay slope of similar to 1.14. During the first phase the spectral energy distribution is softer than in the following two phases, and the photon index is consistent with the GRB prompt spectrum. The extrapolation of the BAT light curve to the XRT band suggests that the initial fast-decaying phase of the XRT afterglow might be the low-energy tail of the prompt emission. The second break in the afterglow light curve occurs about 27,000 s after the burst. The spectral energy distribution before and after the second break does not change, and it can be tentatively interpreted as a jet break or the end of a delayed or continuous energy injection phase.
引用
收藏
页码:316 / 322
页数:7
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