Infrared-optical - X-ray simultaneous observations of X-ray flares in GRB 071112C and GRB 080506 - Astrophysics > Cosmology and Nongalactic AstrophysicsReport as inadecuate




Infrared-optical - X-ray simultaneous observations of X-ray flares in GRB 071112C and GRB 080506 - Astrophysics > Cosmology and Nongalactic Astrophysics - Download this document for free, or read online. Document in PDF available to download.

Abstract: We investigate the origin of short X-ray flares which are occasionallyobserved in early stages of afterglows of gamma-ray bursts GRBs. We observedtwo events, GRB 071112C and GRB 080506, before the start of X-ray flares in theoptical and near-infrared NIR bands with the 1.5-m Kanata telescope. Inconjunction with published X-ray and optical data, we analyzed densely sampledlight curves of the early afterglows and spectral energy distributions SEDsin the NIR-X-ray ranges. We found that the SEDs had a break between the opticaland X-ray bands in the normal decay phases of both GRBs regardless of the modelfor the correction of the interstellar extinction in host galaxies of GRBs. Inthe X-ray flares, X-ray flux increased by 3 and 15 times in the case of GRB071112C and 080506, respectively, and the X-ray spectra became harder thanthose in the normal decay phases. No significant variation in the optical-NIRrange was detected together with the X-ray flares. These results suggest thatthe X-ray flares were associated with either late internal shocks or externalshocks from two-component jets.



Author: T. Uehara, M. Uemura, K. S. Kawabata, Y. Fukazawa, R. Yamazaki, A. Arai, M. Sasada, T. Ohsugi, T. Mizuno, H. Takahashi, H. Katagi

Source: https://arxiv.org/



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