GRB 071112C: A Case Study of Different Mechanisms in X-ray and Optical Temporal Evolution

Huang KY

Urata Y

Tung YH

Lin HM

Xin LP

Yoshida M

Zheng W

Akerlof C

Wang SY

Ip WH

Lehner MJ

Bianco FB

Kawai N

Kuroda D

Marshall SL

Schwamb ME

Qiu Y

Wang JH

Wen CY

Wei J

Yanagisawa K

Zhang ZW

Astrophysical Journal

We present a study on GRB 071112C X-ray and optical light curves. In these two wavelength ranges, we have found different temporal properties. The R-band light curve showed an initial rise followed by a single power-law decay, while the X-ray light curve was described by a single power-law decay plus a flare-like feature. Our analysis shows that the observed temporal evolution cannot be described by the external shock model in which the X-ray and optical emission are produced by the same emission mechanism. No significant color changes in multi-band light curves and a reasonable value of the initial Lorentz factor (Gamma(0) = 275 +/- 20) in a uniform interstellar medium support the afterglow onset scenario as the correct interpretation for the early R band rise. The result suggests that the optical flux is dominated by afterglow. Our further investigations show that the X-ray flux could be created by an additional feature related to energy injection and X-ray afterglow. Different theoretical interpretations indicate the additional feature in X-ray can be explained by either late internal dissipation or local inverse-Compton scattering in the external shock.

gamma-ray burst: individual (GRB 071112C)

Astronomy. Space sciences [ 440 ]

eng

IOP Publishing Ltd

(c) 2012. The American Astronomical Society. All rights reserved.

[ISSN] 0004-637X

[DOI] 10.1088/0004-637X/748/1/44

[NCID] AA00553242

[DOI] http://dx.doi.org/10.1088/0004-637X/748/1/44