1202.1356 (K. Y. Huang et al.)

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

K. Y. Huang, Y. Urata, Y. H. Tung, H. M. Lin, L. P. Xin, M. Yoshida, W. Zheng, C. Akerlof, S. Y. Wang, W. H. Ip, M. J. Lehner, F. B. Bianco, N. Kawai, D. Kuroda, S. L. Marshall, M. E. Schwamb, Y. Qiu, J. H. Wang, C. Y. Wen, J. Wei, K. Yanagisawa, Z. W. Zhang

We present the 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 \pm 20) in a uniform ISM support the afterglow onset scenario as the correct interpretation for the early R-band rise. The result suggests 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.

View original: http://arxiv.org/abs/1202.1356