Multi-color Shallow Decay and Chromatic Breaks in the GRB 050319 Optical Afterglow

Abstract

Multi-wavelength B, V, R, I observations of the optical afterglow of GRB 050319 were performed by the 1.05-m telescope at Kiso Observatory and the 1.0-m telescope at Lulin Observatory from 1.31 hours to 9.92 hours after the burst. Our R band lightcurves, combined with other published data, can be described by the smooth broken power-law function, with ${\alpha }_1$ = -0.84 $\pm$0.02 to ${\alpha }_2$ = -0.48$\pm$0.03, 0.04 days after the GRB. The optical lightcurves are characterized by shallow decays-- as was also observed in the X-rays-- which may have a similar origin, related to energy injection. However, our observations indicate that there is still a puzzle concerning the chromatic breaks in the R band lightcurve (at 0.04 days) and the X-ray lightcurve (at 0.004 days) that remains to be solved.

14 pages, 2 figures, accpeted for publication in ApJL

References in corpus (2)

• Gamma-Ray Bursts: Progress, Problems & Prospects
• A late, infrared flash from the afterglow of GRB 050319

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