A Late, Infrared Flash from the Afterglow of GRB 050319

We report the detection of a bright, near-infrared flash from the afterglow of gamma-ray burst GRB 050319, 6.15 hr after the burst. The IR flash faded rapidly from J = 13.12 mag to J > 15.5 mag in about 4 minutes. There are no reported simultaneous observations at other wavelengths, thus making it a unique event. We study the implications of its late timing in the context of current theoretical models for GRB afterglows.