Sloan Digital Sky Survey multicolor observations of GRB 010222

The discovery of an optical counterpart to GRB 010222 (detected by BeppoSAX ) was announced 4.4 hr after the burst by Henden. The Sloan Digital Sky Sur vey's 0.5 m photometric telescope (PT) and 2.5 m survey telescope were used to observe the afterglow of GRB 010222 starting 4.8 hr after the gamma-ray burst. The 0.5 m PT observed the afterglow in five 300 s g*-band exposures over the course of half an hour, measuring a temporal decay rate in this s hort period of F-v proportional to t(-1.0 +/-0.5). The 2.5 m camera imaged the counterpart nearly simultaneously in five filters (u*, g*, r*, i*, z*), with r* = 18.74 +/- 0.02 at 12:10 UT. These multicolor observations, corre cted for reddening and the afterglow's temporal decay, are well-fitted by t he power law F-v proportional to v(-0.90 +/-0.03) with the exception of the u*-band UV flux which is 20% below this slope. We examine possible interpr etations of this spectral shape, including source extinction in a star-form ing region.