TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4636 SUBJECT: GRB 060202: Optical Afterglow Candidate from Keck/LRIS DATE: 06/02/03 09:23:20 GMT FROM: S. Bradley Cenko at Caltech S. B. Cenko, D.-S. Moon, (Caltech), and B. P. Schmidt (MSO-ANU) report on behalf of a larger collaboration: We have imaged the field GRB060202 (Fox et al., GCN 4629) with the Low-Resolution Imaging Spectrometer mounted on the 10-m Keck I telescope. Observations consisted of 2 x 300 s images taken simultaneously in the g and I filters at a mean time of approximately February 3.22. Images were taken under good seeing conditions, though shortly after sunset with a high background. Inside the revised XRT error circle (Morris et al., GCN 4632), we find one faint source (S1) in our I-band images detected at approximately the 2-sigma level. The location of this source is (J2000): RA: 02:23:22.88 Dec: +38:23:04.3 with an approximate error of 1.0" in each coordinate. The magnitude of this object, with reference to the USNO-B2 catalog, is approximately I = 22.6 +/- 0.3, with photometric calibration dominating the errors. We find no source in our g-band coadd at this location to a limiting magnitude of approximately g > 22.0. We note this position is consistent with the detection of a K-band source with UKIRT by Wang et al. (private communication, GCN forthcoming). There is one additional source (S2), of similar magnitude and color, located just outside the edge of the XRT error circle, which we include for completeness. The location of this source (J2000.0) is: RA: 02:23:22.80 Dec: +38:23:08.9 While we cannot comment on variability at this time, we propose that the source S1 is the afterglow of GRB 060202. The early R-band limits provided by Monfardini et al. (GCN 4630) indicate a red R-I color for this potential afterglow. Given the possibility that this object is at high redshift (z > 5), we have triggered Gemini NIR imaging of the field. A report on these observations will follow in a subsequent GCN.