TITLE: GCN GRB OBSERVATION REPORT NUMBER: 1473 SUBJECT: GRB020813: optical afterglow DATE: 02/08/13 07:57:18 GMT FROM: Weidong Li at UC Berkeley KAIT/LOSS W. D. Li, A. V. Filippenko, and R. Chornock (UC Berkeley) report on behalf of the Lick Observatory and Tenagra Observatory Supernova Search (LOTOSS): "We have observed a rectangle region of about 10' x 7' around the position of GRB020813 (HETE Trigger #2262) with the 0.8-m Katzman Automatic Imaging Telescope (KAIT) with 21 unfiltered exposures (30s, 120s and 300s) beginning on Aug 13 04:27 UT and lasted until 7:33 UT. Comparison with DSS II images identified the apparent new object reported by Fox, Blake, & Price (GCN #1470), with a precise position measured at RA = 19:46:41.89, Decl. = -19:36:04.5 (J2000). The object is also apparently fading with the following unfiltered magnitudes Aug 13 4.4625 UT, mag 17.75 Aug 13 4.5200 UT, mag 17.77 Aug 13 4.7786 UT, mag 17.82 Aug 13 5.9683 UT, mag 18.10 Aug 13 7.5550 UT, mag 18.42 We therefore strongly suggest that this is the afterglow of GRB020813. This photometry sequence is consistent with a power law of index -0.6. A finding chart of the object can be found at http://astron.berkeley.edu/~weidong/grb020813.gif." This message may be cited.