TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2686 SUBJECT: GRB040825A: Optical observations DATE: 04/09/01 11:30:49 GMT FROM: Brian Lindgren Jensen at U.of Copenhagen Brian L. Jensen (U. Copenhagen), Arnaud Cassan (IAP, Paris), Dijana Dominis (U. Potsdam), Jens Hjorth, Johan Fynbo (U. Copenhagen), Michael I. Andersen (AIP, Potsdam), Javier Gorosabel (IAA-CSIC, Granada) report: "We report optical observations, covering ~90% of the refined 7' error-circle (HETE#11553-2) of GRB040825A, taken with the Danish 1.54m telescope at La Silla (FoV=13.7'), as follows: Date midobs (UT) | t_b+ | filter:expt | seeing | 3sig limit ------------------------------------------------------------ Aug. 26.30, 2004 27.7h R:14x600s ~1.1" R~23.5 Aug. 26.31, 2004 27.9h V:12x600s ~1.4" V~23.3 Aug. 27.31, 2004 51.9h R:18x600s ~1.5" R~23.0 Aug. 28.28, 2004 75.2h I:13x300s ~2.1" I~21.0 Photometric calibration is based on Henden et al. (GCN#2668). Visual comparison of the three main epochs reveals no candidate optical afterglow down to R~23.0" [GCN OPS NOTE (02Sep04 11:15 UT): The second column (t_b+) of the table had a wrong offset in the original posting (should have been 12.8h larger). This archived copy of the circular has the corrected t_b+ values.]