GCN Circular 2594
GRB 040511: Second Epoch Optical Observations Nidia Morrell (Las Campanas Observatory), Hsiao-Wen Chen (MIT), Joshua S. Bloom (Harvard/CfA), Jason X. Prochaska (UCO/Lick), A. Dullighan, G. Ricker, N. Butler, and R. Vanderspek (MIT): "We have obtained a second epoch of R-band images of the field around GRB 040511 (Dullinghan et al., GCN #2588) using the SITe#3 CCD imager on the 40 inch Swope telescope at the Las Campanas Observatory. The observations were carried out starting at 01:30 UT 13 May 2004 (~36 hours after the burst). Three exposures of 600 sec duration were taken under photometric and sub-arcsec seeing conditions. The 5-sigma depth of the stacked image is R~23.6 mag over a 2"-diameter aperture. A comparison of the stacked image with the first-epoch images obtained at ~11 hr after the burst (Chen et al., GCN #2591) shows that none of the ~7100 sources of Rc <~ 23 in the 14.8' x 20' region have variability by more than 0.25 mag. The few larger-amplitude outliers in the magnitude (epoch1) vs. magnitude (epoch2) plot are due to detector artifacts." The magnitude-magnitude plot that shows the comparison of object photometry obtained from two epochs and all the imaging data are publicly available at http://www.graasp.org/. Click the "Data" link. This message may be cited.