TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3907 SUBJECT: GRB 050824: MDM Observations DATE: 05/09/02 18:31:11 GMT FROM: Jules Halpern at Columbia U. J. P. Halpern (Columbia U.) and N. Mirabal (U. Michigan) report on behalf of the MDM Observatory GRB follow-up team: "We observed the Swift GRB 050824 afterglow (Gorosabel et al., GCN #3865) in the R band on five consecutive nights using the MDM 1.3m telescope. Photometry was established using two Landolt standard-star fields on one photometric night. From 5.6 to 12.6 hours, the decay is consistent with a power law of index -0.55+/-0.05, which extrapolates well to the MASTER photometry at 24 and 47 minutes (Lipunov et al., GCN #3883). This decay index is similar to that seen in the Swift XRT light curve, -0.4+/-0.2 (Campana et al., CGN #3877), immediately preceding the MDM observations. An unobserved inflection in the optical light curve then occurs, and from 1.3 to 4.4 days the decay index is -0.43+/-0.04. Our final measured point is R=22.18+/-0.06 on Aug. 29.32. Images and light curves are posted at http://www.astro.columbia.edu/~jules/grb/050824/ This message may be cited."