TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3913 SUBJECT: GRB 050904: SOAR/PROMPT Observations DATE: 05/09/04 10:00:28 GMT FROM: Daniel E. Reichart at U.North Carolina J. Haislip, D. Reichart, E. Cypriano, S. Pizzaro, A. LaCluyze, J. Rhoads, E. Figueredo report on behalf of the UNC team of the FUN GRB Collaboration. We imaged the XRT localization of GRB 050904 (Cummings et al., GCN 3910) with 4.1m SOAR at CTIO beginning about three hours after the burst. We detect a relatively bright (J ~ 17.5 mag) and fading source within the XRT error circle: RA: 00 54 51.3 DEC 14 05 09.7 There is no source at this location in POSS2 or SDSS. Near-simultaneous imaging with PROMPT reveals no source to about the POSS2 detection limit. This suggests that the afterglow is either very extinguished or at high redshift.