TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3438 SUBJECT: GRB 050520: P200 Observations DATE: 05/05/20 14:59:28 GMT FROM: S. Bradley Cenko at Caltech S. Bradley Cenko, Derek B. Fox, S. R. Kulkarni, Naveen Reddy, Dawn Erb, David Law, and Chuck Steidel report on behalf of the Caltech-NRAO-Carnegie GRB collaboration: We have imaged the field of GRB 050520 (Gotz et al., GCN 3430) with the Wide Field Infrared Camera (WIRC) mounted on the Palomar 200" Hale Telescope. Observations consisted of 27 dithered frames for a total integration time of 22.5 minutes at a mean epoch of approximately 6:35 UT (6.5 hours after the burst). All images were taken in the Ks filter. We find no sources inside the XRT error circle (Kennea et al, GCN 3434). Our limiting magnitude, estimated by comparison with the 2mass object 12501123+3027515 (Ks = 15.42), is approximately Ks > 20.0. However, we do find two faint sources just outside the XRT error circle. Their coordinates (J2000.0) and approximate magnitudes are: RA Dec Distance from XRT Ks ------------------------------------------------------------------------- 12:50:06.0 30:27:06.7 5.8" 19.3 12:50:06.3 30:26:55.1 7.8" 19.1 Both sources are too faint to search for variability in our exposures.