TITLE: GCN GRB OBSERVATION REPORT NUMBER: 381 SUBJECT: GRB 990705, R-band observations DATE: 99/07/08 18:08:40 GMT FROM: Jules Halpern at Columbia U. J. Halpern (Columbia U.), G. Jacoby (NOAO), F. Frontera (ITESRE-CNR, Bologna), M. Feroci, E. Costa (IAS-CNR, Rome), and L. Piro (ITESRE-CNR, Frascati) report: "We (GJ) observed the BeppoSAX NFI error circle of GRB 990705 (Gandolfi GCN #373) in the R band using the CTIO 1.5m telescope. A 10 minute exposure was obtained on July 7.44 UT in seeing of 1.4 arcsec, and 20 minutes were obtained on July 8.42 UT in seeing of 1.6 arcsec. At precisely the position quoted for the fading infrared transient (Palazzi et al. GCN #377), we see nothing to a 3-sigma limiting magnitude of R < 22.0 on July 7, and R < 22.3 on July 8. Photometric calibration was performed using the Landolt standard field of PG 0231+051. For reference we measure R = 16.45 for the neighboring USNO-A2.0 star at RA 05:09:53.822, Dec -72:08:26.04. The nearest R-band source to the IR transient is an extended or confused object (difficult to evaluate because of the high stellar density in this field) of core magnitude R = 19.70 +/- 0.05, which is also clearly visible on the ESO Sky Survey J plate. We measure its position, (J2000) RA 05:09:55.44, Dec -72:07:58.7, with respect to 40 stars from the USNO-A2.0 catalog having an rms error of 0.45 arcsec. Since this object is 2.3 arcsec north of the infrared transient, and since the IR position was reported with an uncertainty of 1.5 arcsec, more precise astrometry of the IR image would be desirable to register it with the optical and to investigate the relationship, if any, between these objects. It seems prudent, however, to presume that there is no connection. This message may be cited."