TITLE: GCN GRB OBSERVATION REPORT NUMBER: 1497 SUBJECT: GRB020813 IRAM millimeter observations DATE: 02/08/16 13:09:35 GMT FROM: Frank Bertoldi at MPIFR/Bonn F. Bertoldi (MPIfR Bonn), D.A. Frail (NRAO), A. Weiss (IRAM Granada), K.M. Menten (MPIfR Bonn), S. Kulkarni (Caltech), E. Berger (Caltech) report: The afterglow of GRB 020813 (Fox et al., GCN 1470) was observed at 250 GHz (1.2 mm) with the 37 channel Max-Planck Millimeter Bolometer (MAMBO) array (80 GHz bandwidth, 10.7 arcsec HPBW) at the IRAM 30 m telescope on Pico Veleta (Spain), at the position reported by Rhoads et al. (GCN 1474). The observation dates, average elevations, 250 GHz zenith opacities, on-sky integration time, and (1/rms^2 weighted) average flux densities are listed in the following table: date UT EL tau_z t_int flux [mJy] ----------------------------------------------------- Aug 13, 19:10-21:10 32d 0.50 2950s 1.45 +-1.15 Aug 14, 23:10-23:55 31d 0.39 1260s 1.08 +-1.39 total: 4210s 1.30 +-0.89 Given the high line of sight opacity we were not able to detect the GRB afterglow at sufficient significance. Our flux density limits are consistent with those found by Bremer et al. (GCN 1487) at 232 GHz, -0.63 +-2.06 mJy. This message may be quoted.