TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4249 SUBJECT: GRB 051103 Milagro GeV/TeV Observations DATE: 05/11/11 06:45:36 GMT FROM: Pablo Saz Parkinson at UCSC/Milagro Pablo Saz Parkinson (UC Santa Cruz) on behalf of the Milagro Collaboration reports: We have searched Milagro data for emission at GeV/TeV energies from the IPN short hard burst GRB 051103 (GCN Circ 4197, S. Golenetskii et al.), during the 0.17 s burst duration observed by the Konus-Wind experiment. No evidence for prompt GeV/TeV emission was found. This burst occurred at a relatively large zenith angle of 50 degrees, where the sensitivity of Milagro is degraded. A preliminary analysis, assuming a differential photon spectral index of -2.4, gives an upper limit on the fluence at 99% confidence of: Fluence < 4.2 * 10^(-6) erg cm^(-2) (0.25 - 25 TeV) If the burst originated from a source in the nearby galaxy M81, at a distance of less than 4 Mpc (GCN Circ 4197, S. Golenetskii et al.) the attenuation due to the extra-galactic background light (EBL) would be negligible. This upper limit is preliminary and will be refined with further analysis.