{
  "bibcode": "2005GCN..4265....1S",
  "body": "Pablo Saz Parkinson (UC Santa Cruz) on behalf of the Milagro collaboration\nreports:\n\nWe have searched Milagro data for emission at GeV/TeV energies from GRB\n051109A (GCN Circ 4213, G. Tagliaferri et al.), during the burst duration\n(36 s) reported by the Swift team (GCN Circ 4217, E. Fenimore et al.).\nNo evidence for prompt GeV/TeV emission was found. A preliminary analysis,\nassuming a differential photon spectral index of -2.4, gives an upper\nlimit on E^2dN/dE at 99% confidence of:\n\nE^2dN/dE at 2.5 TeV < 8.4 * 10^(-8) erg cm^(-2) (No EBL absorption assumed)\n\nThe spectrum of the host galaxy of the proposed afterglow of GRB 051109A\nimplies a redshift of 2.346 (GCN Circ 4221, R. Quimby et al.). TeV photons\nare attenuated by pair production with infrared photons in intergalactic\nspace so we also calculate upper limits assuming different extragalactic\ninfrared background light (EBL) absorption models, one by Kneiske et al.\n2004 (A&A 413, 807) and one by Primack et al. 2005 (AIP Conf. Proc. 745,\np.  23).  We find 99% confidence level upper limits on E^2dN/dE of:\n\nE^2dN/dE at 55 GeV < 1.7 * 10^(-3) erg cm^(-2) (Primack et al. EBL model)\nE^2dN/dE at 60 GeV < 2.3 * 10^(-4) erg cm^(-2) (Kneiske et al. EBL model)\n\nThe energies quoted represent the approximate median energy of the events\nthat would be detected assuming a power law spectrum with differential\nindex -2.4 convolved with each of the absorption models. These upper\nlimits are preliminary and will be refined with further analysis.",
  "circularId": 4265,
  "createdOn": 1131747485000,
  "email": "pablo@scipp.ucsc.edu",
  "subject": "GRB 051109A Milagro GeV/TeV Observations",
  "submitter": "Pablo Saz Parkinson at UCSC/Milagro  <pablo@scipp.ucsc.edu>",
  "eventId": "GRB 051109A"
}