{
  "bibcode": "2006GCN..5527....1S",
  "body": "Pablo Saz Parkinson (UC Santa Cruz) on behalf of the Milagro\ncollaboration reports:\n\nWe have searched Milagro data for emission at GeV/TeV energies from the\nbright GRB 060904A detected by Swift (GCN Circ 5502, D. Rupe et al.),\nduring the main period of emission lasting 80s (GCN Circ 5516, H. Krimm et\nal.). No evidence for prompt GeV/TeV emission was found. A preliminary\nanalysis, assuming a differential photon spectral index of -2.4, gives an\nupper limit on E^2dN/dE at 99% confidence of:\n\nE^2dN/dE at 2 TeV < 2.9 * 10^(-7) erg cm^(-2) (No EBL absorption)\n\nTeV photons are attenuated by pair production with infrared photons in\nintergalactic space. We calculate an upper limit assuming a\nredshift of 0.5 using the extragalactic infrared background light (EBL)\nabsorption model of Primack et al. 2005 (AIP Conf. Proc. 745, p. 23).\nWe find 99% confidence level upper limits on E^2dN/dE of:\n\nE^2dN/dE at 200 GeV < 5.5 * 10^(-5) erg cm^(-2) (Primack et al. EBL model)\n\nThe energies quoted represent the approximate median energy of the\nevents that would be detected assuming a power law spectrum with\ndifferential index -2.4 convolved with the absorption model.\nThese upper limits are preliminary and will be refined with further\nanalysis.",
  "circularId": 5527,
  "createdOn": 1157479066000,
  "email": "pablo@scipp.ucsc.edu",
  "subject": "GRB 060904A Milagro GeV/TeV Observations",
  "submitter": "Pablo Saz Parkinson at UCSC/Milagro  <pablo@scipp.ucsc.edu>",
  "eventId": "GRB 060904A"
}