{
  "bibcode": "2018GCN.23219....1M",
  "body": "Israel Martinez (University of Maryland) and Ignacio Taboada (Georgia Tech)\nreport on behalf of the HAWC collaboration\n(https://www.hawc-observatory.org/collaboration/):\n\nOn 2018/09/08 19:59:31.84 UT IceCube detected a track-like,\nvery-high-energy event with a high probability of being of\nastrophysical origin, at RA=144.58d and Dec=-2.13d J2000\nas reported in GCN circular 23214.\n\nThe event was not in the field of view of HAWC, so we\nanalyze the data in three timescales:\n\n*We searched for a steady source in archival data from November\n2014 to April 2018.  Assuming a spectral index of -2.5 we\nsearched in the reported 90% PSF containment circle.The maximum\nsignificance is 1.2 sigma at RA=143.9deg and Dec=-1.8deg. We\nestimate the number of trials to be ~40. We set an upper limit\n95% CL on gamma rays for this period of:\n\nE^2 dN/dE = 6.4e-13 (E/TeV)^-0.5 TeV cm^-2 s^-1.\n\n*We searched using data corresponding to the month previous\nto the IceCube-180908A alert (MJD 58340.674-58370.815). Using\nthe same spectral index and search window, the maximum significance\nis 1.0 sigma at RA=144.7deg and Dec=-2.8deg. We set an upper limit\n95% CL on gamma rays for this period of:\n\nE^2 dN/dE = 2.9e-12 (E/TeV)^-0.5 TeV cm^-2 s^-1.\n\n*We also performed a study using data corresponding to the two\nnearest transits of IceCube-180908A in HAWC���s field of view\n(MJD 58369.59-58369.81 and 58370.59-58370.81). Using the same\nspectral index and search window, the maximum significance is\n0.6 sigma at RA=145.0deg and Dec=-1.8deg. We set an upper limit\n95% CL on gamma rays for this period of:\n\nE^2 dN/dE = 1.6e-11 (E/TeV)^-0.5 TeV cm^-2 s^-1.\n\nHAWC is a very-high-energy gamma-ray observatory located in\nCentral Mexico at latitude 19 deg North. It operates 24 hours\nper day with over 95% duty cycle. HAWC has an instantaneous\nfield of view of 2 sr and surveys 2/3 of the sky every day.\nIt is sensitive to gamma rays from 300 GeV to 100 TeV.",
  "circularId": 23219,
  "createdOn": 1536627113000,
  "email": "imc@umd.edu",
  "subject": "IceCube-180908A: HAWC follow-up",
  "submitter": "Israel Martinez at HAWC  <imc@umd.edu>",
  "eventId": "IceCube-180908A"
}