{
  "bibcode": "2016GCN.19360....1V",
  "body": "G.Vianello (Stanford), J. D. Magill (UMD/GSFC), N. Omodei (Stanford), D.\nKocevski (NASA/Goddard), M. Ajello (Clemson), S. Buson (NASA/GSFC), F.\nKrauss (ECAP/FAU), J. Chiang (SLAC/Kipac)\n\nreport on behalf of the Fermi-LAT team:\n\nWe have searched the Fermi Large Area Telescope data for a high-energy\ngamma-ray counterpart for the IceCube High Energy Starting Event (HESE)\n67093193, detected in run 127853 on 2016-04-27 05:52:32.00 UT (AMON GCN\nnotice rev. 2, http://gcn.gsfc.nasa.gov/notices_amon/67093193_127853.amon.\nSee http://gcn.gsfc.nasa.gov/doc/Public_Doc_AMON_IceCube_GCN_Alerts_v2.pdf\nfor a description of HESE events and related GCN notices).\n\nThe localization region was outside the LAT field of view at the time of\nthe detection by IceCube (T0). It entered the LAT FoV at ~T0 + 6140 s and\nexited again at ~T0 + 8420 s. We ran the standard GRB search (Vianello et\nal. 2015) plus an ad-hoc search for a counterpart in this time interval and\nin 10 h intervals before and after the event. We found no significant\ntransient candidate associated with the neutrino event.\n\nThe Automated Science Processing search, which looks for variation in flux\nfrom known sources and for new transients on different time scales (Chiang\n2012), did not detect any transient or flaring source consistent with the\nIceCube event position during the six-hour intervals before and after the\nneutrino detection time, nor during the day before and after the event.\n\nThe Fermi All-Sky Variability Analysis (FAVA), a photometric analysis\ncurrently designed to detect variable sources on one-week timescales, did\nnot find any excess emission consistent with the most current\nlocalization.  Likewise, an examination of previous weeks analyzed by\nthis technique reveals no long timescale flaring sources compatible with\nthe localization region.\n\nThe 90% containment provided by IceCube, which is ~36 arcmin wide, contains\nno LAT source from the Fermi Point Source catalog (3FGL, Acero et al.\n2015). The 5 closest sources are all blazars:\n\nSource name       | Distance | Association           | Blazar Type |\n--------------------------------------------------------------------\n3FGL J1603.7+1106 | 108'     | MG1 J160340+1106      | BL Lac      |\n3FGL J1608.6+1029 | 117'     | 4C +10.45             | FSRQ        |\n3FGL J1555.7+1111 | 147'     | PG 1553+113           | BL Lac      |\n3FGL J1552.1+0852 | 153'     | TXS 1549+089          | BL Lac      |\n3FGL J1546.0+0818 | 249'     | 1RXS J154604.6+081912 | BL Lac      |\n\nWe note in particular that PG 1553+113 has been detected in high state on\n2016-04-27 in the 0.3-10 keV band by the Swift X-ray Telescope (B.\nKapanadze, ATel #8998, http://www.astronomerstelegram.org/?read=8998),\nalthough we do not detect any significant change in flux above 100 MeV.\n\nThe Fermi-LAT points of contact for this event are Giacomo Vianello (Burst\nAdvocate, giacomov@stanford.edu) and Jeffrey D Magill (Flare Advocate,\njmagill@umd.edu).\n\nThe Fermi-LAT is a pair conversion telescope designed to cover the energy\nband from 20 MeV to greater than 300 GeV. It is the product of an\ninternational collaboration between NASA and DOE in the U.S. and many\nscientific institutions across France, Italy, Japan and Sweden.",
  "circularId": 19360,
  "createdOn": 1461883127000,
  "email": "giacomov@slac.stanford.edu",
  "subject": "Fermi/LAT search for counterpart to the IceCube event 67093193 (run 127853)",
  "submitter": "Giacomo Vianello at SLAC  <giacomov@slac.stanford.edu>"
}