{
  "bibcode": "2017GCN.20856....1S",
  "body": "V. Savchenko, C. Ferrigno (ISDC, University of Geneva, CH),\nP. Ubertini, A. Bazzano, L. Natalucci (INAF IAPS-Roma, Italy),\nS. Mereghetti (INAF IASF-Milano, Italy), P. Laurent (CEA, Saclay,\nFrance), E. Kuulkers (ESTEC/ESA, The Netherlands)\n\nUsing INTEGRAL we have performed a search for a prompt gamma-ray\ncounterpart of the cosmic neutrino candidate IceCube HESE trigger\n65274589 129281.\n\nAt the time of the event (2017-03-12 13:49:39.83 UTC, hereafter T0),\nINTEGRAL was operating in nominal mode. The neutrino localization was\nat an angle of 38 deg with respect to the spacecraft pointing axis.\nFor this orientation, the most sensitive INTEGRAL observation is\nprovided by SPI-ACS for transients of any duration and for typical GRB\nspectra, although the response of SPI-ACS in this direction is lower\nthan optimal. This orientation also implies high response of IBIS\n(PICsIT, and to lesser degree ISGRI).\n\nThe SPI-ACS background within +/- 300 seconds around the event was very\nstable: we do not detect any significant counterparts and estimate a\n3-sigma upper limit on the 75-2000 keV fluence of 4.6x10^-7 erg/cm^2\nfor a burst lasting less than 1 s with a characteristic short GRB\nspectrum (an exponentially cut off power law with alpha=-0.5 and\nEp=500 keV) occurring at any time in the interval +/- 300 s around T0.\n\nFor a typical long GRB spectrum (Band function with alpha=-1,\nbeta=-2.5, and Ep=300 keV), the derived peak flux upper limit is\n~1.3x10^-6 erg/cm^2/s at 8 s time scale in 75-2000 keV energy range.\n\nWe have also investigated serendipitous observation by IBIS/PICsIT and\nIBIS/ISGRI. In ISGRI total count rate, we do not find any excesses\nover constant background within +/- 300 seconds around the event. In\nPICsIT spectral-timing data, we find a short (~0.4 s) excess at T0 +\n86.5 s.  It is not clear at this point if this excess can be\nclassified as a cosmic GRB or a cosmic-ray induced background effect.\nFurther investigation is ongoing.\n\nNo pointed INTEGRAL observations of the location of IceCube HESE\ntrigger 65274589 129281 have been performed or planned due to\nvisibility constraints.",
  "circularId": 20856,
  "createdOn": 1489353689000,
  "email": "savchenk@in2p3.fr",
  "subject": "INTEGRAL observation of IceCube HESE 65274589 129281",
  "submitter": "Volodymyr Savchenko at ISDC,U of Geneve  <savchenk@in2p3.fr>"
}