{
  "bibcode": "2016GCN.19828....1S",
  "body": "V. Savchenko (APC, Paris, France) , C. Ferrigno (ISDC, University of \nGeneva, CH), P. Ubertini, A. Bazzano, L. Natalucci (INAF IAPS-Roma, \nItaly), S. Mereghetti (INAF IASF-Milano, Italy), P. Laurent (CEA, \nSaclay, France), E. Kuulkers (ESAC/ESA, Madrid, Spain)\n\nUsing INTEGRAL/SPI-ACS we have performed a search for a prompt gamma-ray \ncounterpart of the cosmic neutrino candidate IceCube HESE 128340 58537957.\n\nAt the time of the event (2016-08-14 21:45:54 UTC, hereafter T0), \nINTEGRAL/SPI-ACS was operating in the nominal mode. The spacecraft was \npointing in the direction of Norma Arm Region, and the neutrino \nlocalization was at an angle of 47.3 deg with respect to the pointing \naxis. This orientation enables high response of SPI-ACS.\n\nThe background within +/-7000 seconds around the event was very stable, \nwith only low-significance variations at 100 second time scale.\n\nWe estimate a 3-sigma upper limit on the 75-2000 keV fluence of \n3.1x10^-7 erg/cm^2 for a burst lasting less than 1 s with a \ncharacteristic short GRB spectrum (an exponentially cut off power law \nwith alpha=-0.5 and Ep=500 keV) occurring at any time in the interval \n+/-1000 s around T0.\n\nFor a typical long GRB spectrum (Band function with alpha=-1, beta=-2.5, \nand Ep=250 keV), the derived peak flux upper limit is ~1.9x10^-7 \nerg/cm^2/s at 1 s time scale in 75-2000 keV energy range.\n\nThe SPI-ACS light curves, binned at 50 ms, are derived from 91 \nindependent detectors with different lower energy thresholds (mainly \nbetween 50 keV and 150 keV) and an upper threshold at about 100 MeV.\n\nINTEGRAL has performed a pointed observation of the location of IceCube \nHESE 128340 58537957, starting 36 hours after the event. The results of \nthis observation will be reported separately.",
  "circularId": 19828,
  "createdOn": 1471781081000,
  "email": "savchenk@in2p3.fr",
  "subject": "INTEGRAL/SPI-ACS observation of IceCube HESE 128340 58537957",
  "submitter": "Volodymyr Savchenko at ISDC,U of Geneve  <savchenk@in2p3.fr>"
}