{
  "bibcode": "2017GCN.21699....1S",
  "body": "V. Savchenko (ISDC, University of Geneva, CH)\non behalf of the INTEGRAL group:\nS. Mereghetti (IASF-Milano, Italy),\nC. Ferrigno ((ISDC, University of Geneva, CH),\nE. Kuulkers (ESTEC/ESA, The Netherlands),\nA. Bazzano (IAPS-Roma, Italy), E. Bozzo,\nT. J.-L. Courvoisier (ISDC, University of Geneva, CH)\nS. Brandt (DTU - Denmark) R. Diehl (MPE-Garching, Germany)\nL. Hanlon (UCD, Ireland) P. Laurent (APC, Saclay/CEA, France)\nA. Lutovinov (IKI, Russia) J.P. Roques (IRAP, France)\nR. Sunyaev (IKI, Russia) P. Ubertini (IAPS-Roma, Italy)\n\nWe investigated serendipitous INTEGRAL observations carried out at the\ntime of the LIGO/Virgo GW event candidate G299232.  The satellite was\npointing at RA=262.993 Dec=-27.052, near the lower-probability arc of\nLIGO/Virgo localization. About 10% of LIGO localization probability\nwas in IBIS and SPI FoV. Depending on the location within LIGO 90%\nconfidence region the best upper limit is set by the anti-coincidence\nshield of the spectrometer on board of INTEGRAL (SPI/ACS), IBIS/ISGRI,\nor IBIS/PICsIT. A fraction of the localization of G299232 is not\noptimal for SPI-ACS observation.\n\nThe INTEGRAL IBAS automatically inspects both ISGRI Field of View and\nall-sky SPI-ACS light curve. It did not reveal any significant excess\nabove the background.\n\nWe investigated the SPI-ACS, IBIS/PICsIT, and IBIS/ISGRI light curves\nbetween -500 and +500 s from the trigger time (2017-08-25 13:13:37\nUTC) on temporal scales from 0.1 to 100 s, and found no evidence for\nany significant deviation from the background.  We estimate a median\n3-sigma upper limits in 90% LIGO localization region of 1.0e-6 erg/cm2\n(75-2000 keV) assuming a duration of 8s and Band model parameters\nalpha=-1, beta=-2.5, and E_ peak = 300 keV.  To derive a limit for a\ntypical short burst with 1 s duration, we use a harder cutoff power\nlaw spectrum with a photon index of -0.5 and an Epeak = 500 keV. We\nfind a median limiting fluence of 3.6e-7 erg/cm2 (75-2000 keV) at 3\nsigma c.l.\n\nFor the fraction of LIGO/Virgo localization probability within the Field of\nView of INTEGRAL pointing instruments (IBIS, JEM-X, and SPI), the\ncombination of these instruments allows to set stringent upper\nlimit in a broad energy range from 3 keV to 8 MeV (Savchenko et al\n2017 A&A...603A..46S).  Further analysis of these data is ongoing.",
  "circularId": 21699,
  "createdOn": 1503680810000,
  "email": "savchenk@apc.in2p3.fr",
  "subject": "LIGO/Virgo G299232: INTEGRAL search for a prompt gamma-ray counterpart",
  "submitter": "Volodymyr Savchenko at APC,Paris  <savchenk@apc.in2p3.fr>",
  "eventId": "LIGO/Virgo G299232"
}