////////////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19787 SUBJECT: IceCube 160806A EHE Neutrino Candidate Event DATE: 16/08/09 16:15:58 GMT FROM: Doug Cowen at Penn State/IceCube D.F. Cowen reports on behalf of the IceCube Collaboration: IceCube detected a candidate cosmic neutrino IceCube-160806A, "AMON ICECUBE EHE 128311 26552458" at 12:21:33.00 UT on 16/08/06 (http://gcn.gsfc.nasa.gov/notices_amon/26552458_128311.amon) The event was an Extremely High Energy (EHE) event with track-like characteristics and it arrived when the IceCube detector was in a normal operating state. EHE events satisfy a combination of high light level and zenith angle that enhances astrophysical signal relative to cosmic-ray-induced backgrounds. In contrast to the other active IceCube high energy track-like neutrino alert stream, known as "HESE," EHE events are not required to start within the IceCube detector fiducial volume. After the initial automated alert, more sophisticated reconstruction algorithms have been applied offline, with the direction refined to RA=122.81d and DEC=-0.8061d (J2000) in revision 1 of this alert. The position uncertainty is estimated from the initial realtime reconstruction from revision 0 of this alert, at 0.1 degrees or 6.7 arcminutes radius (stat. only, 50% containment). Lacking inclusion of systematic effects, we expect this uncertainty underestimates the true uncertainty by roughly a factor of five. We encourage followup by ground and space-based instruments to help identify a possible astrophysical source for the candidate neutrino. The IceCube Neutrino Observatory is a cubic-kilometer neutrino detector operating at the geographic South Pole, Antarctica. The IceCube realtime alert point of contact can be reached at roc@icecube.wisc.edu ////////////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19789 SUBJECT: INTEGRAL/SPI-ACS and IBIS_VETO search for prompt gamma-ray counterpart of IceCube-160806A DATE: 16/08/10 16:40:10 GMT FROM: Volodymyr Savchenko at ISDC,U of Geneve V. Savchenko (APC, Paris, France) , C. Ferrigno (ISDC, University of Geneva, CH), P. Ubertini, A. Bazzano, L. Natalucci (IAPS-Roma, Italy), S. Mereghetti (IASF-Milano, Italy), P. Laurent (CEA, Saclay, France), E. Kuulkers (ESAC/ESA, Madrid, Spain) Using INTEGRAL/SPI-ACS and INTEGRAL/IBIS VETO we have performed a search for prompt gamma-ray counterpart of cosmic neutrino candidate IceCube-160806A (Cowen 2016, GCN 19787). At the time of the event (2016-08-06T12:21:33 UTC, hereafter T0), INTEGRAL IBIS was operating in the nominal mode. INTEGRAL/SPI was finishing the annealing cycle: at this stage of the procedure it has no effect on SPI-ACS. The spacecraft was pointing in the direction of Norma Arm Region, and the neutrino localization was at 110 deg angle with respect to the pointing axis. This orientation enables high response of both SPI-ACS and IBIS_VETO. The nearest confirmed GRB (GRB160806A), was triggered by INTEGRAL/SPI-ACS at 2016-08-06 14:00:57, 1h 40m after the event. This GRB is also detected in the IBIS_VETO light curve. SPI-ACS and IBIS_VETO (bottom) light-curves around the time of the neutrino candidate event can be found at: http://isdc.unige.ch/~savchenk/IceCube-160806A/ The count rate data around the event reveals variability, including smooth background instabilities as well as burst-like events. Several burst-like excesses can be seen, most prominent ones at T0+50s, T-150s, T0-2000s, and T0-10000s. Ratio of SPI-ACS to IBIS_VETO rates for these events is compatible with a gamma-ray source from the direction of IceCube-160806A. However, we note that these flares are coincident with GOES proton background flares. Although we can not exclude cosmic origin of some of these bursts, judging from long-lasting background instability near the region of interest, as well as the activity observed by GOES, we are inclined to conclude that these bursts are associated with background variability introduced by solar activity. We estimate a 3-sigma upper limit on fluence in 75-2000 keV energy range in the interval ±1000 s around the IceCube trigger of 3.3x10^-7 erg/cm^2 for a burst with duration less than 1 s with a characteristic short GRB spectrum (an exponentially cut off power law with alpha=-0.5 and Ep=500 keV). For a typical long GRB spectrum (the Band function with alpha=-1, beta=-2.5, and Ep=250 keV), the corresponding limiting peak flux is ~2.2x10^-7 erg/cm^2/s at 1 s time scale in 75-2000 keV energy range. The SPI-ACS light curves, binned at 50 ms, are derived from 91 independent detectors with different lower energy thresholds (mainly between 50 keV and 150 keV) and an upper threshold at about 100 MeV. The IBIS_VETO light curves, binned at 8 s, are derived from 16 independent detectors with lower energy thresholds near 80 keV and an upper threshold at about 50 MeV. Two groups of detector rates are recorded independently: bottom and lateral IBIS VETO. The response of the bottom IBIS VETO peaks in the direction opposite to satellite pointing axis, where the response of SPI-ACS is suppressed. Due to solar angle constrains, INTEGRAL can not perform pointed observation of the location of IceCube-160806A until September 22, so no pointed follow-up will be scheduled. ////////////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19791 SUBJECT: IceCube 160806A: Lomonosov BDRG gamma ray prompt observations DATE: 16/08/13 09:27:15 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs M.I.Panasyuk, S.I.Svertilov, A.V.Bogomolov, V.V.Bogomolov, A.M.Amelushkin, V.O.Barinova, A.F.Iyudin, V.V.Kalegaev, D.Nguen, V.L. Petrov, I.V.Yashin Physics Department, Skobel`tsyn Institute of Nuclear Physics, Moscow State V.Chazov, V. Lipunov, E.S. Gorbovskoy, Lomonosov Moscow State University, Sternberg Astronomical Institute I. Park, S. Jeong, M.B. Kim, S. Jeong Department of Physics, Sungkyunkwan University, Seobu-ro, Jangangu, Suwonsi, Korea A.J. Castro-Tirado Instituto de Astrofisica de Andalucia (IAA-CSIC), P.O.Box 03004, E-18080 Granada, Spain V. Reglero GACE, Edif. deCentros de Investigacion, Universidad de Valencia, Burjassot, E-46100 Valencia, Spain IceCube-160806 (Cowen, GCN 19787) was in BDRG FOV of 47 deg from the axis of the most illuminated BDRG-1 detector (Direction of BDRG-1 axis RA 05h05m08.96s DEC -25o24'44.54"). No significant GRB was detected by BDRG/Lomonosov in the interval +/-50 s from the moment of IC-160806 160806, 12:21:33. Upper limits (3 sigma) for 1 s exposition from BDRG-1 background counts: <0.23 cm-2 s-1 for 20-60 keV, <0.13 cm-2 s-1 for 60-300 keV Fermi GBM event 160806 14:01:00.00 source was out of BDRG FOV and was shadowed by Earth at 160806 14:01:00.000UT (BDRG-1 axis RA 05h14m17.069s.DEC -11o30'33.16", BDRG-2 axis RA 05h30m09.243s.DEC -78o50'16.92",BDRG-3 axis RA 11h16m39.621s.DEC -01o02'44.44"). Moren detailes information are available at: http://lomonosov.sinp.msu.ru/1081 . The message csn be cited. ////////////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19817 SUBJECT: Fermi GBM Observations of IceCube-160806A DATE: 16/08/18 00:12:24 GMT FROM: Eric Burns at U of Alabama E. Burns (UAH), A. Goldstein (USRA), P. Jenke (UAH) and L. Blackburn (CfA) report on behalf of the Fermi GBM team: We have searched the Fermi Gamma-ray Burst Monitor data for a gamma-ray counterpart to the IceCube neutrino 160806A (Cowen 2016, GCN 19787). The location of the neutrino was observed by GBM with good geometry. The closest on-board trigger was more than 90 minutes after the neutrino time and came from a different position on the sky. Measurements using the Earth Occultation technique (Wilson-Hodge et al. 2012, ApJS, 201, 33) around this position place a three sigma flux upper limit of about 160 mCrab between 12 and 100 keV between August 5th and 7th. A seeded search for impulsive emission with duration between 0.256 s and 8.192 s around the time and sky location of the detected neutrino yielded no candidates above the GBM background. The search method was developed to look for electromagnetic counterparts in the GBM data of sub-threshold gravitational wave signals found in the LIGO data (Blackburn et al. 2015, ApJS, 217, 8), and implemented here searching from 30 s before to 30 s after and seeded with the position of the detected neutrino. A blind search for untriggered impulsive emission in the GBM data centered on the neutrino detection looking for events between 0.1 s and 32 s durations yielded no candidates consistent with the position of the neutrino. This search technique was developed for the detection of untriggered short GRBs in the GBM data (Briggs et al., in prep.). There is some flaring activity from Vela X-1 around the time of interest, most notably around T0+500 seconds. This is unrelated. With no impulsive emission found we set model-dependent 1 second peak flux 3 sigma upper limits on prompt emission. Using a cutoff power law model with index -0.42 and Epeak of 566 keV, representative of a typical short GRB, the limit in the 10-1000 keV range is 9.3x10^-7 erg/cm^2/s. The INTEGRAL SPI-ACS found four intervals of burst-like excesses (Savchenko 2016, GCN 19789). Both the Sun and the neutrino location were occulted by the Earth for Fermi for the first interval. We found no evidence for the other three burst-like excesses in any detectors. Combining the SPI-ACS detection with the GBM non-detection for these three times allows us to infer that these SPI-ACS bursts are most likely due to a source occulted by the Earth for Fermi rather than a solar or neutrino source origin. //////////////////////////////////////////////////////////////////////////////