[vsnet-grb-info 18799] INTEGRAL SPI-ACS and IBIS/Veto observation of IceCube-161210

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  20249
SUBJECT: INTEGRAL SPI-ACS and IBIS/Veto observation of IceCube-161210
DATE:    16/12/11 15:50:29 GMT
FROM:    Volodymyr Savchenko at ISDC,U of Geneve  <savchenk at in2p3.fr>

V. Savchenko (APC, Paris, France) , C. Ferrigno (ISDC, University of
Geneva, CH), P. Ubertini, A. Bazzano, L. Natalucci (INAF IAPS-Roma,
Italy), S. Mereghetti (INAF IASF-Milano, Italy), P. Laurent (CEA,
Saclay, France), E. Kuulkers (ESAC/ESA, Madrid, Spain)

Using INTEGRAL SPI-ACS and IBIS/Veto we have performed a search
for a prompt gamma-ray counterpart of the cosmic neutrino candidate
IceCube-161210 (GCN 20247).

At the time of the event (2016-12-10 20:07:16 UTC, hereafter T0),
INTEGRAL was operating in nominal mode. The neutrino localization
was at an angle of 136 deg with respect to the spacecraft pointing axis.
This orientation implies moderately suppressed response of SPI-ACS,
the response of IBIS/Veto was close to optimal.
The best sensitivity to  bursts longer than 8 s was achieved by IBIS/Veto,
to those shorter - by SPI-ACS.

The background within ±300 seconds around the event was very stable.
However, 139 seconds after T0 INTEGRAL/SPI-ACS detected a short excess
in a single bin (50 ms), consistent with the properties of the excesses
produced in SPI-ACS by cosmic ray interactions.

We do not detect any significant counterparts and estimate a 3-sigma
upper limit on the 75-2000 keV fluence of 4.6x10^-7erg/cm^2for a burst
lasting less than 1 s with a characteristic short GRB spectrum
(an exponentially cut off power law with alpha=-0.5 and Ep=500 keV)
occurring at any time in the interval ±300 s around T0.

For a typical long GRB spectrum (Band function with alpha=-1, beta=-2.5,
and Ep=250 keV), the derived peak flux upper limit is ~4.5x10^-7(6.2x10^-7)
erg/cm^2/s at 1 s (8 s) time scale in 75-2000 keV energy range.

No pointed INTEGRAL observations of the location of IceCube-161103 have 
been
performed or planned due to visibility constraints.