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GCN Circular 24985

Subject
LIGO/Virgo IceCube-190704A: No counterpart candidates in INTEGRAL SPI- ACS and IBIS prompt observation
Date
2019-07-05T15:13:04Z (5 years ago)
From
James Rodi at IAPS-INAF <james.rodi@inaf.it>
Celia Sanchez-Fernandez (ESA ESAC, Madrid), James Rodi  (IAPS-Roma, Italy),
V. Savchenko, C. Ferrigno (ISDC/UniGE, Switzerland)
A. Coleiro (APC, France)
S. Mereghetti (INAF IASF-Milano, Italy)

on behalf of the INTEGRAL multi-messenger collaboration:
https://www.astro.unige.ch/cdci/integral-multimessenger-collaboration

Using combination of INTEGRAL all-sky detectors (following [1]):
SPI/ACS, IBIS/Veto, and IBIS we have performed a search for a prompt
gamma-ray counterpart of IceCube-190704A (GCN 24981).

At the time of the event (2019-07-04 18:48:52 UTC, hereafter T0),
INTEGRAL was operating in nominal mode. The peak of the event
localization probability was at an angle of 95 deg with respect to the
spacecraft pointing axis. This orientation implies strongly suppressed
(7.3% of optimal) response of ISGRI, strongly suppressed (26% of
optimal) response of IBIS/Veto, and near-optimal (82% of optimal)
response of SPI-ACS.

The background within +/-300 seconds around the event was very stable
(excess variance 1.2).

We have performed a search for any impulsive events in INTEGRAL SPI-
ACS (as described in [2]), IBIS, and IBIS/Veto data.

We do not detect any significant counterparts and estimate a 3-sigma
upper limit on the 75-2000 keV fluence of 2e-07 erg/cm^2 (within the
50% probability containment region of the source localization) for 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=600 keV)
occurring at any time in the interval within 300 s around T0. For a
typical long GRB spectrum (Band function with alpha=-1, beta=-2.5, and
Ep=300 keV), the derived peak flux upper limit is ~1.8e-07 (5.8e-08)
erg/cm^2/s at 1 s (8 s) time scale in 75-2000 keV energy range.



All results quoted are preliminary.

This circular is an official product of the INTEGRAL Multi-Messenger
team.

[1] Savchenko et al. 2017, A&A 603, A46
[2] Savchenko et al. 2012, A&A 541A, 122S
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