IceCube200614A: No counterpart candidates in INTEGRAL SPIACS prompt observation
Abstract
Using INTEGRAL/SPIACS realtime data (following [1]) we have performed a search for a prompt gammaray counterpart of IceCube200614A (GCN 27941). At the time of the event (20200614 12:41:21 UTC, hereafter T0), INTEGRAL was operating in nominal mode. The peak of the event localization probability was at an angle of 75 deg with respect to the spacecraft pointing axis. This orientation implies strongly suppressed (15% of optimal) response of ISGRI, strongly suppressed (32% of optimal) response of IBIS/Veto, and somewhat suppressed (64% of optimal) response of SPIACS. The background within +/300 seconds around the event was very stable (excess variance 1.1). We have performed a search for any impulsive events in INTEGRAL SPI ACS (as described in [2]) data. We do not detect any significant counterparts and estimate a 3sigma upper limit on the 752000 keV fluence of 2.7e07 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 ~2.4e07 (7.1e08) erg/cm^2/s at 1 s (8 s) time scale in 752000 keV energy range. We report for completeness and in order of FAP, all excesses identified in the search region. We find 3 likely background excesses: TT0  scale  S/N  flux ( x 1e06 erg/cm2/s)  FAP 89.2  4.5  3.6  1.5 +/ 0.491 +/ 0.667  0.116 89.4  2.55  4  2.2 +/ 0.653 +/ 0.979  0.119 85.4  0.25  4.1  0.77 +/ 0.21 +/ 0.342  0.975 Note that FAP estimates (especially at timescales above 2s) may be possibly further affected by enhanced nonstationary local background noise. This list excludes any excesses for which FAP is close to unity. All results quoted are preliminary. This circular is an official product of the INTEGRAL MultiMessenger team. [1] Savchenko et al. 2017, A&A 603, A46 [2] Savchenko et al. 2012, A&A 541A, 122S
 Publication:

GRB Coordinates Network
 Pub Date:
 June 2020
 Bibcode:
 2020GCN.27952....1D