TITLE: GCN CIRCULAR NUMBER: 29314 SUBJECT: Correction to GCN 29288: NuEm-210111A: No counterpart candidates in INTEGRAL SPI-ACS observation DATE: 21/01/17 18:55:51 GMT FROM: Volodymyr Savchenko at ISDC,U of Geneve V. Savchenko (ISDC/UniGE, Switzerland) on behalf of the INTEGRAL multi-messenger collaboration: https://www.astro.unige.ch/cdci/integral-multimessenger-collaboration Standard INTEGRAL search for counterparts of NuEm-210111A, based on association with short event with known time is not adequate in this case since the precise time of the NuEm-210111A event is not reported in GCN 29287. Suitable search for any counterparts of NuEm-210111A in INTEGRAL data is within the known event time interval is provided below. We apologise for the confusion. ===== Using INTEGRAL data we have performed a search for a prompt gamma-ray counterpart of NuEm-210111A (GCN 29287). In the time interval corresponding to the event, between the 2021-01-11 06:47:00 and 2021-01-11 13:06:41 UT, INTEGRAL was operating in nominal mode and continiously collecting data. The event localization probability was at angles from 85 to 92 deg with respect to the spacecraft pointing axis, yielding stable response of all INTEGRAL instruments throughout the entire time interval of interest. This orientation implies strongly suppressed (~15% of optimal) response of ISGRI, strongly suppressed (~35% of optimal) response of IBIS/Veto, and near-optimal (~70% of optimal) response of SPI-ACS. Since in this case, SPI-ACS is the most sensitive to the flux from the NuEm-210111A among INTEGRAL instruments, we only report analysis of its data. In the region of interest, the background was rather stable (typical excess variance 1.2). We have performed a search for any impulsive events in INTEGRAL SPI- ACS data (following [1]), and did not find any relevant bursts. We estimate a 3-sigma upper limit on the 75-2000 keV fluence of 2.6e-07 erg/cm^2 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 ~2.2e-07 (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. 2012, A&A 541A, 122S --