TITLE: GCN CIRCULAR NUMBER: 26727 SUBJECT: LIGO/Virgo 200112r: No counterpart candidates in Fermi-LAT observations DATE: 20/01/13 09:24:41 GMT FROM: Francesco Longo at U of Trieste,INFN Trieste F. Longo (University and INFN, Trieste), D. Kocevski (NASA/MSFC) and M. Arimoto (Kanazawa Univ.) report on behalf of the Fermi-LAT Collaboration: We have searched data collected by the Fermi Large Area Telescope (LAT) on January 12th, 2020, for possible high-energy (E > 100 MeV) gamma-ray emission in spatial/temporal coincidence with the LIGO/Virgo trigger S200112r (GCN 26715). We define "instantaneous coverage" as the integral over the region of the LIGO probability map that is within the LAT field of view at a given time, and "cumulative coverage" as the integral of the instantaneous coverage over time. Fermi-LAT was in SAA at the time of the trigger of the event (T0 =2020-01-12 15:58:38.094 UTC), started to observe the LIGO probability region around 1.8 ks later with an instantaneous coverage of 30% and reached 100% cumulative coverage of the LIGO probability after about 10 ks. We performed a search for a transient counterpart within the observed region of the 90% contour of LIGO map in a fixed time window from T0 +1.8 ks to T0 + 10 ks. Two significant excess (with TS>25) were found. The first one at R.A., Dec. = 215.8, 32.4 is likely associated with the known and currently active source OQ 334, the second one at R.A., Dec. = 57.2, -27.8 is instead likely associate with the source PKS 0346–27, also currently active. We also performed a search which adapted the time interval of the analysis to the exposure of each region of the sky, and no additional excesses were found. Energy flux upper bounds for the fixed time interval between 100 MeV and 1 GeV for this search vary between 1.6e-10 and 4.3e-07 [erg/cm^2/s]. The Fermi-LAT point of contact for this event is F.Longo (francesco.longo@ts.infn.it). The Fermi-LAT is a pair conversion telescope designed to cover the energy band from 20 MeV to greater than 300 GeV It is the product of an international collaboration between NASA and DOE in the U.S. and many scientific institutions across France, Italy, Japan and Sweden.