{
  "bibcode": "2020GCN.26937....1A",
  "body": "M. Axelsson (KTH & Stockholm Univ.), F. Longo (University and INFN,  \nTrieste), M. Kovacevic (INFN Perugia), E. Bissaldi (Politecnico & INFN  \nBari), D. Kocevski (NASA/MSFC), N. Omodei (Stanford Univ.) and M.  \nArimoto (Kanazawa University) report on behalf of the Fermi-LAT  \nCollaboration:\n\nWe have searched data collected by the Fermi Large Area Telescope  \n(LAT) on January 29, 2020, for possible high-energy (E > 100 MeV)  \ngamma-ray emission in spatial/temporal coincidence with the LIGO/Virgo  \ntrigger S200129m (GCN 26926).\n\nWe define \"instantaneous coverage\" as the integral over the region of  \nthe LIGO probability map that is within the LAT field of view at a  \ngiven time, and \"cumulative coverage\" as the integral of the  \ninstantaneous coverage over time. At the time of the trigger (T0 =  \n2020-01-29 06:54:58.435 UTC), no part of the LIGO probability map was  \nobservable by Fermi-LAT. The region entered the LAT field of view  \naround T0 + 3 ks, and 100% cumulative coverage was reached after ~8.8  \nks.\n\nWe performed a search for a transient counterpart within the observed  \nregion of the 90% contour of LIGO map in a fixed time window from T0 +  \n3 ks to T0 + 10 ks. No significant new sources were found.\n\nWe also performed a search which adapted the time interval of the  \nanalysis to the exposure of each region of the sky, and no additional  \nexcesses were found.\n\nEnergy flux upper bounds for the fixed time interval between 100 MeV  \nand 1 GeV for this search vary between 2.9e-10 and 7.1e-10 [erg/cm^2/s].\n\nThe Fermi-LAT point of contact for this event is Makoto Arimoto  \n(arimoto@se.kanazawa-u.ac.jp)\n\nThe Fermi-LAT is a pair conversion telescope designed to cover the  \nenergy band from 20 MeV to greater than 300 GeV. It is the product of  \nan international collaboration between NASA and DOE in the U.S. and  \nmany scientific institutions across France, Italy, Japan and Sweden.",
  "circularId": 26937,
  "createdOn": 1580327970000,
  "email": "Milos.Kovacevic@pg.infn.it",
  "subject": "LIGO/Virgo S200129m: No counterpart candidates in Fermi-LAT observations",
  "submitter": "Milos Kovacevic at INFN Perugia  <Milos.Kovacevic@pg.infn.it>",
  "eventId": "LIGO/Virgo S200129m"
}