TITLE: GCN CIRCULAR NUMBER: 21438 SUBJECT: LIGO/Virgo G296853: Fermi GBM Observations DATE: 17/08/09 17:03:59 GMT FROM: Adam Goldstein at Fermi/GBM A. Goldstein (USRA) reports on behalf of the GBM-LIGO Group: L. Blackburn (CfA), M. S. Briggs (UAH), J. Broida (Carleton College), E. Burns (NASA/GSFC), J. Camp (NASA/GSFC), T. Dal Canton (NASA/GSFC), N. Christensen (Carleton College), V. Connaughton (USRA), R. Hamburg (UAH), C. M. Hui (NASA/MSFC), P. Jenke (UAH), D. Kocevski (NASA/MSFC), N. Leroy (LAL), T. Littenberg (NASA/MSFC), J. McEnery (NASA/GSFC), R. Preece (UAH), J. Racusin (NASA/GSFC), P. Shawhan (UMD), K. Siellez (GATech), L. Singer (NASA/GSFC), J. Veitch (Birmingham), P. Veres (UAH), C. Wilson-Hodge (NASA/MSFC) At the G296853 event time, GBM was taking data and viewing the entire un-occulted sky approximately 67 degrees from Earth center (RA = 66.9, DEC = +23.4), which includes 49% of the LIGO Bayestar probability map. There was a single GBM on-board trigger within 1 hour after the event time. However, this trigger was likely due to a terrestrial gamma-ray flash and unrelated to the G296853 event. The untargeted ground-based search of GBM data for short-duration GRBs (Briggs et al., in prep) found a low-reliability short GRB candidate ~76 minutes after the G296853 event time, although the localization of this candidate is entirely inconsistent with the Bayestar map. The targeted search of the GBM data ([1], [2]) also did not find a significant gamma-ray signal. This search processes time scales of 0.256 to 8.192 s within 30 s of the LIGO event. No interesting gamma-ray candidate was found within this time window. Further analysis and upper limits will be reported later. [1] L. Blackburn et al. 2015, ApjS 217, 8 [2] A. Goldstein et al. arXiv:1612.02395