Difference: GCNCIRCULAR217011 ( vs. 1)

LIGO/VIRGO G299232: Fermi GBM Observations

R. Hamburg (UAH) 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), A. Goldstein (USRA), 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 G299232 event time (2017-08-25 13:13:37 UTC), Fermi GBM was taking data and viewing the entire un-occulted sky approximately 67 degrees from Earth center (RA = 54.6,Dec = 7.8), which includes 36% of the LIGO BAYESTAR HLV map.

No on-board triggers occurred within an hour of the GW trigger time. The untargeted ground-based search of GBM data for short-duration GRBs (Briggs et al., in prep) also did not find any significant candidate within one hour of the GW trigger.

The targeted search of the GBM data ([1],[2]) searched +/- 30 s around the GW event time, processing time scales of 0.256 to 8.192 s. One event with a soft spectrum was found on a 4 s timescale approximately 27 s after the GW time. The initial estimated False Alarm Rate (FAR) is 4.6e-4 Hz (90% confidence). The localization returned by the search does not overlap with the LHV Bayestar localization region. We conclude that this signal is unassociated with the GW event.

The targeted search was also run +/- 30 s around the gamma-ray candidate reported by AGILE MCAL (Carrillo et al., 2017, GCN 21700). No significant candidates were found.

[1] L. Blackburn et al. 2015, ApJS 217, 8
[2] A. Goldstein et al. arXiv:1612.02395

-- ShaonGhosh - 27 Aug 2017