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GCN Circular 20936

LIGO/Virgo G277583: Fermi GBM Observations
2017-03-24T20:28:49Z (7 years ago)
Adam Goldstein at Fermi/GBM <>
Adam Goldstein (USRA) and Colleen Wilson-Hodge (NASA/MSFC) report on behalf
of the GBM-LIGO Group:
Lindy Blackburn (CfA), Michael S. Briggs (UAH), Jacob Broida (Carleton
College), Eric Burns (UAH), Jordan Camp (NASA/GSFC), Tito Dal Canton
(NASA/GSFC), Nelson Christensen (Carleton College), Valerie Connaughton
(USRA), Rachel Hamburg (UAH), C. Michelle Hui (NASA/MSFC), Pete Jenke
(UAH), Dan Kocevski (NASA/MSFC), Nicolas Leroy (LAL), Tyson Littenberg
(NASA/MSFC), Julie McEnery (NASA/GSFC), Rob Preece (UAH), Judith Racusin
(NASA/GSFC), Peter Shawhan (UMD), Karelle Siellez (GA Tech), Leo Singer
(NASA/GSFC), John Veitch (Birmingham), Peter Veres (UAH)

At the time of G277583, Fermi was passing through the South Atlantic
Anomaly, therefore the GBM detectors were disabled.

Using the Earth Occultation technique (Wilson-Hodge et al. 2012, ApJS, 201,
33) to estimate the amount of persistent emission during a 48-hour period
centered on the LIGO trigger time, we place the following range of 3-sigma
day-averaged flux upper limits based on observed sources over the entire
LIGO sky map:

Energy       min  max  median
 12- 27 keV: 0.07 0.56 0.10 Crab
 27- 50 keV: 0.13 0.84 0.17 Crab
 50-100 keV: 0.18 1.16 0.25 Crab
100-300 keV: 0.34 1.98 0.46 Crab
300-500 keV: 2.20 13.2 3.15 Crab

These limits are based on the minimum requirement that each source in the
Earth Occultation catalog was Earth-occulted at least 6 times in each of
the 24 hour periods preceding and following the LIGO trigger and that the
occultations were well separated from nearby bright sources.
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