GCN Circular 20532
Subject
LIGO/Virgo G270580: Fermi GBM Observations
Date
2017-01-26T17:36:20Z (8 years ago)
From
Adam Goldstein at Fermi/GBM <adam.michael.goldstein@gmail.com>
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)
As mentioned by Kocevski et al. (GCN 20499), Fermi was passing through the
South Atlantic Anomaly at the time of the LIGO trigger, and 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: 0.09 0.34 0.11 Crab
27- 50 keV: 0.13 0.42 0.17 Crab
50-100 keV: 0.20 0.70 0.26 Crab
100-300 keV: 0.32 1.28 0.43 Crab
300-500 keV: 2.58 13.2 3.64 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.