C. M. Hui (NASA-MSFC) and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:
At 14:42:09.78 UT on 20 July 2019, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 190720A (trigger 585326534/190720613).
The on-ground calculated location, using the GBM trigger
data, is RA = 202.72 , DEC = +41.78 (J2000 degrees,
equivalent to 13h 30m, +41d 42.0'), with an uncertainty
of 1.16 degrees (radius, 1-sigma containment, statistical only;
there is additionally a systematic error which we have characterized
as a core-plus-tail model, with 90% of GRBs having a 3.7 deg error
and a small tail suffering a larger than 10 deg systematic error
[Connaughton et al. 2015, ApJS, 216, 32] ).
The angle from the Fermi LAT boresight is 59.00 degrees.
The GBM light curve shows/consists of single peak
with a duration (T90) of about 6.1s (50-300 keV).
The time-averaged spectrum from T0-0.0s to T0+8.8s is
adequately fit by a Band function with Epeak = 182 +/- 6 keV,
alpha = -0.89 +/- 0.02, and beta = -2.21 +/- 0.04.
The event fluence (10-1000 keV) in this time interval is
(2.74 +/- 0.03)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+2.5s in the 10-1000 keV band is 48.2 +/- 0.5 ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog:
For Fermi GBM data and info,
please visit the official Fermi GBM Support Page: