TITLE:   GCN CIRCULAR
NUMBER:  27859
SUBJECT: GRB 200529A: Fermi GBM Detection
DATE:    20/05/29 16:50:37 GMT
FROM:    Oliver J Roberts at USRA/NASA  <oliver.roberts@nasa.gov>

O.J. Roberts (USRA) and C. Meegan (UAH) report on behalf of
the Fermi GBM Team:

"At 00:56:39.28 UT on May 29th 2020, the Fermi 
Gamma-Ray Burst Monitor (GBM) triggered and located 
GRB 200529A (trigger 612406604 / 200529039) which was 
also detected by the Swift (V. D'Elia et al. 2020, GCN 27845). 
The Fermi GBM Final Real-time Localization (GCN 27844) 
is consistent with the Swift position.

The angle from the Fermi LAT boresight at the GBM trigger time 
is 77 degrees.

The GBM light curve shows multiple peaks with a duration 
(T90) of about 85 s (50-300 keV). The time-averaged spectrum 
from T0-3.5 s to T0+81.5 s is best fit by a power law function 
with an exponential high-energy cutoff. 
The power law index is -1.34 (+0.16/-0.15) and the cutoff 
energy, parameterized as Epeak, is 73.99 (+11.10/-8.18) keV.

The event fluence (10-1000 keV) in this time interval is
(4.08 +/- 0.27)E-06 erg/cm^2. The 1-sec peak photon flux 
Measured starting from T0+17.8 s in the 10-1000 keV band
is 2.7 +/- 0.2 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog:
https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html

For Fermi GBM data and info, please visit the official Fermi GBM 
Support Page: https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/"