TITLE:   GCN CIRCULAR
NUMBER:  30738
SUBJECT: GRB 210827A: Fermi GBM Observation
DATE:    21/08/28 23:58:01 GMT
FROM:    Suraj Poolakkil at UAH  <sp0076@uah.edu>

S. Lesage (UAH), R. Dunwoody (UCD), J. Mangan (UCD) and C. Meegan (UAH)
report on behalf of
the Fermi Gamma-ray Burst Monitor Team:

"At 09:59:24 UT on 27 August 2021, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 210827A (trigger 651751169/210827416)
which was also detected by Swift/BAT-GUANO (James DeLaunay et al. 2021, GCN
30732).
The Fermi GBM Final Real-time Localization (GCN 30724) is consistent with
the Swift/BAT-GUANO position.

The angle from the Fermi LAT boresight is 42 degrees.

The GBM light curve consists of a single emission episode with a duration
(T90)
of about 9 s (10-1000 keV). The time-averaged spectrum
from T0-2.0 to T0+4.1 s is best fit by
a simple power law function with index -1.6 +/- 0.1.

The event fluence (10-1000 keV) in this time interval is
(7 +/- 1)E-07 erg/cm^2. The 1-sec peak photon flux measured
starting from T0-2.5 s in the 10-1000 keV band is 1.7 +/- 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/"