TITLE:   GCN CIRCULAR
NUMBER:  44697
SUBJECT: GRB 260522A: Fermi GBM Observation
DATE:    26/05/23 00:32:40 GMT
FROM:    Angus Jameson <abj0023@uah.edu>

A. Jameson (UAH) reports on behalf of the Fermi Gamma-ray Burst Monitor Team:

"At 02:15:08.78 UT on 22 May 2026, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 260522A (trigger 801108913/260522094),
which was also detected by Fermi-LAT ( et al. 2026, GCN 44689).
The Fermi GBM on-ground location is consistent with the Fermi-LAT position.

The angle from the Fermi LAT boresight is 10 degrees.

The GBM light curve consists of a single emission episode with a duration (T90)
of about 1.8 s (50-300 keV). The time-averaged spectrum
from T0-0.7 to T0+0.4 s is best fit by
a power law function with an exponential high-energy cutoff.
The power law index is -0.48 +/- 0.04 and the cutoff energy,
parameterized as Epeak, is 1010 +/- 70 keV.

The event fluence (10-1000 keV) in this time interval is
(8.1 +/- 0.7)E-07 erg/cm^2. The 64-ms peak photon flux measured
starting from T0+0.51 s in the 10-1000 keV band is 3 +/- 1 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/"