TITLE:   GCN CIRCULAR
NUMBER:  43740
SUBJECT: GRB 260212A: Fermi GBM Observation
DATE:    26/02/14 20:29:37 GMT
FROM:    eliza.neights@gmail.com

Eliza Neights (GWU, NASA GSFC) and C. Meegan (UAH) report on behalf of
the Fermi Gamma-ray Burst Monitor Team:

"At 17:49:08.21 UT on 12 February 2026, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 260212A (trigger 792611353/260212742),
which was also detected by Glowbug (Cheung et al. 2026, GCN 43719),
SVOM/GRM (Zhang et al. 2026, GCN 43727), and GECAM-B (Zhang et al. 2026, GCN 43736).

The angle from the Fermi LAT boresight is 127 degrees.

The GBM light curve consists of multiple emission episodes with a duration (T90)
of about 9.7 s (50-300 keV). The time-averaged spectrum
from T0-1.5 to T0+14.5 s is best fit by
a power law function with an exponential high-energy cutoff.
The power law index is -0.66 +/- 0.02 and the cutoff energy,
parameterized as Epeak, is 107 +/- 1 keV.

The event fluence (10-1000 keV) in this time interval is
(7.1 +/- 0.2)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+8.7 s in the 10-1000 keV band is 16.2 +/- 0.6 ph/s/cm^2.

A Band function fits the spectrum equally well
with Epeak= 90 +/- 1 keV, alpha = -0.43 +/- 0.02 and beta = -2.52 +/- 0.04.

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/"