TITLE:   GCN CIRCULAR
NUMBER:  43575
SUBJECT: GRB 260130A: Fermi GBM Detection
DATE:    26/01/31 05:10:32 GMT
FROM:    Peter Veres at University of Alabama in Huntsville <veresp@gmail.com>

A. Jameson (UAH), C. Meegan (UAH), and M. Dafčíková (MUNI) report on behalf of
the Fermi Gamma-ray Burst Monitor Team:

"At 13:29:20.82 UT on 30 January 2026, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 260130A (trigger 791472565/260130562).

The on-ground calculated location, using the Fermi GBM trigger data,
is RA = 48.70, Dec = 64.17 (J2000 degrees, equivalent to
J2000 3h 14m, +64d 10'), with a statistical uncertainty of 1.60 degrees.
(radius, 1-sigma containment, statistical only; there is additionally a
systematic error which we have characterized as a mixture of two Gaussians,
one with a radius of 1.8 degrees (52% contribution) and one with a radius
of 4.1 degrees (47% contribution) [A. Goldstein et al. 2020, ApJ, 895, 1]).

The angle from the Fermi LAT boresight is 16 degrees.

The GBM light curve consists of a single emission episode with a duration (T90)
of about 0.5 s (50-300 keV). The time-averaged spectrum
from T0-0.07 to T0+0.20 s is best fit by
a power law function with an exponential high-energy cutoff.
The power law index is -0.41 +/- 0.02 and the cutoff energy,
parameterized as Epeak, is 730 +/- 30 keV.

The event fluence (10-1000 keV) in this time interval is
(8.8 +/- 0.4)E-07 erg/cm^2. The 64-ms peak photon flux measured
starting from T0+0.0 s in the 10-1000 keV band is 27 +/- 1 ph/s/cm^2.

A Band function fits the spectrum equally well
with Epeak= 570 +/- 20 keV, alpha = -0.33 +/- 0.02 and beta = -2 +/- 0.1.


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/"