TITLE:   GCN CIRCULAR
NUMBER:  35755
SUBJECT: GRB 240218A: Fermi GBM Detection
DATE:    24/02/19 01:21:14 GMT
FROM:    Peter Veres at University of Alabama in Huntsville <veresp@gmail.com>

P. Veres and C. Meegan (both UAH) report on behalf of
the Fermi Gamma-ray Burst Monitor Team:

"At 02:00:21.72 UT on 18 February 2024, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 240218A (trigger 729914426/240218084),
which was also detected by Swift/BAT (Page et al. 2024, GCN 35742). 
The Fermi GBM on-ground localization is consistent with the Swift BAT position.


The angle from the Fermi LAT boresight is 93 degrees.

The GBM light curve consists of a single pulse followed by weaker emission with a duration (T90)
of about 38 s (50-300 keV). The time-averaged spectrum
from T0-2.6 to T0+30.2 s is best fit by
a Band function with Epeak = 100 +/- 20 keV,
alpha = -0.3 +/- 0.3, and beta = -1.9 +/- 0.1.

The event fluence (10-1000 keV) in this time interval is
(5.2 +/- 0.4)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+1.5 s in the 10-1000 keV band is 3.1 +/- 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/"