TITLE:   GCN CIRCULAR
NUMBER:  37660
SUBJECT: GRB 240930B: Fermi GBM Observation 
DATE:    24/10/01 19:59:50 GMT
FROM:    Jacob Smith at Fermi-GBM Team <jrs0118@uah.edu>

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

At 17:18:02 UT on 30 Sep 2024, the Fermi Gamma-ray Burst Monitor (GBM) 
triggered and located GRB 240930B (trigger 749409487 / 240930721),
and was detected by Einstein Probe Wide-field X-ray Telescope (EP-WXT) (X. Tian et al. 2024, GCN 37648), 
Einstein Probe Follow-up X-ray Telescope (EP-FXT) (H. L. Peng et al. 2024, GCN 37653), 
and Swift-BAT (J. DeLaunay et al. 2024, GCN 37654).
The Fermi GBM on-ground location is consistent with the EP-WXT, EP-FXT, and Swift-BAT localizations.

The angle from the Fermi LAT boresight is 113 degrees.

The GBM light curve single emission episode with a duration (T90)
of about 64.3 s (50-300 keV). The time-averaged spectrum
from T0-9.7 to T0+74.2 s is best fit by
a Band function
with Epeak = 86 +/- 10 keV, alpha = -0.70 +/- 0.14,
and beta = -2.03 +/- 0.06.

The event fluence (10-1000 keV) in this time interval is
(1.7 +/- 0.06)E-05 erg/cm^2. The 1.024-s peak photon flux measured
starting from T0+3.3 s in the 10-1000 keV band is 9.2 +/- 0.4 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/