TITLE:   GCN CIRCULAR
NUMBER:  35899
SUBJECT: GRB 240306A: Fermi GBM observation
DATE:    24/03/07 15:53:40 GMT
FROM:    Elisabetta Bissaldi at Politecnico and INFN Bari <elisabetta.bissaldi@ba.infn.it>

E. Bissaldi (Politecnico and INFN Bari) and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:

"At 06:45:50.21 UT on 06 March 2024, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 240306A (trigger 731400355 / 240306282),
which was also detected by the Swift/BAT GUANO (Parsotan et al. 2024, GCN 35889),
AstroSat CZTI (Joshi et al. 2024, GCN 35892) and INTEGRAL SPI-ACS (trigger 10616).

The GBM localization was reported in an earlier GCN (Fermi GBM Team, GCN 35885).

The angle from the Fermi LAT boresight at the GBM trigger time is 87 degrees.

The GBM light curve consists of single pulse 
with a duration (T90) of about 9 s (50-300 keV).
The time-averaged spectrum from T0-1.7 s to T0+7.7 s is
best fit by a power law function with an exponential
high-energy cutoff. The power law index is -1.16 +/- 0.07 and
the cutoff energy, parameterized as Epeak, is 135 +/- 12 keV.

The event fluence (10-1000 keV) in this time interval is
(3.15 +/- 0.14)E-06 erg/cm^2. The 1-sec peak photon flux 
measured starting from T0+0.6 s in the 10-1000 keV band
is 6.8 +/- 0.3 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/"