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GCN Circular 33766

GRB 230510A: Fermi GBM detection
2023-05-11T08:36:05Z (a year ago)
R. Hamburg at CNRS/IJCLab <>
C. Malacaria (ISSI) and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:

"At 12:04:06.93 UT on 10 April 2023, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 230510A (trigger 705413051 / 230510503), which
was also detected by the Swift/BAT and Swift/XRT (Eyles-Ferris et al. 2023,
GCN 33752; Evans et al. 2023, GCN 33756). The GBM on-ground location is
consistent with the Swift position (GCN 33751).

The angle from the Fermi LAT boresight at the GBM trigger time is 14

The GBM light curve shows a weaker peak followed about 100 s later
by a brighter peak, with a duration (T90) of about 177 s (50-300 keV).
The time-averaged spectrum from T0-4.1 s to T0+11.3 s is
best fit by a power law function with an exponential
high-energy cutoff. The power law index is -0.9 +/- 0.1 and
the cutoff energy, parameterized as Epeak, is 87 +/- 7 keV.
A Band function fits the spectrum equally well
with Epeak = 87 +/- 9 keV, alpha = -0.9 +/- 0.1 and beta = -3.8 +/- 3.2.

The event fluence (10-1000 keV) in this time interval is
(2.0 +/- 0.1)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+158 s in the 10-1000 keV band
is 12.4 +/- 0.4 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog:

For Fermi GBM data and info, please visit the official Fermi GBM Support

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