GCN Circular 33785

S. Bala (USRA), O.J. Roberts (USRA/NASA-MSFC), B. Mailyan (Florida Tech) and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:

"At 06:27:45.00 UT on 12 May 2023, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 230512A (trigger 705565670 /230512269), which was also
detected by the Fermi/LAT (D. J. Maheso et al. 2023, GCN 33780).

The Fermi GBM Final Real-time Localization (GCN 33778) is consistent with the LAT position.

The angle from the Fermi LAT boresight at the GBM trigger time is 45 degrees.

The GBM light curve consists of multiple short peaks
with a duration (T90) of about 3 s (50-300 keV).
The time-averaged spectrum from T0-0.064 s to T0+2.944 s is
best fit by a power law function with an exponential
high-energy cutoff. The power law index is -0.67 +/- 0.02 and
the cutoff energy, parameterized as Epeak, is 1344 +/- 69 keV

The event fluence (10-1000 keV) in this time interval is
(1.33 +/- 0.02)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+1.54 s in the 10-1000 keV band
is 16.8 +/- 0.3 ph/s/cm^2.

A Band function fits the spectrum equally well
with Epeak= 1215 +/- 79 keV, alpha = -0.65 +/- 0.03 and beta = -2.7 +/- 0.2.

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/"