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GCN Circular 37945

Subject

GRB 241029A: Fermi GBM Observation

Date

2024-10-29T18:20:11Z (2 days ago)

From

Ava Myers at NASA GSFC <ava.myers@nasa.gov>

Via

Web form

A. Myers (NPP/GSFC), M. Godwin (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team:

At 02:19:59.87 UT on 29 October 2024, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 241029A (trigger 751861204/241029097). which was also detected by SVOM/ECLAIRs (S. Schanne et al., GCN 37934). The Fermi GBM on-ground location is consistent with the SVOM position.

The angle from the Fermi LAT boresight is 76 degrees.

The GBM light curve consists of multiple peaks with a duration (T90) of about 13.3 s (50-300 keV). The time-averaged spectrum from T0 to T0+13.152 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -1.01 +/- 0.04 and the cutoff energy, parameterized as Epeak, is 220 +/- 10 keV.

The event fluence (10-1000 keV) in this time interval is (9.2 +/- 0.3)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0-0.064 s in the 10-1000 keV band is 9.6 +/- 0.4 ph/s/cm^2.

A Band function fits the spectrum equally well with Epeak= 190 +/- 20 keV, alpha = -0.96 +/- 0.05 and beta = -2.5 +/- 0.3.

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/