TITLE: GCN CIRCULAR NUMBER: 38265 SUBJECT: GRB 241117A: Fermi GBM Detection DATE: 24/11/17 20:47:14 GMT FROM: Lorenzo Scotton at UAH lscottongcn@outlook.com
L. Scotton (UAH) and C. Meegan (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team:
"At 03:00:43.23 UT on 17 November 2024, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 241117A (trigger 753505248/241117125).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 2.04, Dec = 16.33 (J2000 degrees, equivalent to J2000 0h 8m, +16d 19'), with a statistical uncertainty of 1.74 degrees. (radius, 1-sigma containment, statistical only; there is additionally a systematic error which we have characterized as a mixture of two Gaussians, one with a radius of 1.8 degrees (52% contribution) and one with a radius of 4.1 degrees (47% contribution) [A. Goldstein et al. 2020, ApJ, 895, 1]).
The angle from the Fermi LAT boresight is 58 degrees.
The GBM light curve consists of a single emission episode with a duration (T90) of about 8.9 s (50-300 keV). The time-averaged spectrum from T0-0.3 to T0+9.86 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.46 +/- 0.07 and the cutoff energy, parameterized as Epeak, is 724 +/- 62 keV.
The event fluence (10-1000 keV) in this time interval is (9.7 +/- 0.2)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0+0.58 s in the 10-1000 keV band is 13.2 +/- 0.3 ph/s/cm^2.
A Band function fits the spectrum equally well with Epeak = 708 +/- 68 keV, alpha = -0.45 +/- 0.07 and beta = -3.16 +/- 0.98.
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/"
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