TITLE: GCN CIRCULAR NUMBER: 42259 SUBJECT: GRB 251013C: Fermi GBM Observation DATE: 25/10/14 15:35:36 GMT FROM: Jacob Smith at Fermi-GBM Team jrs0118@uah.edu
Jacob Smith (UAH), E. Palafox (INAOE), and C. Meegan (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team:
"At 17:39:41.94 UT on 13 October 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 251013C (trigger 782069986/251013736), which was also detected by SVOM (N. A. Rakotondrainibe et al. 2025, GCN 42222) and Swift XRT (P.A. Evans et al. 2025, GCN 42232). The Fermi GBM on-ground location is consistent with the Swift BAT position. NOT measured a spectroscopic redshift z = 0.572 (A. Martin-Carrillo et al. 2025, GCN 42227).
The angle from the Fermi LAT boresight is 60 degrees.
The GBM light curve consists of a single emission episode with a duration (T90) of about 12 s (50-300 keV). The time-averaged spectrum from T0-0.1 to T0+4.0 s is best fit by a simple power law function with index -1.50 +/- 0.02. A Comptonized function fits equally well with Epeak = 7291.00 +/- 4840.00 and alpha = -1.46 +/- 0.03.
The event fluence (10-1000 keV) in this time interval is (2.4 +/- 0.1)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0+0.32 s in the 10-1000 keV band is 5 +/- 0.2 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/"
View this GCN Circular online at https://gcn.nasa.gov/circulars/42259. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...