TITLE: GCN CIRCULAR NUMBER: 39290 SUBJECT: GRB 250206A: Fermi GBM Observation DATE: 25/02/11 20:44:49 GMT FROM: oindabimukherjee@gmail.com
O. Mukherjee (USRA) and C. Meegan (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team:
"At 19:51:31.93 UT on 06 February 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250206A (trigger 760564296/250206827). which was also detected by Fermi-LAT (Gupta et al. 2025, GCN 39233) and Konus-Wind (Ridnaia et al. 2025, GCN 39283). The Fermi GBM on-ground location is consistent with the Fermi-LAT position.
The angle from the Fermi LAT boresight is 33 degrees.
The GBM light curve consists of a multipeaked emission episode followed by a single peaked emission episode with a duration (T90) of about 64.3 s (50-300 keV). The time-averaged spectrum from T0-2.0 to T0+79.9 s is best fit by a Band function with Epeak = 187 +/- 8 keV, alpha = -0.73 +/- 0.04, and beta = -2.6 +/- 0.2.
The event fluence (10-1000 keV) in this time interval is (2.66 +/- 0.05)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0+1.7 s in the 10-1000 keV band is 10.4 +/- 0.3 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/"
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