TITLE: GCN CIRCULAR NUMBER: 35693 SUBJECT: GRB 240205B: Fermi GBM Observation DATE: 24/02/06 15:05:19 GMT FROM: Cori Fletcher at USRA <cfletcher@usra.edu> C. Fletcher (USRA) and C. Meegan (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team: "At 22:13:08.17 UT on 05 February 2024, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 240205B (trigger 728863993/240205926). which was also detected by Swift BAT (M. J. Moss et al. 2024, GCN 35683) and GECAM (W. Zhang et al. 2024, GCN 35689). The Fermi GBM Real-time Final Localization (GCN 35682) is consistent with the Swift BAT position. This burst was also independently detected by INTEGRAL SPI-ACS. The angle from the Fermi LAT boresight is 112 degrees. The GBM light curve consists of multiple peaks with a duration (T90) of about 47 s (50-300 keV). The time-averaged spectrum from T0-3.3 to T0+54.0 s is best fit by a Band function with Epeak = 34 +/- 0.8 keV, alpha = -1.69 +/- 0.02, and beta = -2.78 +/- 0.08. The event fluence (10-1000 keV) in this time interval is (4.77 +/- 0.05)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0+38 s in the 10-1000 keV band is 81.2 +/- 0.9 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/35693. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...