TITLE: GCN CIRCULAR NUMBER: 35778 SUBJECT: GRB 240222A: Fermi GBM Observation DATE: 24/02/22 23:39:37 GMT FROM: Joe Mangan at IJCLab <joseph.mangan@ijclab.in2p3.fr> J. Mangan (CNRS/IJCLab) and C. Meegan (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team: "At 08:51:31.47 UT on 22 February 2024, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 240222A (trigger 730284696/240222369). which was also detected by Swift BAT (P. D'Avanzo et al. 2024, GCN 35770). The Fermi GBM on-ground location is consistent with the Swift BAT position. The angle from the Fermi LAT boresight is 109 degrees. The GBM light curve consists of a single emission episode with a duration (T90) of about 3.8 s (50-300 keV). The time-averaged spectrum from T0-5.9 to T0+3.3 s is best fit by a simple power law function with index -1.4 +/- 0.1. The event fluence (10-1000 keV) in this time interval is (9.2 +/- 1.9)E-07 erg/cm^2. The 1-sec peak photon flux measured starting from T0-0.19 s in the 10-1000 keV band is 4 +/- 0.7 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/35778. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...