{
  "format": "text/plain",
  "subject": "GRB 250609A: Fermi GBM Observation",
  "createdOn": 1749549585195,
  "submitter": "Christian Malacaria at INAF-OAR <cmalacaria.astro@gmail.com>",
  "bibcode": "2025GCN.40664....1M",
  "circularId": 40664,
  "body": "C. Malacaria (ISSI) and C. Meegan (UAH) report on behalf of\nthe Fermi Gamma-ray Burst Monitor Team:\n\n\"At 08:47:18.61 UT on 09 June 2025, the Fermi Gamma-ray Burst Monitor (GBM)\ntriggered and located GRB 250609A (trigger 771151643/250609366).\nwhich was also detected by Swift/BAT-GUANO (DeLaunay et al. 2025, GCN 40658).\nThe Fermi GBM on-ground location was reported by the Fermi-GBM team in GCN 40652.\n\nThe angle from the Fermi LAT boresight is 81 degrees.\n\nThe GBM light curve consists of a single emission episode with a duration (T90)\nof about 1 s (50-300 keV). The time-averaged spectrum\nfrom T0-5.5 to T0+1.7 s is best fit by\na simple power law function with index -1.3 +/- 0.1.\n\nThe event fluence (10-1000 keV) in this time interval is\n(4.5 +/- 0.9)E-07 erg/cm^2. The 64-ms peak photon flux measured\nstarting from T0-0.13 s in the 10-1000 keV band is 4 +/- 1 ph/s/cm^2.\n\nThe spectral analysis results presented above are preliminary;\nfinal results will be published in the GBM GRB Catalog:\nhttps://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html\n\nFor Fermi GBM data and info, please visit the official Fermi GBM Support Page:\nhttps://fermi.gsfc.nasa.gov/ssc/data/access/gbm/\"",
  "submittedHow": "web",
  "eventId": "GRB 250609A"
}