{
  "eventId": "GRB 250612B",
  "bibcode": "2025GCN.40717....1S",
  "createdOn": 1749796490409,
  "format": "text/plain",
  "circularId": 40717,
  "subject": "GRB 250612B: Fermi GBM Observation",
  "submittedHow": "web",
  "body": "R. Sonawane (IISER, TVM) and C. Meegan (UAH) report on behalf of\nthe Fermi Gamma-ray Burst Monitor Team:\n\n\"At 12:27:56.19 UT on 12 June 2025, the Fermi Gamma-ray Burst Monitor (GBM)\ntriggered and located GRB 250612B (trigger 771424081/250612519).\nwhich was also detected by EP-WXT (Hua et al. 2025, GCN 40700).\nThe Fermi GBM on-ground location is consistent with the EP-WXT position.\n\nThe angle from the Fermi LAT boresight is 68 degrees.\n\nThe GBM light curve consists of single emission episode with a duration (T90)\nof about 10.8 s (50-300 keV). The time-averaged spectrum\nfrom T0-4.4 to T0+18.2 s is best fit by\na Band function with Epeak = 47.80 +/- 1.53 keV,\nalpha = -0.92 +/- 0.09, and beta = -3.47 +/- 0.39.\n\nA Comp model fits the spectrum equally well, with a power-law index = –0.98 +/- 0.07 \nand cutoff energy parameterized as Epeak = 49.14 +/- 1.26 keV.\n\nThe event fluence (10-1000 keV) in this time interval is\n(5.2 +/- 0.2)E-06 erg/cm^2. The 1-sec peak photon flux measured\nstarting from T0+2.9 s in the 10-1000 keV band is 12.1 +/- 0.3 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/\"",
  "submitter": "Rushikesh Sonawane  at IISER, TVM <rushikesh23@iisertvm.ac.in>"
}