{
  "circularId": 40713,
  "createdOn": 1749765251730,
  "format": "text/plain",
  "submitter": "eliza.neights@gmail.com",
  "bibcode": "2025GCN.40713....1N",
  "eventId": "GRB 250612C",
  "subject": "GRB 250612C: Fermi GBM Observation",
  "submittedHow": "web",
  "body": "E. Neights (GWU, NASA GSFC) and C. Meegan (UAH) report on behalf of\nthe Fermi Gamma-ray Burst Monitor Team:\n\n\"At 14:53:16.58 UT on 12 June 2025, the Fermi Gamma-ray Burst Monitor (GBM)\ntriggered and located GRB 250612C (trigger 771432801/250612620).\nwhich was also detected by SVOM/GRM (Wang et al. 2025, GCN 40708).\n\nThe Fermi-GBM position was reported in GCN 40708 (Fermi GBM Team 2025).\n\nThe angle from the Fermi LAT boresight is 96 degrees.\n\nThe GBM light curve consists of multiple emission episodes with a duration (T90)\nof about 1.62 s (50-300 keV). The time-averaged spectrum\nfrom T0-0.128 to T0+2.688 s is best fit by\na power law function with an exponential high-energy cutoff.\nThe power law index is -0.97 +/- 0.01 and the cutoff energy,\nparameterized as Epeak, is 2110 +/- 70 keV.\n\nA Band function fits the spectrum equally well with Epeak = 2110 +/- 70 keV,\nalpha = -0.97 +/- 0.01, and beta = -4 +/- 1.\n\nThe event fluence (10-1000 keV) in this time interval is\n(2.80 +/- 0.02)E-05 erg/cm^2. The 64-ms peak photon flux measured\nstarting from T0+0.77 s in the 10-1000 keV band is 154 +/- 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/\""
}