{
  "bibcode": "2025GCN.38887....1P",
  "eventId": "GRB 250109A",
  "body": "U. Pathak (IITB) and C. Meegan (UAH) report on behalf of\nthe Fermi Gamma-ray Burst Monitor Team:\n\n\"At 06:17:08.60 UT on 09 January 2025, the Fermi Gamma-ray Burst Monitor (GBM)\ntriggered and located GRB 250109A (trigger 758096233/250109262).\nwhich was also detected by EP-WXT and EP-FXT (Li et al. 2025, GCN 38864).\nThe Fermi GBM on-ground location is consistent with the EP-FXT position.\nA possible optical counterpart was also detected by SVOM/VT (Qiu et al. 2025, GCN 38872).\n\nThe angle from the Fermi LAT boresight is 72 degrees.\n\nThe GBM light curve consists of multiple weak spikes from a single emission episode \nwith a duration (T90) of about 15 s (50-300 keV). The time-averaged spectrum\nfrom T0-8.2 to T0+9.2 s is best fit by a power law function. \nThe power law index is -1.57 +/- 0.05.\n\nThe event fluence (10-1000 keV) in this time interval is\n(1.9 +/- 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 1.3 +/- 0.2 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/\"",
  "format": "text/plain",
  "submitter": "Utkarsh Pathak at IIT Bombay <utkarshpathak.07@gmail.com>",
  "circularId": 38887,
  "subject": "GRB 250109A: Fermi GBM Observation",
  "createdOn": 1736491217203,
  "submittedHow": "web"
}