{
  "format": "text/plain",
  "submitter": "sumanbala2210@gmail.com",
  "circularId": 39133,
  "createdOn": 1738603345776,
  "bibcode": "2025GCN.39133....1B",
  "eventId": "GRB 250202B",
  "submittedHow": "web",
  "body": "S. Bala (USRA) reports on behalf of the Fermi Gamma-ray Burst Monitor Team:\n\n\"At 03:57:17.32 UT on 02 February 2025, the Fermi Gamma-ray Burst Monitor (GBM)\ntriggered and located GRB 250202B (trigger 760161442/250202165).\n\nThe on-ground calculated location, using the Fermi GBM trigger data,\nis RA = 347.80, Dec = 16.48 (J2000 degrees, equivalent to\nJ2000 23h 11m, +16d 29'), with a statistical uncertainty of 1.43 degrees.\n(radius, 1-sigma containment, statistical only; there is additionally a\nsystematic error which we have characterized as a mixture of two Gaussians,\none with a radius of 1.8 degrees (52% contribution) and one with a radius\nof 4.1 degrees (47% contribution) [A. Goldstein et al. 2020, ApJ, 895, 1]).\n\nThe angle from the Fermi LAT boresight is 128 degrees.\n\nThe GBM light curve consists of many bright peaks with a duration (T90)\nof about 89 s (50-300 keV). The time-averaged spectrum\nfrom T0-0.1 to T0+109.4 s is best fit by\na Band function with Epeak = 252 +/- 5 keV,\nalpha = -0.81 +/- 0.01, and beta = -2.56 +/- 0.05.\n\nThe event fluence (10-1000 keV) in this time interval is\n(1.77 +/- 0.01)E-04 erg/cm^2. The 1-sec peak photon flux measured\nstarting from T0+1.7 s in the 10-1000 keV band is 43.4 +/- 0.7 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/\"",
  "subject": "GRB 250202B: Fermi GBM Detection"
}