{
  "eventId": "GRB 260617A",
  "createdOn": 1781759928275,
  "format": "text/plain",
  "body": "Matt Godwin (UAH) and C. Meegan (UAH) report on behalf of\nthe Fermi Gamma-ray Burst Monitor Team:\n\n\"At 21:36:43.68 UT on 17 June 2026, the Fermi Gamma-ray Burst Monitor (GBM)\ntriggered and located GRB 260617A (trigger 803425008/260617900).\n\nThe on-ground calculated location, using the Fermi GBM trigger data,\nis RA = 224.34, Dec = -12.61 (J2000 degrees, equivalent to\nJ2000 15h 47m, -16d 43'), with a statistical uncertainty of 7.08 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 99 degrees.\n\nThe GBM light curve consists of a short, bright burst with a duration (T90)\nof about 0.14 s (50-300 keV). The time-averaged spectrum\nfrom T0-0.08 to T0+0.259 s is best fit by\na power law function with an exponential high-energy cutoff.\nThe power law index is -0.56 +/- 0.04 and the cutoff energy,\nparameterized as Epeak, is 700 +/- 40 keV.\n\nThe event fluence (10-1000 keV) in this time interval is\n(7.4 +/- 0.5)E-07 erg/cm^2. The 64-ms peak photon flux measured\nstarting from T0+0.0 s in the 10-1000 keV band is 21 +/- 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",
  "subject": "GRB 260617A: Fermi GBM Detection",
  "submitter": "Matt Godwin <msg0028@uah.edu>",
  "bibcode": "2026GCN.44972....1G",
  "circularId": 44972
}