{
  "bibcode": "2022GCN.32288....1R",
  "body": "O.J. Roberts (USRA/NASA), B. Hristov (UAH) and C. Meegan (UAH) report\non behalf of the Fermi Gamma-ray Burst Monitor Team:\n\n\"At 21:21:00.09 UT on 27 June 2022, the Fermi Gamma-ray Burst Monitor\n(GBM) triggered and located GRB 220627A (trigger 678057665/220627890)\nwhich was also detected by the LAT (N. Di Lalla, et al. 2022, GCN 32283)\nand observed by Swift-BAT-GUANO (G. Raman, et al. 2022, GCN 32287).\n\nThe Fermi GBM Final Real-time Localization (GCN 32278) is consistent\nwith the LAT position.\n\nThe angle from the Fermi LAT boresight is 27 degrees.\n\nThe GBM light curve shows multiple bursts over a duration (T90) of\nabout 138 s (10-1000 keV).\n\nThe time-averaged spectrum for the this burst from T0-5 s to T0+289 s\nis best fit by a power law function with an exponential high-energy\ncutoff. The power law index is -0.83 +/- 0.02 and the cutoff energy,\nparameterized as Epeak, is 410 +/- 16 keV. The event fluence (10-1000 keV)\nin this time interval is (7.88 +/- 0.13)E-05 erg/cm^2.\n\nA Band function fits the spectrum equally well with Epeak= 390 +/- 20 keV,\nalpha = -0.81 +/- 0.03 and beta = -2.68 +/- 0.31.\n\nThe 1-sec peak photon flux measured starting from T0+171.1 s in the\n10-1000 keV band is 5.1 +/- 0.2 ph/s/cm^2.\n\nSeparately, about 1000 s later at 21:36:56.39 UT, GBM triggered on\n678058621/220627901, which localized to a similar location of\nRA: 207.02 deg. Dec: -28.48 deg. (J2000 degrees, equivalent to\nJ2000 13h 48m, +/- 28d 28'), with a statistical uncertainty of 1.2 degrees\n(radius, 1-sigma containment, statistical only; there is additionally a\nsystematic error which we have characterized as a core-plus-tail model,\nwith 90% of GRBs having a 3.7 deg error and a small tail suffering a larger\nthan 10 deg systematic error. [Connaughton et al. 2015, ApJS, 216, 32] ).\n\nWe find the T90 of this multiple pulsed burst of similar shape, to be\n127 s (10-1000 keV). The time-averaged spectrum for the this burst\nfrom T0-47 s to T0+122 s is best fit by a power law function with an\nexponential high-energy cutoff. The power law index is -1.12 +/- 0.04 and\nthe cutoff energy, parameterized as Epeak, is 227 +/- 15 keV. The event\nfluence (10-1000 keV) in this time interval is (2.47 +/- 0.08)E-05 erg/cm^2.\n\nThe 1-sec peak photon flux measured starting from T0+113.2 s in the\n10-1000 keV band is 3.5 +/- 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/\"",
  "circularId": 32288,
  "createdOn": 1656447776000,
  "email": "oliver.roberts@nasa.gov",
  "subject": "GRB 220627A: Fermi GBM Detection of a possible Lensed or Ultra-long GRB",
  "submitter": "Oliver J Roberts at USRA/NASA  <oliver.roberts@nasa.gov>",
  "eventId": "GRB 220627A"
}