{
  "bibcode": "2021GCN.30147....1M",
  "body": "C. Malacaria (USRA) and C. Meegan (UAH)\nreport on behalf of the Fermi GBM Team:\n\n\"At 22:40:25.32 UT on 6 June 2021, the Fermi Gamma-Ray Burst Monitor (GBM)\ntriggered and located GRB 210606B (trigger 644712030 / 210606945).\nThis burst was also independently detected by INTEGRAL SPI-ACS,\nGECAM (GCN 30138) and AGILE (GCN 30142).\n\nThe on-ground calculated location, using the GBM trigger\ndata, is RA = 87.48, DEC = -18.41 (J2000 degrees,\nequivalent to 05 h 49 m, -18 d 24 '), with a statistical uncertainty\nof 1.20 degrees (radius, 1-sigma containment,\nstatistical only; there is additionally a systematic\nerror which we have characterized as a core-plus-tail model, with 90% of\nGRBs having a 3.7 deg error and a small tail suffering a larger than 10 deg\nsystematic error. [Connaughton et al. 2015, ApJS, 216, 32] ).\n\nThe angle from the Fermi LAT boresight at the GBM trigger time is 82 degrees.\n\nThe GBM light curve consists of three main peaks\ntaking place about 40 s after the initial trigger,\nplus one weaker peak showing 250 s after the initial trigger.\nThe full event has a duration (T90) of about 244 s (50-300 keV).\n\nThe time-averaged spectrum from T0+42 s to T0+52 s is\nbest fit by a power law function with an exponential\nhigh-energy cutoff. The power law index is -1.04 +/- 0.01 and\nthe cutoff energy, parameterized as Epeak, is 397 +/- 13 keV.\nA Band function fits the spectrum equally well\nwith Epeak= 394 +/- 14 keV, alpha = -1.04 +/- 0.01 and beta = -3.7 +/- 1.5 .\n\nThe event fluence (10-1000 keV) in this time interval is\n(3.45 +/- 0.04)E-05 erg/cm^2. The 1-sec peak photon flux measured\nstarting from T0+49 s in the 10-1000 keV band\nis 35.6 +/- 0.4 ph/s/cm^2.\n\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": 30147,
  "createdOn": 1623103921000,
  "email": "cmalacaria@usra.edu",
  "subject": "GRB 210606B: Fermi GBM detection",
  "submitter": "Christian Malacaria at NASA-MSFC/USRA  <cmalacaria@usra.edu>",
  "eventId": "GRB 210606B"
}