{
  "bibcode": "2009GCN..9829....1C",
  "body": "Valerie Connaughton (UAH) reports on behalf of the Fermi GBM Team:\n\n\"At 00:38:16.19 UT on 20 August 2009, the Fermi Gamma-Ray Burst Monitor\ntriggered and located GRB 090820027 (trigger 272421498 / 090820027).\n\nThe on-ground calculated location, using the GBM trigger\ndata, is RA = 87.7, DEC = 27.0 (J2000 degrees,\nequivalent to 05h 51 m, 27 d 00 '), with an uncertainty\nof 1.0 degrees (radius, 1-sigma containment, statistical only;\nthere is additionally a systematic error which is currently estimated\nto be 2 to 3 degrees).\n \nThe angle from the Fermi LAT boresight is 108 degrees.\n\nAlthough this burst was bright enough to result in a Fermi spacecraft\nrepointing maneuver and ensuing pointed observations of the burst\nposition, Earth avoidance constraints prevented such a maneuver\nuntil 3100 sec after the burst trigger.\n\nThe light curve shows GBM triggered on a weak precursor,\nfollowed by a bright pulse beginning 30 s later and lasting a\nfurther 30 s.  The time-averaged spectrum from T0+28 s to T0+60 s\nis best fit by a Band function with Epeak = 215 +/- 3 keV,\nalpha = -0.69  +/- 0.01, and beta = -2.61 - 0.05.\n\nThe event fluence (8-1000 keV) in this time interval is\n(6.6 +/- 0.1)E-5 erg/cm^2. The 1-sec peak photon flux measured\nstarting from T0+34 s in the 8-1000 keV band\nis about 58 ph/s/cm^2.\n\nThe spectral analysis results presented above are preliminary;\nfinal results will be published in the GBM GRB Catalog.\"",
  "circularId": 9829,
  "createdOn": 1250751495000,
  "email": "valerie@nasa.gov",
  "subject": "GRB 090820: Fermi GBM Detection of a bright burst.",
  "submitter": "Valerie Connaughton at MSFC  <valerie@nasa.gov>",
  "eventId": "GRB 090820"
}