{
  "bibcode": "2013GCN.15255....1F",
  "body": "Gerard Fitzpatrick (UCD) reports on behalf of the Fermi GBM Team:\n\nAt 04:09:26.73 UT on 25 September 2013, the Fermi Gamma-Ray Burst Monitor\ntriggered and located GRB130925A (trigger 401774969/130925173),\nwhich was also detected approximately 2 minutes later by Swift (Lien et\nal., GCN 15246). The on-ground\ncalculated location is consistent with the Swift location. The GBM data\nshow that the event\nwas still in progress at the time of the Swift trigger. The burst was\nsufficiently\nbright that a Fermi Automatic Repointing Request (ARR) was triggered. This\nevent may\nnot actually be a GRB, as indicated by Burrows et al. (GCN 15253). Downlink\nof the full data set for\nthis event was delayed due to the ARR; more details will be provided when\nthe data are available.\n\nAt 03:56:23.29 UT, 15 minutes prior to the GBM detection of GRB130925A,\nGBM triggered and located\nGBM trigger 401774186/130925164.  The on-ground calculated location, using\nthe GBM trigger\ndata, is RA = 48.3 , DEC = -21.8  (J2000 degrees,\nequivalent to 03h 13m, -21d 42.0'), with an uncertainty\nof 12.8  degrees (radius, 1-sigma containment,\nstatistical only; there is additionally a systematic\nerror which is currently estimated to be 2 to 3 degrees).\nThis is also consistent with the Swift location of GRB130925A\n(Lien et al., GCN 15246). The temporal and positional coincidence indicate\nthat this may be\na precursor pulse to GRB130925A.\n\nThe GBM light curve for this possible precursor consists of a single peak\nwith a duration (T90) of about 6.6 s (50-300 keV).\nThe time-averaged spectrum from T0-4 s to T0+2.5 s is\nadequately fit by a simple power law function with index -2.25 +/- 0.07\n\nThe event fluence (10-1000 keV) in this time interval is\n(6.9 +/- 0.6)E-07 erg/cm^2. The 1-sec peak photon flux measured\nstarting from T0-3 s in the 10-1000 keV band is 3.0 +/- 0.2 ph/s/cm^2.",
  "circularId": 15255,
  "createdOn": 1380125586000,
  "email": "gerard.fitzpatrick@ucdconnect.ie",
  "subject": "Fermi GBM detection of GRB 130925A and a possible precursor",
  "submitter": "Gerard Fitzpatrick at UCD  <gerard.fitzpatrick@ucdconnect.ie>",
  "eventId": "GRB 130925A"
}