TITLE: GCN CIRCULAR NUMBER: 14765 SUBJECT: GRB 130604B: Fermi GBM detection DATE: 13/06/04 18:03:38 GMT FROM: Andrew Collazzi at NASA/MSFC/ORAU Andrew C. Collazzi (NASA/ORAU) reports on behalf of the Fermi GBM Team: "At 00:48:11.32 UT on 4 June 2013, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 130604B (trigger 391999694 / 130604.033). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 292.18, Dec = -24.86 (J2000 degrees, equivalent to J2000 19h 28m, -24d 51'), with a statistical uncertainty of 1.2 degrees (radius, 1-sigma containment, statistical only; there is additionally a systematic error which is currently estimated to be 2 to 3 degrees). The angle from the Fermi LAT boresight is 93 degrees. The GBM light curve shows a multi-peak burst with a duration (T90) of about 27 s (50 - 300 keV). The time-averaged spectrum from T0-8.192 to T0+35.841 s is well fit by a Comptonized spectrum with Epeak = 227.6 +/- 19.0 and alpha = -1.24 +/- 0.03. The fluence (10-1000 keV) in this time interval is (1.79 +/- 0.06)E-05 erg/cm^2. The burst has a 1.024-s peak flux (10-1000 keV) of 13.24 +/- 0.37 ph/cm^2/s that starts at T+15.744 s. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."