TITLE: GCN CIRCULAR NUMBER: 11407 SUBJECT: Fermi GBM detection of a burst from a galactic source DATE: 10/11/15 16:45:48 GMT FROM: Alexander van der Horst at NASA/MSFC A.J. van der Horst (USRA) and C. Kouveliotou (NASA/MSFC) report on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 311450068 at 17:54:26.74 UT on 14 November 2010, tentatively classified as Unreliable Location, is in fact a short, soft burst from a galactic source. The on-ground location, using the GBM trigger data, is RA = 264.3, Dec = -20.9 (J2000 degrees, equivalent 17h37m to -20d52m), with an uncertainty of 5.3 degrees (radius, 1-sigma containment, statistical only; there is additionally a systematic error which is currently estimated to be 2 to 3 degrees). This location corresponds to galactic coordinates: Long = 5.88, Lat = 5.85 (J2000 degrees). The angle from the LAT boresight is 55 degrees. The GBM light curve consists of one peak with an estimated duration of 32 ms (8-1000 keV). The time-averaged spectrum from T0-0.032 s to T0 is best fit by Optically Thin Thermal Bremsstrahlung with Epeak = 28.4 +/- 2.2 keV. The event fluence (10-1000 keV) in this time interval is (5.4 +/- 0.3)E-8 erg/cm^2. The 16-ms peak photon flux measured starting from T0-0.016 s in the 10-1000 keV band is 61.9 +/- 3.2 ph/s/cm^2. The location, duration and spectrum of the source indicate that this is a burst from a source in the galactic center region, typical of a magnetar burst. We suggest that this is a burst from SGR 1806-20, but the location uncertainty is too large to draw any firm conclusions on its nature. The temporal and spectral analysis results presented above are preliminary."