TITLE: GCN CIRCULAR NUMBER: 11771 SUBJECT: GRB 110301A: Fermi GBM detection DATE: 11/03/03 08:56:47 GMT FROM: Suzanne Foley at MPE S. Foley (MPE) reports on behalf of the Fermi GBM Team: "At 05:08:43.07 UT on 01 March 2011, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 110301A (trigger 320648925 / 110301214). The on-ground calculated location, using the GBM trigger data, is RA = 229.35, DEC = 29.40 (J2000 degrees, equivalent to 15 h 17 m 24 s, 29 d 24 ' 00"), with an uncertainty of 1.0 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 94 degrees. GBM triggered an automatic repoint request to the Fermi Observatory to execute a maneuver following this trigger and track the burst location for the next 5 hours. However due to Earth-avoidance constraints, the slew did not commence until ~40 minutes after the trigger. The GBM light curve consists of a structured single pulse with a duration (T90) of about 5 s (50-300 keV). The time-averaged spectrum from T0+0.002 s to T0+5.824 s is best fit by a Band function with Epeak = 106.80 (+1.85/-1.75) keV, alpha = -0.81 (+/-0.02), and beta = -2.70 (+0.04/-0.05). The event fluence (10-1000 keV) in this time interval is (3.65 +/- 0.03)E-05 erg/cm^2. The 64-ms peak photon flux measured starting from T0+3.97 s in the 10-1000 keV band is 125.73 +/- 3.47 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."