TITLE: GCN CIRCULAR NUMBER: 11878 SUBJECT: GRB 110401A: Fermi GBM detection DATE: 11/04/04 16:33:52 GMT FROM: Narayana Bhat at U Alabama/Huntsville/GBM P. N. Bhat (UAH) reports on behalf of the Fermi GBM Team: "Fermi Gamma-Ray Burst Monitor trigger at 22:04:19.63 UT on 01 April 2011, tentatively classified as "Below Horizon" by the flight software, is in fact due to GRB 110401A (trigger 323388261 / 110401920). The on-ground calculated location, using the GBM trigger data, is RA = 268.56, DEC = 26.87 (J2000 degrees, equivalent to 17 h 54 m, 26 d 52'), with an uncertainty of 3.8 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. The GBM light curve shows 2 strong pulses with a duration (T90) of about 2 s (50-300 keV). The time-averaged spectrum from T0-0.32 s to T0+0.704 s is well fit by a Band function with Epeak = 1194 +/- 406 keV, alpha = -0.66 +/- 0.15, and beta = -2.36 +/- 0.53 The event fluence (10-1000 keV) in this time interval is (1.51 +/- 0.09)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0-0.256 s in the 10-1000 keV band is 3.53 +/- 0.25 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."