GCN Circular 10355
A. von Kienlin (MPE), P. N. Bhat (UAH) and R. D. Preece (UAH) report on behalf of the Fermi GBM Team: "At 14:47:37.31 UT on 22 January 2010, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 100122A (trigger 285864459 / 100122616). The on-ground calculated location, using the GBM trigger data, is RA = 79.2 , DEC = -2.7 (J2000 degrees, equivalent to 05h 16.8m, -2d 42'), with an uncertainty of 1.3 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 45 degrees. This burst was also independently detected by INTEGRAL SPI-ACS. The GBM light curve consists of 2 pulses (a weak pulse at trigger followed by a much larger pulse about 21 s later) with a duration (T90) of about 6.6 s (8-1000 keV). The time-averaged spectrum from T0-2.688 s to T0+25.984 s is adequately fit by a Band function with Epeak = 45.6 +/- 1.5 keV, alpha = -0.98 +/- 0.05, and beta = -2.31 +/- 0.03 (CSTAT 1673 for 478 d.o.f.). The event fluence (8-1000 keV) in this time interval is (1.00 +/- 0.01)E-05 erg/cm^2. The 1.0-sec peak photon flux measured starting from T0+20.9 s in the 8-1000 keV band is 10.44 +/- 0.07 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."