//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9019 SUBJECT: GRB 090319: Fermi GBM detection DATE: 09/03/23 15:35:25 GMT FROM: Vandiver Chaplin at UAH/Fermi-GBM V.Chaplin (UAH) reports on behalf of the Fermi GBM Team: "At 14:55:35.22 UT on 19 MARCH 2009, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 090319 (trigger 259167337 / 090319622). The on-ground calculated location, using the GBM trigger data, is RA = 274.6, DEC = -11.4 (J2000 degrees, equivalent to 18h 18m, -11d 24'), with an uncertainty of 3.0 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 27 degrees. The GBM light curve consists of two ~6 s peaks at about T0+13 and T0+30 s on top of a smooth component, with a duration (T90) of about 67.7 s (8-1000 keV). The time-averaged spectrum from T0-6.144 to T0+37.889 s is best fit by a power law function with an exponential high energy cutoff. The power law index is 0.90 +/- 0.10 and the cutoff energy, parameterized as Epeak, is 187.3 +/- 20.4 keV (chi squared 463.25 for 467 d.o.f.). The event fluence (8-1000 keV) in this time interval is (7.47 +/- .53)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0+13.312 s in the 8-1000 keV band is 3.85 +/- 0.12 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."