TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2557 SUBJECT: GRB 040329: hard burst detected by Konus-Wind and Helicon - Coronas-F DATE: 04/03/31 13:50:06 GMT FROM: Dmitry Frederiks at Ioffe Institute S. Golenetskii, E. Mazets, V. Pal'shin, and D. Frederiks on behalf of Konus-Wind and Helicon/Coronas-F teams, T. Cline, on behalf of the Konus GRB team, A hard GRB 040329 was detected by Konus-Wind at 11:10:50.060 UT and Helicon-Coronas-F at 11:10:51.757 UT. It had a duration of approximately 2.3s, fluence 4.6x10-5 erg/cm2, and peak flux 1.2x10-4 erg/(cm2 s), both in 20-8000 keV range. Preliminary spectral analysis gives a value of Ep = 1900 +/- 100 keV. We have triangulated it to a preliminary annulus centered at RA(2000) = 114.620 deg, Decl(2000) = 22.903 deg, Radius = 59.12 +/- 0.16 degrees (3 sigma ). In addition, the Konus ecliptic latitude response limits the arrival directions to an ecliptic latitude of -30 +/- 7 degrees.