TITLE: GCN CIRCULAR NUMBER: 6135 SUBJECT: RHESSI Spectrum of GRB070220 DATE: 07/02/23 18:32:12 GMT FROM: Eric Bellm at UCB/SSL C. Wigger, E. Bellm, M. Bandstra, S. Boggs, W. Hajdas, D. M. Smith, and K. Hurley on behalf of the RHESSI team report: As observed by RHESSI, GRB070220 (M. Stamatikos et al., GCN 6114) had a duration of ~30s starting at about T0=04:44:33 UT. A fit to the time-integrated RHESSI spectrum of the main period of emission from T0 - T0+18s between 30 keV and 3.0 MeV gives a cutoff power law, with alpha = -0.65 +0.40/-0.35 E0 = 235 +180/-90 keV Epeak = 315 +115/-70 keV (90% confidence levels). The 20 keV-2 MeV fluence is (1.14 +0.16/-0.12) E-5 erg/cm^2.