TITLE: GCN CIRCULAR NUMBER: 6399 SUBJECT: RHESSI Spectrum of GRB070508 DATE: 07/05/09 19:35:36 GMT FROM: Eric Bellm at UCB/SSL E. Bellm, C. Wigger, M. Bandstra, S. Boggs, W. Hajdas, D. M. Smith, and K. Hurley on behalf of the RHESSI team report: As observed by RHESSI, GRB070508 (Grupe et al., GCN 6383) had a duration of ~18 s starting at about T0=04:18:20 UT. RHESSI detected significant emission up to ~300 keV. The preliminary fit to the time-integrated RHESSI spectrum from T0 - T0+16 s between 30 keV and 10 MeV is a cutoff power law with alpha = -0.76 +0.52/-0.41 Epeak = 254 +71/-45 keV (90% confidence levels). The 30 keV-10 MeV fluence is 1.95 +0.28/-0.23 E-5 erg/cm^2.