%0 Journal Article
%T First Results from Fermi GBM Earth Occultation Monitoring: Observations of Soft Gamma-Ray Sources Above 100 keV
%A Gary L. Case
%A Michael L. Cherry
%A James C. Rodi
%A Peter Jenke
%A Colleen A. Wilson-Hodge
%A Mark H. Finger
%A Charles A. Meegan
%A Ascencion Camero-Arranz
%A Elif Beklen
%A P. Narayan Bhat
%A Michael S. Briggs
%A Vandiver Chaplin
%A Valerie Connaughton
%A William S. Paciesas
%A Robert Preece
%A R. Marc Kippen
%A Andreas von Kienlin
%A Jochen Griener
%J Physics
%D 2010
%I arXiv
%R 10.1088/0004-637X/729/2/105
%X The NaI and BGO detectors on the Gamma-ray Burst Monitor (GBM) on Fermi are now being used for long-term monitoring of the hard X-ray/low energy gamma-ray sky. Using the Earth occultation technique as demonstrated previously by the BATSE instrument on the Compton Gamma-Ray Observatory, GBM can be used to produce multiband light curves and spectra for known sources and transient outbursts in the 8 keV to 1 MeV energy range with its NaI detectors and up to 40 MeV with its BGO detectors. Over 85% of the sky is viewed every orbit, and the precession of the Fermi orbit allows the entire sky to be viewed every ~26 days with sensitivity exceeding that of BATSE at energies below ~25 keV and above ~1.5 MeV. We briefly describe the technique and present preliminary results using the NaI detectors after the first two years of observations at energies above 100 keV. Eight sources are detected with a significance greater than 7 sigma: the Crab, Cyg X-1, SWIFT J1753.5-0127, 1E 1740-29, Cen A, GRS 1915+105, and the transient sources XTE J1752-223 and GX 339-4. Two of the sources, the Crab and Cyg X-1, have also been detected above 300 keV.
%U http://arxiv.org/abs/1009.4953v1