OSSE Observations of Diffuse Galactic Continuum Radiation
Session 29 -- Gamma Ray Astrophysics
Oral presentation, Wednesday, January 12, 2:15-3:45, Salon III Room (Crystal Gateway)

## [29.08] OSSE Observations of Diffuse Galactic Continuum Radiation

W.R.~Purcell, D.A.~Grabelsky, M.P.~Ulmer (Northwestern Univ.), J.G.~Skibo (NRL/NRC), W.N.~Johnson, R.L.~Kinzer, J.D.~Kurfess, M.S.~Strickman (NRL), G.~Jung (USRA)

\def\MeV{Me\kern-0.11em V}

The Oriented Scintillation Spectrometer Experiment (OSSE) onboard NASA's {\it Compton Gamma-Ray Observatory\/} is sensitive to gamma-ray line and continuum emission in the 0.05 -- 10 \MeV\ energy range. Collimation of the NaI(Tl) detectors provides a full-width at half-maximum field of view which is $3.8^\circ \times 11.4^\circ$. During the Phase 1 and Phase 2 mission operations, OSSE performed numerous observations of the Galactic plane and Galactic center region. In part, these observations were designed to allow the generation of maps of the diffuse Galactic gamma-ray emission.

The low energy diffuse Galactic gamma-ray continuum is thought to be produced primarily by bremsstrahlung and inverse Compton scattering of cosmic-ray electrons with the ambient interstellar matter and radiation. An understanding of the angular distribution and spectral characteristics of the emission will provide information about the morphology and energetics of the cosmic-ray electrons believed to be responsible for the continuum emission.

Analysis of the OSSE Galactic center and Galactic plane observations show low energy continuum emission along the Galactic plane to longitudes of $\sim \pm 60^\circ$. Preliminary results from an analysis of the OSSE data to measure the spectral characteristics and angular distribution of the diffuse emission will be presented.