1920018

Despite decades of observations the nature of the hard X-ray/soft gamma-ray emission of Cen A the brightestradio-loud AGN in the hard X-ray sky is still unclear. The two main competing models are thermal Comptonizationand synchrotron self-Compton emission and they predicted a spectral cutoff of roughly 300 keV or above 1 MeVrespectively and requires spectral coverage out to the MeV region to differentiate. INTEGRAL/SPI has spectral coverageto a few MeV and thus capability to constrain where the spectral cutoff occurs and assess the origin of the hardX-ray/soft gamma-ray emission. SPIs high energy resolution can also search for 511 keV annihilation features inthe spectrum on both short and long timescales. Motivated by this we request a multi-year normal time proposal of3 Ms of exposure time in AO-19 and 3 Ms on exposure time in AO-20. [truncated! Please see actual data for full text]