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Is the High-Energy Emission from Centaurus A Compton-Scattered Jet Radiation?

J. G. Skibo·C. D. Dermer·R. L. Kinzer
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Abstract

We consider whether the hard X-ray and soft gamma-ray emission from Centaurus A is beamed radiation from the active nucleus which is Compton-scattered into our line-of-sight. We derive the spectrum and degree of polarization of scattered radiation when incident beamed radiation is scattered from a cold ($kT<<m_ec^2$) electron cloud moving with bulk relativistic motion along the jet axis, and calculate results for an unpolarized, highly-beamed incident power-law photon source. We fit the OSSE data from Centaurus A with this model and find that if the scatterers are not moving relativistically, then the angle the jet makes with respect to our line-of-sight is $61^\circ\pm 5^\circ$. We predict a high degree of polarization of the scattered radiation below $\sim300$ keV. Future measurements with X-ray and gamma-ray polarimeters could be used to constrain or rule out such a scenario.

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J. G. Skibo, C. D. Dermer, R. L. Kinzer. 1994-02-18. Is the High-Energy Emission from Centaurus A Compton-Scattered Jet Radiation?. https://doi.org/10.1086/187330

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