New Journal of Physics (Jan 2014)

The dynamic age of Centaurus A

  • Jean A Eilek

DOI
https://doi.org/10.1088/1367-2630/16/4/045001
Journal volume & issue
Vol. 16, no. 4
p. 045001

Abstract

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In this paper I present dynamic models of the radio source Centaurus A, and critique possible models of in situ particle reacceleration (ISR) within the radio lobes. The radio and γ -ray data require neither homogeneous plasma nor quasi-equipartition between the plasma and magnetic field; inhomogeneous models containing both high-field and low-field regions are equally likely. Cen A cannot be as young as the radiative lifetimes of its relativistic electrons, which range from a few to several tens of Myr. Two classes of dynamic models—flow driven and magnetically driven—are consistent with current observations; each requires Cen A to be on the order of a Gyr old. Thus, ongoing ISR must be occuring within the radio source. Alfven-wave ISR is probably occuring throughout the source, and may be responsible for maintaining the γ -ray-loud electrons. This is likely to be supplemented by shock or reconnection ISR, which maintains the radio-loud electrons in high-field regions.

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