Title: Physical Conditions and Particle Acceleration in the Kiloparsec Jet of Centaurus A.
Authors: Takahiro Sudoh, Dmitry Khangulyan, Yoshiyuki Inoue
The non-thermal emission from the kiloparsec-scale jet of Centaurus~A exhibits two notable features, bright diffuse emission and many compact knots, which have been intensively studied in X-ray and radio observations. H.E.S.S. recently reported that the very-high-energy gamma-ray emission from this object is extended along the jet direction beyond a kiloparsec from the core. Here, we combine these observations to constrain the physical conditions of the kpc-jet and study the origin of the non-thermal emission. We show that the diffuse jet is weakly magnetized ($\eta_B\sim10^{-2}$) and energetically dominated by thermal particles. We also show that knots are the sites of both amplified magnetic field and particle (re-)acceleration. To keep sufficient energy in thermal particles, the magnetic and non-thermal particle energy in the knot regions are tightly constrained. The most plausible condition is an energy equipartition between them, $\eta_B\sim\eta_e\sim0.1$. Such weak magnetic energy implies that particles in the knots are in the slow cooling regime. We suggest that the entire kpc-scale diffuse emission could be powered by particles that are accelerated at and escaped from knots.
も参照してください
- Our paper on the coronal cosmic-ray energy budget in AGNs is accepted by PASJ.
- Our paper on cosmic rays in cosmological filaments is accepted by Universe.
- Our paper on multi-epoch X-ray spectral analysis of Cen A is accepted by PASJ.
- Our paper on radio emission from AGN disk winds is accepted by ApJ.
- Our paper on Millimeter Time Variability in the Gamma-Ray Detected Seyfert Galaxy GRS 1734-292 is accepted by ApJ.