Advection of Accelerated Electrons in Radio/X-ray Knots of AGN Jets

TL;DR

This paper presents a model explaining the X-ray emission in AGN jet knots through synchrotron radiation from both accelerated and advected electrons, aligning with observations and gamma-ray constraints.

Contribution

It introduces a novel model considering advected electron populations to explain multi-wavelength emissions in AGN jets, addressing previous inverse Compton limitations.

Findings

Successfully reproduces radio to X-ray fluxes of 3C 273 knots.

Inverse Compton emission remains within Fermi gamma-ray limits.

Highlights the importance of advected electrons in jet emission models.

Abstract

The X-ray emission from the knots of the kilo-parsec scale jet of active galactic nuclei (AGN) suggests the high energy emission process is different from the radio/optical counterpart. Interpretation based on the Inverse Compton scattering of cosmic microwave photons has been ruled out through Fermi gamma-ray observations for low redshift sources. As an alternate explanation, synchrotron emission from a different electron population is suggested. We propose a model considering the advected electron distribution from the sites of particle acceleration in AGN knots. This advected electron distribution is significantly different from the accelerated electron distribution and satisfies the requirement of the second electron population. The synchrotron emission from the accelerated and the advected electron distribution can successfully reproduce the observed radio to X-ray fluxes of the knots of 3C 273. For the chosen combination of the model parameters, the spectrum due to inverse Compton scattering of cosmic microwave photons falls within the Fermi gamma-ray upper limits.