New constraints on the structure and dynamics of black hole jets

TL;DR

This study introduces a novel model to analyze multi-frequency observations of blazar jets, constraining their acceleration zones and revealing correlations between jet power, size, and Lorentz factors, advancing understanding of jet physics.

Contribution

The paper presents an innovative steady-state fluid flow model applied to 42 blazar spectra, providing new constraints on jet acceleration regions and their relation to jet power and structure.

Findings

Linear relation between jet power and brightest region radius

Correlation between acceleration length and Lorentz factor

Evidence for bimodal accretion rate distribution

Abstract

Accreting black holes produce powerful relativistic plasma jets which emit radiation across all observable wavelengths but the details of the initial acceleration and confinement of the jet are uncertain. We apply an innovative new model that allows us to determine key properties of the acceleration zone via multi-frequency observations. The central component of the model is a relativistic steady-state fluid flow, and the emission from physically distinct regions can be seen to contribute to different energy bands in the overall spectrum. By fitting with unprecedented accuracy to 42 simultaneous multiwavelength blazar spectra we are able to constrain the location of the brightest synchrotron emitting region, and show that there must be a linear relation between the jet power and the radius of the brightest region of the jet. We also find a correlation between the length of the accelerating region and the maximum bulk Lorentz factor of the jet and find evidence for a bimodal distribution of accretion rates in the blazar population. This allows us to put constraints on the basic dynamical and structural properties of blazar jets and to understand the underlying physical differences which result in the blazar sequence.