A detailed kinematic study of 3C 84 and its connection to Gamma-rays

TL;DR

This study provides a detailed analysis of the jet kinematics in 3C 84, linking slow-moving jet features to gamma-ray emission and supporting models involving magnetic reconnection and turbulence.

Contribution

It offers the first detailed kinematic analysis of 3C 84's jet and its connection to gamma-ray flares, highlighting multiple high-energy sites and jet acceleration.

Findings

Jet accelerates to maximum speed within 125,000 gravitational radii.

Fastest jet speed detected is ~0.9 c, with a Lorentz factor of ~1.35.

Gamma-ray flares coincide with jet sub-region splitting events.

Abstract

3C 84 (NGC 1275) is the bright radio core of the Perseus Cluster. Even in the absence of strong relativistic effects, the source has been detected at Gamma-rays up to TeV energies. Despite its intensive study, the physical processes responsible for the high-energy emission in the source remain unanswered. We present a detailed kinematics study of the source and its connection to Gamma-ray emission. The sub-parsec scale radio structure is dominated by slow-moving features in both the eastern and western lanes of the jet. The jet appears to have accelerated to its maximum speed within less than 125 000 gravitational radii. The fastest reliably detected speed in the jet was ~0.9 c. This leads to a minimum Lorentz factor of ~1.35. Our analysis suggests the presence of multiple high-energy sites in the source. If Gamma-rays are associated with kinematic changes in the jet, they are being produced in both eastern and western lanes in the jet. Three Gamma-ray flares are contemporaneous with epochs where the slowly moving emission region splits into two sub-regions. We estimate the significance of these events being associated as ~2-3 sigma. We tested our results against theoretical predictions for magnetic reconnection-induced mini-jets and turbulence and find them compatible.