Pinpointing the base of the AGN jets through general relativistic X-ray reverberation studies

TL;DR

This study uses advanced general relativistic X-ray reverberation modeling of 12 AGN to precisely locate the jet base and understand the black hole environment, providing insights into jet launching mechanisms.

Contribution

First systematic application of GR ray tracing to model X-ray time-lags in multiple AGN, pinpointing the jet base location within the black hole environment.

Findings

Identified the position of the AGN jet-base in each source.

Demonstrated the effectiveness of GR response models combined with innovative fitting routines.

Provided constraints on black hole properties such as mass and spin.

Abstract

Many theoretical models of Active Galactic Nuclei (AGN) predict that the X-ray corona, lying above the black hole, constitutes the base of the X-ray jet. Thus, by studying the exact geometry of the close black hole environment, we can pinpoint the launching site of the jet. Detection of negative X-ray reverberation time delays (i.e. soft band X-ray variations lagging behind the corresponding hard band X-ray variations) can yield significant information about the geometrical properties of the AGN, such as the location of the X-ray source, as well as the physical properties of the the black hole, such as its mass and spin. In the frame-work of the lamp-post geometry, I present the first systematic X-ray time-lag modelling results of an ensemble of 12 AGN, using a fully general relativistic (GR) ray tracing approach for the estimation of the systems' response functions. By combing these state-of-the art GR response models with statistically innovative fitting routines, I derive the geometrical layout of the close BH environment for each source, unveiling the position of the AGN jet-base.