On the X-ray low- and high-velocity outflows in AGNs

TL;DR

This paper investigates the relationship between luminosity and outflow velocity in X-ray outflows of AGNs, suggesting radiation pressure as a key acceleration mechanism and linking outflow properties to their galactic locations.

Contribution

It provides new insights into the physical mechanisms driving AGN outflows and their connection to the outflows' velocities and locations within the galaxy.

Findings

Line radiation pressure can accelerate warm absorber outflows.

Ultra-fast outflows are likely driven by similar mechanisms at smaller scales.

Outflow velocities correlate with the distance from the galactic center.

Abstract

An exploration of the relationship between bolometric luminosity and outflow velocity, for two classes of X-ray outflows in a large sample of active galactic nuclei has been performed. We find that line radiation pressure could be one physical mechanism that might accelerate the gas we observe in warm absorber, v~100-1000 km/s, and on comparable but less stringent grounds the ultra-fast outflows (UFOs), v~0.03-0.3c. If comparable with the escape velocity of the system; the first is naturally located at distances of the dusty torus, ~ 1 pc, and the second at sub-parsec scales, ~ 0.01 pc, in accordance with large set of observational evidence existing in the literature. The presentation of this relationship might give us key clues for our understanding of the different physical mechanisms acting in the center of galaxies, the feedback process and its impact on the evolution of the host galaxy.