A General Precipitation-Limited L_X-T-R Relation Among Early-Type Galaxies

TL;DR

This paper introduces a precipitation-regulated model for the L_X-T relation in early-type galaxies, successfully explaining observed trends across a wide temperature range and linking galaxy feedback mechanisms to cluster core regulation.

Contribution

It presents a unified precipitation-based model for the L_X-T relation that applies across different galaxy mass scales and matches observational data.

Findings

The model reproduces the slope and upper envelope of the L_X-T-R relation.

Feedback mechanisms in galaxies and clusters share common precipitation-triggered processes.

The relation holds from low-temperature galaxies to hot galaxy clusters.

Abstract

The relation between X-ray luminosity (L_X) and ambient gas temperature (T) among massive galactic systems is an important cornerstone of both observational cosmology and galaxy-evolution modeling. In the most massive galaxy clusters, the relation is determined primarily by cosmological structure formation. In less massive systems, it primarily reflects the feedback response to radiative cooling of circumgalactic gas. Here we present a simple but powerful model for the L_X-T relation as a function of physical aperture R within which those measurements are made. The model is based on the precipitation framework for AGN feedback and assumes that the circumgalactic medium is precipitation-regulated at small radii and limited by cosmological structure formation at large radii. We compare this model with many different data sets and show that it successfully reproduces the slope and upper envelope of the L_X-T-R relation over the temperature range from ~0.2 keV through >10 keV. Our findings strongly suggest that the feedback mechanisms responsible for regulating star formation in individual massive galaxies have much in common with the precipitation-triggered feedback that appears to regulate galaxy-cluster cores.