# Radiative heating in the kinetic mode of AGN feedback

## TL;DR

This paper investigates radiative heating in the kinetic mode of AGN feedback, focusing on low-luminosity AGNs, and calculates the Compton temperature to improve understanding of AGN-host galaxy co-evolution.

## Contribution

It provides the first detailed calculation of Compton temperature for LLAGNs, highlighting the significance of radiative heating in the kinetic feedback mode.

## Key findings

- Compton temperature for LLAGNs is approximately (5-15)×10^7 K.
- Radiative heating in LLAGNs can surpass jet power over a wide parameter range.
- The spectral energy distribution of LLAGNs enhances radiative heating efficiency.

## Abstract

AGN feedback is now widely believed to play a crucial role in the co-evolution between the central black hole and its host galaxy. Two feedback modes have been identified, namely the radiative and kinetic modes, which correspond to the luminous AGNs and low-luminosity AGNs (LLAGNs), respectively. In this paper, we investigate the radiative heating in the kinetic mode. This process is potentially important because: 1) the radiation power of LLAGNs is higher than the jet power over a wide parameter range, 2) the spectral energy distribution of LLAGNs is such that the radiative heating is more effective compared to that of luminous AGNs with the same luminosity, and 3) most of the time in the lifecycle of an AGN is spent in the LLAGNs phase. In this paper, adopting the characteristic broad-band spectral energy distributions of LLAGNs, we calculate the value of "Compton temperature" ($T_{\rm c}$), which determines the radiative heating by Compton scattering. We find that $T_{\rm c}\sim (5-15)\times 10^7$ K, depending on the spectrum of individual LLAGN and at which distance from the black hole we evaluate the heating. We also compare this heating process with other radiative heating and cooling processes such as photoionization/recombination. Our result can be used for an accurate calculation of the radiative heating in the study of AGN feedback.