Can AGN activity be enhanced by ram pressure stripping? -- X-ray perspective

TL;DR

This study investigates whether ram pressure stripping (RPS) enhances AGN activity in cluster galaxies from an X-ray perspective, finding no significant evidence of increased X-ray AGN activity due to RPS in their sample.

Contribution

First X-ray study to examine the connection between RPS and AGN activity in cluster galaxies, providing observational evidence that RPS does not significantly enhance X-ray AGN activity.

Findings

Most RPS galaxies have X-ray luminosities below 10^41 erg/s.

No significant difference in X-ray AGN activity between RPS and non-RPS galaxies.

The most luminous X-ray AGN was found in a RPS galaxy, but overall enhancement is not observed.

Abstract

Ram pressure stripping (RPS) is an important process that plays a significant role in shaping the evolution of cluster galaxies and their surrounding environment. Despite its recognized significance, the potential connection between RPS and AGN activity in cluster galaxies remains poorly understood. Recent claims, based on optical emission line diagnostics, have suggested such a connection. Here, we investigate this relationship from an X-ray perspective using a sample of galaxies undergoing RPS in four nearby galaxy clusters - A1656, A1367, A426, and A3627. This study is the first to test such a connection from an X-ray standpoint. Our analysis reveals no signs of enhanced X-ray AGN activity in our sample, with most RPS galaxies ($\sim$ $90\%$) showing X-ray luminosities below $10^{41}$ erg s$^{-1}$ in their central point sources. Moreover, there is no noticeable difference in X-ray AGN activity among RPS galaxies compared to a control sample of non-RPS galaxies, as demonstrated by similar X-ray luminosities observed in their central point sources. While the most luminous X-ray AGN in our sample is found in ESO 137-002, a galaxy undergoing RPS in A3627, there is no evidence for a widespread enhancement of X-ray AGN activity due to RPS. Given the limited sample size of our study, this could also indicate that either the X-ray AGN enhancement from RPS is at most weak, or the timescale for the X-ray AGN enhancement is short. This emphasizes the need for further investigations with larger X-ray samples to better understand the impact of RPS on AGN activity in cluster galaxies.