The X-ray cavities, filaments and cold fronts in the core of the galaxy group NGC 5044

TL;DR

This study analyzes X-ray features in galaxy group NGC 5044, revealing cavities, filaments, and cold fronts that suggest recent AGN activity and dynamical interactions affecting the group's core structure.

Contribution

It provides a detailed two-dimensional analysis of X-ray structures in NGC 5044, linking them to AGN outbursts and group dynamics, which is a novel comprehensive study of this galaxy group.

Findings

Detection of cavities and filaments indicating AGN activity

Identification of cold fronts suggesting sloshing due to accretion

Correlation of X-ray filaments with H_alpha and dust emission

Abstract

We present a two-dimensional analysis of the bright nearby galaxy group NGC 5044 using the currently available Chandra and XMM data. In the inner 10 kpc a pair of cavities are evident together with a set of bright X-ray filaments. If the cavities are interpreted as gas displaced by relativistic plasma inflated by an AGN, even in the absence of extended 1.4 GHz emission, this would be consistent with a recent outburst as also indicated by the extent of dust and H_alpha emission. The soft X-ray filaments coincident with H_alpha and dust emission are cooler than the ones which do not correlate with optical and infrared emission. We suggest that dust-aided cooling contributes to form warm (T =10^4 K) gas, emitting H_alpha radiation. At 31 kpc and 67 kpc a pair of cold fronts are present, indicative of sloshing due to a dynamical perturbation caused by accretion of a less massive group, also suggested by the peculiar velocity of the brightest galaxy NGC 5044 with respect to the mean group velocity.