Molecular accretion in the core of the galaxy cluster 2A 0335+096

TL;DR

This study uses advanced spectroscopy to analyze molecular gas accretion in the galaxy cluster 2A 0335+096, revealing a rotating H2 structure linked to AGN activity and supporting cold feedback models for cluster heating.

Contribution

It provides detailed observations of molecular gas dynamics and accretion processes in a galaxy cluster core, highlighting the role of cold gas in AGN feedback.

Findings

H2 emission is concentrated in two peaks near the nucleus.

The H2 is in a rotating structure aligned with radio lobes.

The gas reservoir could fuel AGN activity for over 1 Gyr.

Abstract

We present adaptive optics-assisted K-band integral field spectroscopy of the central cluster galaxy in 2A 0335+096 (z=0.0349). The H2 v=1-0 S(1) emission is concentrated in two peaks within 600 pc of the nucleus and fainter but kinematically-active emission extends towards the nucleus. The H2 is in a rotating structure which aligns with, and appears to have been accreted from, a stream of H-alpha emission extending over 14 kpc towards a companion galaxy. The projected rotation axis aligns with the 5 GHz radio lobes. This H2 traces the known 1.2E9 Msun CO-emitting reservoir; limits on the Br-gamma emission confirm that the H2 emission is not excited by star formation, which occurs at a rate of less than 1 Msun/yr in this gas. If its accretion onto the black hole can be regulated whilst star formation remains suppressed, the reservoir could last for at least 1 Gyr; the simultaneous accretion of just ~ 5 per cent of the gas could drive a series of AGN outbursts which offset X-ray cooling in the cluster core for the full 1 Gyr. Alternatively, if the regulation is ineffective and the bulk of the H2 accretes within a few orbital periods (25-100 Myr), the resulting 1E62 erg outburst would be among the most powerful cluster AGN outbursts known. In either case, these observations further support cold feedback scenarios for AGN heating.