A Massive, Clumpy Molecular Gas Distribution and Displaced AGN in Zw 3146

TL;DR

This study uses ALMA and Chandra observations to analyze the molecular gas distribution and displaced AGN in Zw 3146, revealing complex gas filaments, potential gas condensation processes, and a displaced nucleus possibly due to a merger or gravitational wave recoil.

Contribution

First detailed ALMA and X-ray analysis of molecular gas and AGN displacement in Zw 3146, highlighting filamentary structures and potential merger signatures.

Findings

Molecular gas confined within 4 kpc, marginally resolved into filaments.

Molecular extensions trail X-ray cavities, indicating gas uplift from bubbles.

Displacement of the continuum source suggests a possible merging galaxy or recoil event.

Abstract

We present a recent ALMA observation of the CO(1-0) line emission in the central galaxy of the Zw 3146 galaxy cluster ($z=0.2906$). We also present updated X-ray cavity measurements from archival Chandra observations. The $5\times 10^{10}\,M_{\odot}$ supply of molecular gas, which is confined to the central 4 kpc, is marginally resolved into three extensions that are reminiscent of the filaments observed in similar systems. No velocity structure that would be indicative of ordered motion is observed. The three molecular extensions all trail X-ray cavities, and are potentially formed from the condensation of intracluster gas lifted in the wakes of the rising bubbles. Many cycles of feedback would be require to account for the entire molecular gas reservoir. The molecular gas and continuum source are mutually offset by 2.6 kpc, with no detected line emission coincident with the continuum source. It is the molecular gas, not the continuum source, that lies at the gravitational center of the brightest cluster galaxy. As the brightest cluster galaxy contains possible tidal features, the displaced continuum source may correspond to the nucleus of a merging galaxy. We also discuss the possibility that a gravitational wave recoil following a black hole merger may account for the displacement.