Direct Evidence for Outflow of Metal-enriched Gas Along the Radio Jets of Hydra A

TL;DR

Deep Chandra observations of Hydra A reveal that powerful radio jets transport metal-enriched gas from the galaxy center to larger radii, indicating active redistribution of metals by AGN activity.

Contribution

First direct evidence showing radio jets can uplift and spread metal-rich gas in galaxy clusters, quantifying the amount and energy involved.

Findings

Metallicity is enhanced along radio jets and lobes by up to 0.2 dex.

Approximately 10-20% of the central galaxy's iron mass is transported outward.

The energy to lift the gas is about 1-5% of the AGN's total output.

Abstract

Using deep Chandra observations of the Hydra A galaxy cluster, we examine the metallicity structure near the central galaxy and along its powerful radio source. We show that the metallicity of the intracluster medium is enhanced by up to 0.2 dex along the radio jets and lobes compared to the metallicity of the undisturbed gas. The enhancements extend from a radius of 20 kpc from the central galaxy to a distance of ~ 120 kpc. We estimate the total iron mass that has been transported out of the central galaxy to be between 2 x 10^7 M_sun and 7 x 10^7 M_sun which represents 10% - 20% of the iron mass within the central galaxy. The energy required to lift this gas is roughly 1% to 5% of the total energetic output of the AGN. Evidently, Hydra A's powerful radio source is able to redistribute metal-enriched, low entropy gas throughout the core of the galaxy cluster. The short re-enrichment time scale < 10^9 yr implies that the metals lost from the central galaxy will be quickly replenished.