Uniform Contribution of Supernova Explosions to the Chemical Enrichment of Abell 3112 out to R200

TL;DR

This study shows that supernova explosions contribute uniformly to the chemical enrichment of the galaxy cluster Abell 3112 out to its virial radius, indicating early enrichment before cluster formation.

Contribution

It provides the first detailed measurement of the uniform supernova type Ia contribution across the entire extent of a galaxy cluster, extending to its virial radius.

Findings

The supernova type Ia fraction is 12-16% out to the virial radius.

The supernova enrichment pattern is consistent with that of the Milky Way.

2D delayed detonation models fit the data worse than 1D models.

Abstract

The spatial distribution of the metals residing in the intra-cluster medium (ICM) of galaxy clusters records all the information on a cluster's nucleosynthesis and chemical enrichment history. We present measurements from a total of 1.2 Ms Suzaku XIS and 72 ks Chandra observations of the cool-core galaxy cluster Abell 3112 out its virial radius (~ 1470 kpc). We find that the ratio of the observed supernova type Ia explosions to the total supernova explosions has a uniform distribution at a level of 12-16% out to the cluster's virial radius. The observed fraction of type Ia supernova explosions is in agreement with the corresponding fraction found in our Galaxy and the chemical enrichment of our Galaxy. The non-varying supernova enrichment suggests that the ICM in cluster outskirts was enriched by metals at an early stage before the cluster itself was formed during the period of intense star formation activity. Additionally, we find that the 2D delayed detonation model CDDT produces significantly worse fits to the X-ray spectra compared to simple 1D W7 models. This is due to the relative overestimate of Si, and underestimate of Mg, in these models with respect to the measured abundances.