Metals in the Intracluster Medium of MS 1512.4+3647 Observed with Suzaku: Implications for the Metal Enrichment History

TL;DR

This study analyzes the metal abundances in the galaxy cluster MS 1512.4+3647 using Suzaku data, revealing that its enrichment history and supernova contributions are similar to those of nearby clusters, supporting standard cosmic evolution models.

Contribution

First measurement of Mg, Si, S, and Ni abundances in a medium redshift cluster, showing consistent enrichment patterns with nearby clusters and providing insights into supernova contributions over cosmic time.

Findings

Abundance pattern matches nearby clusters, indicating similar supernova contributions.

SN II to SN Ia ratio is approximately 3.

SN Ia rate declines steeply from z=0.37 to 0.

Abstract

The cluster of galaxies MS 1512.4+3647 (z=0.372) was observed with Suzaku for 270 ks. Besides the Fe abundance, the abundances of Mg, Si, S, and Ni are separately determined for the first time in a medium redshift cluster (z>0.3). The derived abundance pattern of MS 1512.4+3647 is consistent with those of nearby clusters, suggesting that the system has similar contributions from supernovae (SNe) Ia and SNe II to nearby clusters. The number ratio of SNe II to SNe Ia is $\sim3$. The estimated total numbers of both SNe II and SNe Ia against gas mass indicate similar correlation with those for the nearby clusters. The abundance results of MS 1512.4+3647 is consistent with the standard scenario that the SN II rate history roughly follows the star-formation history which has a peak at 1<z<2 and then declines by about one order of magnitude toward $z\sim0$. The similar number of SNe Ia to the nearby clusters suggests that the SN Ia rate declines steeply from z=0.37 to z=0 and/or SN Ia explosions occurred predominantly at larger redshifts.