On the Fe abundance peak formation in cool-core clusters of galaxies: hints from cluster WARPJ1415.1+3612 at z=1.03

TL;DR

This study investigates the iron abundance peak in a high-redshift galaxy cluster, revealing that the core's iron content was largely established by z=1, indicating early star formation and minimal redistribution of iron compared to local clusters.

Contribution

It provides the first detailed measurement of iron content in a z=1.03 cool-core cluster, showing early formation of the Fe peak and comparing its distribution to local clusters.

Findings

Iron mass excess was already in place at z=1.

The Fe distribution in the cluster matches the BCG light profile.

Early and intense star formation likely formed the Fe peak.

Abstract

We present a detailed study of the iron content of the core of the high-redshift cluster WARPJ1415.1+3612 (z=1.03). By comparing the central Fe mass excess observed in this system, M_Fe^exc = (1.67 +/- 0.40) x 10^9 M_sun, with those measured in local cool-core systems, we infer that the bulk of the mass excess was already in place at z=1, when the age of the Universe was about half of what it is today. Our measures point to an early and intense period of star formation most likely associated with the formation of the BCG. Indeed, in the case of the power-law delay time distribution with slope -1, which reproduces the data of WARPJ1415.1+3612 best, half of the supernovae explode within 0.4 Gyr of the formation of the BCG. Finally, while for local cool-core clusters the Fe distribution is broader than the near infrared light distribution of the BCG, in WARPJ1415.1+3612 the two distributions are consistent, indicating that the process responsible for broadening the Fe distribution in local systems has not yet started in this distant cluster.