Unveiling Chemical Enrichment in the Abell 2029 Core with XRISM, XMM-Newton, and Chandra

TL;DR

This study measures the chemical abundance pattern in the core of galaxy cluster Abell 2029 using multiple X-ray observatories, revealing insights into supernova contributions and elemental distributions.

Contribution

It provides the first comprehensive multi-instrument analysis of elemental abundances in A2029's core, highlighting a unique calcium excess and constraining supernova models.

Findings

Consistent Fe abundances across XRISM and XMM-Newton; RGS shows lower values.

Elemental abundance ratios suggest a mix of supernova types, favoring low-metallicity core-collapse and specific Type Ia models.

Detected calcium excess in the core not explained by standard supernova yields.

Abstract

We present new measurements of the chemical abundance pattern in the core of the nearby galaxy cluster Abell~2029, based on XRISM observations with Resolve (37 ks) and Xtend (500 ks), combined with archival data from XMM-Newton (EPIC, RGS) and Chandra. Fe abundances derived from Resolve, Xtend, and EPIC are broadly consistent, while RGS gives systematically lower values. Because the XRISM gate valve remained closed during these observations, Resolve spectral fitting is restricted to the 2--10 keV band, providing reliable constraints only for elements with strong lines in this band (S, Ar, Ca, Fe, Ni). Abundances of the $\alpha$-elements are therefore derived using complementary observations from Xtend, EPIC, RGS, and Chandra. We construct an average X/Fe pattern in the cluster core by using Resolve exclusively for S/Fe, Ar/Fe, Ca/Fe, and Ni/Fe, and RGS + Xtend for O/Fe. The Ne/Fe ratio is averaged from Xtend, EPIC, RGS, and Chandra measurements; Mg/Fe from EPIC and Chandra measurements; and Si/Fe from Xtend, EPIC, and Chandra. Comparison with the supernovae yield models indicates that the observed abundance pattern in A2029 core is best reproduced by a combination of core-collapsed yields from low-metallicity progenitors ($Z_{\rm init}=0.001$) and a sub-Chandrasekhar-mass, double-degenerate Type Ia model. Additionally, we find an excess in Ca abundance in the core of A2029 that cannot be reproduced by the standard supernovae yield models.