Publication Date:
2020-06-05
Description:
We present results from a 577 ks XMM–Newton observation of SPT-CL J0459–4947, the most distant cluster detected in the South Pole Telescope 2500 square degree (SPT-SZ) survey, and currently the most distant cluster discovered through its Sunyaev–Zel’dovich effect. The data confirm the cluster’s high redshift, z = 1.71 ± 0.02, in agreement with earlier, less precise optical/IR photometric estimates. From the gas density profile, we estimate a characteristic mass of $M_{500}=(1.8pm 0.2)imes 10^{14}, {
m M}_{odot }$; cluster emission is detected above the background to a radius of $sim !2.2, r_{500}$, or approximately the virial radius. The intracluster gas is characterized by an emission-weighted average temperature of 7.2 ± 0.3 keV and metallicity with respect to Solar of $Z/, Z_{odot }=0.37pm 0.08$. For the first time at such high redshift, this deep data set provides a measurement of metallicity outside the cluster centre; at radii $rgt 0.3, r_{500}$, we find $Z/, Z_{odot }=0.33pm 0.17$ in good agreement with precise measurements at similar radii in the most nearby clusters, supporting an early enrichment scenario in which the bulk of the cluster gas is enriched to a universal metallicity prior to cluster formation, with little to no evolution thereafter. The leverage provided by the high redshift of this cluster tightens by a factor of 2 constraints on evolving metallicity models, when combined with previous measurements at lower redshifts.
Print ISSN:
0035-8711
Electronic ISSN:
1365-2966
Topics:
Physics
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