Constraining the origin and models of chemical enrichment in galaxy clusters using theAthenaX-IFU

Abstract

Chemical enrichment of the Universe at all scales is related to stellar winds and explosive supernovae phenomena. Metals produced by stars and later spread throughout the intracluster medium (ICM) at the megaparsec scale become a fossil record of the chemical enrichment of the Universe and of the dynamical and feedback mechanisms determining their circulation. As demonstrated by the results of the soft X-ray spectrometer onboard Hitomi, high-resolution X-ray spectroscopy is the path to differentiating among the models that consider different metal-production mechanisms, predict the outcoming yields, and are a function of the nature, mass, and/or initial metallicity of their stellar progenitor. Transformational results shall be achieved through improvements in the energy resolution and effective area of X-ray observatories, allowing them to detect rarer metals (e.g. Na, Al) and constrain yet-uncertain abundances (e.g. C, Ne, Ca, Ni). The X-ray Integral Field Unit (X-IFU) instrument onboard the next-generation European X-ray observatory Athena is expected to deliver such breakthroughs. Starting from 100 ks of synthetic observations of 12 abundance ratios in the ICM of four simulated clusters, we demonstrate that the X-IFU will be capable of recovering the input chemical enrichment models at both low (z = 0.1) and high (z = 1) redshifts, while statistically excluding more than 99.5% of all the other tested combinations of models. By fixing the enrichment models which provide the best fit to the simulated data, we also show that the X-IFU will constrain the slope of the stellar initial mass function within ∼12%. These constraints will be key ingredients in our understanding of the chemical enrichment of the Universe and its evolution.

The Metal Content of the Hot Atmospheres of Galaxy Groups

“…In the IGrM, the inferred 3D sonic Mach number of turbulence is Ma t ∼ 0.3-0.5 [254,255], i.e., σ v of a few 100 km s −1 . This can complement upcoming spectral X-ray IFU studies carried out via XRISM and Athena (see Section 4), with detailed synthetic observations already highlighting unprecedented features of metals and turbulence in hot halos [256][257][258][259]. Moreover, constraining the turbulent metal evolution in the IGrM plasma phase enables to assess the kinematics of the top-down multiphase rain, since the condensed warm (Hα+[NII]) filaments and cold (CO, HI) clouds share analogous ensemble velocity dispersion [260][261][262][263].…”

“…While the WFI is expected to discover a large number of high-redshift clusters and groups, the X-IFU will be able to investigate them spectroscopically with unprecedented resolving power. The promises of the latter have been thoroughly demonstrated in the case of clusters, in terms of spatial distribution of metals (Reference [257]; also see Section 3.2.1) but also of chemical composition and underlying stellar sources [259].…”

“…By giving us access to even more metals with even fainter lines than XRISM, the X-IFU will offer the best diagnostics of the SN explosion mechanisms, initial metallicity of the progenitor stars contributing to the enrichment of the cosmos, and especially the slope of the IMF, with the aim to contribute in a significant way to the debate about its universality. Higher line emissivities of a few key elements (e.g., O, Mg) at the groups regime are critical for constraining the IMF and will nicely complement the case of clusters, which will be thoroughly studied, as well (see, e.g., Reference [259]).…”

The warm-hot circumgalactic medium around EAGLE-simulation galaxies and its detection prospects with X-ray and UV line absorption

“…Many predictions of X-ray emission from hot haloes from numerical simulations have focussed on groups and clusters (e.g., Barnes et al 2017;Truong et al 2018;Cucchetti et al 2018;Mernier et al 2020), where much of the data is currently available and high photon counts will allow detailed information to be extracted. For EAGLE, Schaye et al (2015) have studied X-ray emission from groups and clusters, and Davies et al (2019) considered broad-band soft X-ray emission over a large range of halo masses and found it to be a good diagnostic of the CGM gas mass at fixed halo mass.…”

The metal content of the hot atmospheres of galaxy groups

“…In the IGrM, the inferred 3D sonic Mach number of turbulence is Ma t ∼ 0.3 − 0.5 (Hofmann et al, 2016;Ogorzalek et al, 2017), i.e., σ v of a few 100 km s −1 . This can complement upcoming spectral X-ray IFU studies carried out via XRISM and Athena (see §4), with detailed synthetic observations already highlighting unprecedented features of metals and turbulence in hot halos (Lau et al, 2017;Cucchetti et al, 2018;Roncarelli et al, 2018;Mernier et al, 2020a). Moreover, constraining the turbulent metal evolution in the IGrM plasma phase enables to assess the kinematics of the top-down multiphase rain, since the condensed warm (Hα+[NII]) filaments and cold (CO, HI) clouds share analogous ensemble velocity dispersion (Gaspari et al, 2018;Tremblay et al, 2018;Rose et al, 2019;Simionescu et al, 2019b).…”