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

¹ European Space Agency (ESA), European Space Research and Technology Centre (ESTEC), Keplerlaan 1, 2201 AZ Noordwijk, The Netherlands
e-mail: francois.mernier@esa.int
² MTA-Eötvös University Lendület Hot Universe Research Group, Pázmány Péter sétány 1/A, Budapest 1117, Hungary
³ Institute of Physics, Eötvös University, Pázmány Péter sétány 1/A, Budapest 1117, Hungary
⁴ SRON Netherlands Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht, The Netherlands
⁵ IRAP, Université de Toulouse, CNRS, CNES, UPS, Toulouse, France
⁶ INAF, Osservatorio Astronomico di Trieste, Via Tiepolo 11, 34131 Trieste, Italy
⁷ Universitäts-Sternwarte München, Fakultät für Physik, LMU Munich, Scheinerstr. 1, 81679 München, Germany
⁸ IFPU – Institute for Fundamental Physics of the Universe, Via Beirut 2, 34014 Trieste, Italy
⁹ CNES, 18 Avenue Edouard, Belin, 31400 Toulouse, France
¹⁰ Dipartimento di Fisica dell’Universitä di Trieste, Sezione di Astronomia, via Tiepolo 11, 34131 Trieste, Italy
¹¹ INFN – National Institute for Nuclear Physics, Via Valerio 2, 34127 Trieste, Italy
¹² Max-Planck-Institut für extraterrestrische Physik, Gießenbachstraße 1, 85748 Garching, Germany
¹³ Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA
¹⁴ Dr. Karl Remeis-Observatory, Erlangen Centre for Astroparticle Physics, Sternwartstr. 7, 96049 Bamberg, Germany
¹⁵ University Observatory Munich, Scheinerstr. 1, 81679 Munich, Germany
¹⁶ Max Plank Institut für Astrophysik, Karl-Schwarzschield Strasse 1, 85748 Garching bei Munchen, Germany
¹⁷ INAF, Osservatorio di Astrofisica e Scienza dello Spazio, via Piero Gobetti 93/3, 40129 Bologna, Italy
¹⁸ INFN, Sezione di Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy
¹⁹ Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544, USA
²⁰ Dipartimento di Fisica e Astronomia, Universitá di Bologna, Via Gobetti 93, 40127 Bologna, Italy

Received: 11 June 2020
Accepted: 30 July 2020

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.