Elemental abundances and chemical enrichment of the intra-cluster medium
Intervenant : François Mernier
SRON & Eötvös Loránd University
Whereas the extreme conditions of the first minutes after the Big Bang produced nearly all the hydrogen and helium in the Universe, the most common heavier elements - or metals - are synthesised in the core of stars and in supernova explosions. Currently, however, the behaviour of supernovae (and their stellar progenitors) is not well understood, and could be better constrained by measuring accurately the relative amount of metals they produce. On the other hand, the very hot and diffuse intra-cluster medium (ICM), glowing in X-ray and detected in the large gravitational potential well of galaxy clusters and groups, is also rich in metals. This means that the building blocks of life, synthesised by billions on supernovae over cosmic times, are present even at the largest scales of the Universe, as they continuously enrich the ICM.
In this seminar, I will review how the abundance measurements of key-elements in the hot atmosphere of galaxy clusters, groups, and ellipticals observed with the current X-ray observatories helps to know:
(i) what are the explosion mechanisms and the environmental conditions of Type Ia and core-collapse supernovae,
(ii) at which epoch of the cosmic history the ICM got enriched,
(iii) how metals get transported across the ICM.
Finally, I will discuss how the promising future X-ray observatory Athena (in which IRAP plays a central role) will push forward our understanding of the ICM enrichment.