A census of cool-core galaxy clusters in IllustrisTNG

  • David J. Barnes
  • , Mark Vogelsberger
  • , Rahul Kannan
  • , Federico Marinacci
  • , Rainer Weinberger
  • , Volker Springel
  • , Paul Torrey
  • , Annalisa Pillepich
  • , Dylan Nelson
  • , Rüdiger Pakmor
  • , Jill Naiman
  • , Lars Hernquist
  • , Michael McDonald

Research output: Contribution to journalArticlepeer-review

Abstract

The thermodynamic structure of hot gas in galaxy clusters is sensitive to astrophysical processes and typically difficult to model with galaxy formation simulations. We explore the fraction of cool-core (CC) clusters in a large sample of 370 clusters from IllustrisTNG, examining six common CC definitions. IllustrisTNG produces continuous CC criteria distributions, the extremes of which are classified as CC and non-cool core (NCC), and the criteria are increasingly correlated for more massive clusters. At z = 0, the CC fractions for two criteria are in reasonable agreement with the observed fractions but the other four CC fractions are lower than observed. This result is partly driven by systematic differences between the simulated and observed gas fraction profiles. The simulated CC fractions with redshift show tentative agreement with the observed fractions, but linear fits demonstrate that the simulated evolution is steeper than observed. The conversion of CCs to NCCs appears to begin later and act more rapidly in the simulations. Examining the fraction of CCs and NCCs defined as relaxed we find no evidence that CCs are more relaxed, suggesting that mergers are not solely responsible for disrupting CCs. A comparison of the median thermodynamic profiles defined by different CC criteria shows that the extent to which they evolve in the cluster core is dependent on the CC criteria. We conclude that the thermodynamic structure of galaxy clusters in IllustrisTNG shares many similaritieswith observations, but achieving better agreement most likely requires modifications of the underlying galaxy formation model.

Original languageEnglish (US)
Pages (from-to)1809-1831
Number of pages23
JournalMonthly Notices of the Royal Astronomical Society
Volume481
Issue number2
Early online dateAug 3 2018
DOIs
StatePublished - Dec 1 2018
Externally publishedYes

Keywords

  • Galaxies: clusters: general
  • Galaxies: clusters: intracluster medium
  • Methods: numerical
  • X-rays: galaxies: clusters

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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