The metal enrichment of passive galaxies in cosmological simulations of galaxy formation

• Okamoto, Takashi

• Nagashima, Masahiro

• Lacey, Cedric G.

• Frenk, Carlos S.

Abstract

Massive early-type galaxies have higher metallicities and higher ratios of a elements to iron than their less massive counterparts. Reproducing these correlations has long been a problem for hierarchical galaxy formation theory, both in semi-analytic models and cosmological hydrodynamic simulations. We show that a simulation in which gas cooling in massive dark haloes is quenched by radio-mode active galactic nuclei (AGNs) feedback naturally reproduces the observed trend between alpha/Fe and the velocity dispersion of galaxies, sigma. The quenching occurs earlier for more massive galaxies. Consequently, these galaxies complete their star formation before a/Fe is diluted by the contribution from Type Ia supernovae. For galaxies more massive than similar to 10(11)M(circle dot), whose alpha/Fe correlates positively with stellar mass, we find an inversely correlated mass-metallicity relation. This is a common problem in simulations in which star formation in massive galaxies is quenched either by quasar- or radio-mode AGN feedback. The early suppression of gas cooling in progenitors of massive galaxies prevents them from recapturing enriched gas ejected as winds. Simultaneously reproducing the [alpha/Fe]-sigma relation and the mass-metallicity relation is, thus, difficult in the current framework of galaxy formation.

Journal

• Monthly notices of the royal astronomical society

  Monthly notices of the royal astronomical society 464 (4), 4866-4874, 2017-02

  Oxford University Press

Keywords

• methods: numerical
• galaxies: evolution
• galaxies: formation

Details

• CRID: 1050845763953085312
• NII Article ID: 120006219984
• HANDLE: 2115/65505
• ISSN: 00358711
• Text Lang: en
• Article Type: journal article
• Data Source:
  • IRDB
  • CiNii Articles