Quenching versus quiescence: Forming realistic massive ellipticals with a simple starvation model

Thales A. Gutcke, Andrea V. Macciò, Aaron A. Dutton, Greg S. Stinson

Research output: Contribution to journalArticlepeer-review

Abstract

The decrease in star formation (SF) and the morphological change necessary to produce the z = 0 elliptical galaxy population are commonly ascribed to a sudden quenching event, which is able to rid the central galaxy of its cold gas reservoir in a short time. Following this event, the galaxy is able to prevent further SF and stay quiescent via a maintenance mode. We test whether such a quenching event is truly necessary using a simple model of quiescence. In this model, hot gas (all gas above a temperature threshold) in an ∼1012 M halo mass galaxy at redshift z ∼ 3 is prevented from cooling. The cool gas continues to form stars at a decreasing rate and the galaxy stellar mass, morphology, velocity dispersion and position on the colour-magnitude diagram (CMD) proceed to evolve. By z = 0, the halo mass has grown to 1013 M and the galaxy has attained characteristics typical of an observed z = 0 elliptical galaxy. Our model is run in the framework of a cosmological, smooth particle hydrodynamic code that includes SF, early stellar feedback, supernova feedback, metal cooling and metal diffusion. Additionally, we post-process our simulations with a radiative transfer code to create a mock CMD. In contrast to previous assumptions that a pure 'fade away' model evolves too slowly to account for the sparsity of galaxies in the 'green valley', we demonstrate crossing times of ≾1 Gyr. We conclude that no sudden quenching event is necessary to produce such rapid colour transitions.

Original languageEnglish (US)
Pages (from-to)4614-4624
Number of pages11
JournalMonthly Notices of the Royal Astronomical Society
Volume466
Issue number4
DOIs
StatePublished - May 1 2017

Keywords

  • Galaxies: elliptical and lenticular, cD
  • Galaxies: evolution
  • Galaxies: formation
  • Galaxies: stellar content
  • Galaxies: structure
  • Hertzsprung-Russell and colour-magnitude diagrams

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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