Journal Article

Photometric and clustering properties of hydrodynamical galaxies in a cosmological volume: results at <i>z</i>= 0

Sebastián E. Nuza, Klaus Dolag and Alexandro Saro

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 407, issue 3, pages 1376-1386
Published in print September 2010 | ISSN: 0035-8711
Published online September 2010 | e-ISSN: 1365-2966 | DOI:
Photometric and clustering properties of hydrodynamical galaxies in a cosmological volume: results at z= 0

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In this work, we present results for the photometric and clustering properties of galaxies that arise in a Λ cold dark matter hydrodynamical simulation of the local Universe. The present-day distribution of matter was constructed to match the observed large-scale pattern of the IRAS 1.2-Jy galaxy survey. Our simulation follows the formation and evolution of galaxies in a cosmological sphere with a volume of ∼1303 h−3 Mpc3 including supernova feedback, galactic winds, photoheating due to a uniform meta-galactic background and chemical enrichment of the gas and stellar populations. However, we do not consider active galactic nuclei. In the simulation, a total of ∼20 000 galaxies are formed above the resolution limit, and around 60 haloes are more massive than ∼1014 M. Luminosities of the galaxies are calculated based on a stellar population synthesis model including the attenuation by dust, which is calculated from the cold gas left within the simulated galaxies. Environmental effects such as colour bimodality and differential clustering power of the hydrodynamical galaxies are qualitatively similar to observed trends. Nevertheless, the overcooling present in the simulations leads to too blue and overluminous brightest cluster galaxies (BCGs). To overcome this, we mimic the late-time suppression of star formation in massive haloes by ignoring recently formed stars with the aid of a simple post-processing recipe. In this way we find luminosity functions, both for field and for group/cluster galaxies, in better agreement with observations. Specifically, the BCGs then follow the observed luminosity–halo mass relation. However, in such a case, the colour bimodality is basically lost, pointing towards a more complex interplay of late suppression of star formation than what is given by the simple scheme adopted.

Keywords: hydrodynamics; methods: numerical; galaxies: evolution; galaxies: formation; cosmology: theory

Journal Article.  7291 words.  Illustrated.

Subjects: Astronomy and Astrophysics

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