Massive, red galaxies in a hierarchical universe – I. Counts of extremely red objects and basic properties

Gonzalez-Perez, V.; Baugh, C.M.; Lacey, C.G.; Almeida, C.

Abstract

We present predictions for the abundance and nature of extremely red objects (EROs) in the Λ cold dark matter model. EROs are red, massive galaxies observed at z≥ 1 and their numbers and properties pose a challenge to hierarchical galaxy formation models. We compare the predictions from two published models, one of which invokes a ‘superwind’ to regulate star formation in massive haloes and the other which suppresses gas cooling in haloes through ‘radio-mode’ active galactic nucleus (AGN) feedback. The superwind model underestimates the number counts of EROs by an order of magnitude, whereas the radio-mode AGN feedback model gives excellent agreement with the number counts and redshift distribution of EROs. In the AGN feedback model the ERO population is dominated by old, passively evolving galaxies, whereas observations favour an equal split between old galaxies and dusty starbursts. Also, the model predicts a more extended redshift distribution of passive galaxies than is observed. These comparisons suggest that star formation may be quenched too efficiently in this model.

Citation

Gonzalez-Perez, V., Baugh, C., Lacey, C., & Almeida, C. (2009). Massive, red galaxies in a hierarchical universe – I. Counts of extremely red objects and basic properties. Monthly Notices of the Royal Astronomical Society, 398(2), 497-514. https://doi.org/10.1111/j.1365-2966.2009.14397.x

• Journal Article Type: Article
• Publication Date: Sep 11, 2009
• Deposit Date: Jan 31, 2012
• Publicly Available Date: Jan 29, 2015
• Journal: Monthly Notices of the Royal Astronomical Society
• Print ISSN: 0035-8711
• Electronic ISSN: 1365-2966
• Publisher: Royal Astronomical Society
• Peer Reviewed: Peer Reviewed
• Volume: 398
• Issue: 2
• Pages: 497-514
• DOI: https://doi.org/10.1111/j.1365-2966.2009.14397.x
• Keywords: Galaxies: evolution, Galaxies: formation, Galaxies: high-redshift, Cosmology: theory.
• Public URL: https://durham-repository.worktribe.com/output/1508960