Modeling the red sequence: Hierarchical growth yet slow luminosity evolution

Abstract

We explore the effects of mergers on the evolution of massive early-type galaxies by modeling the evolution of their stellar populations in a hierarchical context. We investigate how a realistic red sequence population set up by z~1 evolves under different assumptions for the merger and star formation histories, comparing changes in color, luminosity and mass. The purely passive fading of existing red sequence galaxies, with no further mergers or star formation, results in dramatic changes at the bright end of the luminosity function and color-magnitude relation. Without mergers there is too much evolution in luminosity at a fixed space density compared to observations. The change in color and magnitude at a fixed mass resemble that of a passively evolving population that formed relatively recently, at z~2. Mergers amongst the red sequence population ("dry mergers") occurring after z=1 build up mass, counteracting the fading of the existing stellar populations to give smaller changes in both color and luminosity for massive galaxies. By allowing some galaxies to migrate from the blue cloud onto the red sequence after z=1 through gas-rich mergers, younger stellar populations are added to the red sequence. This manifestation of the progenitor bias increases the scatter in age and results in even smaller changes in color and luminosity between z=1 and z=0 at a fixed mass. The resultant evolution appears much slower, resembling the passive evolution of a population that formed at high redshift (z~3-5) and is in closer agreement with observations. Measurements of the luminosity and color evolution alone are not sufficient to distinguish between the purely passive evolution of an old population and cosmologically motivated hierarchical growth, although these scenarios have very different implications for the mass growth of early-type galaxies over the last half of cosmic history.

14 pages, 4 figures. Final version accepted for publication in ApJ (2012, ApJ 753, 44)

References in corpus (10)

• The Mass-Metallicity Relation at z~2
• Detection of quiescent galaxies in a bicolor sequence from z=0-2
• The Redshift Evolution of Wet, Dry, and Mixed Galaxy Mergers from Close Galaxy Pairs in the DEEP2 Galaxy Redshift Survey
• Star Formation and the Growth of Stellar Mass
• The Detection of a Red Sequence of Massive Field Galaxies at z~2.3 and its Evolution to z~0
• The Star Formation Epoch of the Most Massive Early-Type Galaxies
• The Pair Fraction of Massive Galaxies at 0 < z < 3
• Luminosity Function Constraints on the Evolution of Massive Red Galaxies Since z~0.9
• M/L and Color Evolution for A Deep Sample of M* Cluster Galaxies at z~1: The Formation Epoch and the Tilt of the Fundamental Plane
• Evolution of the Stellar Mass-Metallicity Relation Since z=0.75

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