2008/04/28 by Mariska Kriek, Arjen van der Wel, Pieter G. van Dokkum +4 · 2 citations
Physics and Astronomy · #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Balmer series #Emission spectrum #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy formation and evolution #Luminous infrared galaxy #Physics #Redshift #Rest frame #Spectral line #Star formation #Stellar mass #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/589677
Accepted for publication in the Astrophysical Journal
arxiv created 2008/04/28 · openalex publication_date 2008/07/29 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
The existence of massive galaxies with strongly suppressed star formation at z ∼ 2.3, identified in a previous paper, suggests that a red sequence may already be in place beyond z = 2. In order to test this hypothesis, we study the rest-frame U − B color distribution of massive galaxies at 2 < z < 3. The sample is drawn from our near-infrared spectroscopic survey for massive galaxies. The color distribution shows a statistically significant (>3 σ) red sequence, which hosts ~60% of the stellar mass at the high-mass end. The red-sequence galaxies have little or no ongoing star formation, as inferred from both emission-line diagnostics and stellar continuum shapes. Their strong Balmer breaks and their location in the rest-frame U − B , B − V plane indicate that they are in a poststarburst phase, with typical ages of ~0.5-1.0 Gyr. In order to study the evolution of the red sequence, we compare our sample with spectroscopic massive galaxy samples at 0.02 < z < 0.045 and 0.6 < z < 1.0. The rest-frame U − B color reddens by ~0.25 mag from z ∼ 2.3 to the present at a given mass. Over the same redshift interval, the number and stellar mass density on the high-mass end (>10 11 M ☉ ) of the red sequence grow by factors of ~8 and ~6, respectively. We explore simple models to explain the observed evolution. Passive evolution models predict too-strong Δ ( U − B ) and produce z ∼ 0 galaxies that are too red. More complicated models that include aging, galaxy transformations, and red mergers can explain both the number density and color evolution of the massive end of the red sequence between z ∼ 2.3 and the present.