Building the red sequence through gas-rich major mergers

Abstract

Understanding the details of how the red sequence is built is a key question in galaxy evolution. What are the relative roles of gas-rich vs. dry mergers, major vs. minor mergers or galaxy mergers vs. gas accretion? In Wild et al. 2009 we compare hydrodynamic simulations with observations to show how gas-rich major mergers result in galaxies with strong post-starburst spectral features, a population of galaxies easily identified in the real Universe using optical spectra. Using spectra from the VVDS deep survey with z~0.7, and a principal component analysis technique to provide indices with high enough SNR, we find that 40% of the mass flux onto the red-sequence could enter through a strong post-starburst phase, and thus through gas-rich major mergers. The deeper samples provided by next generation galaxy redshift surveys will allow us to observe the primary physical processes responsible for the shut-down in starformation and build-up of the red sequence.

4 pages, 7 figures, proceedings of IAU symposium 262 "Stellar populations, planning for the next decade"

References in corpus (5)

• The SWIRE-VVDS-CFHTLS surveys: stellar mass assembly over the last 10 Gyears. Evidence for a major build up of the red sequence between z=2 and z=1
• Equal- and unequal-mass mergers of disk and elliptical galaxies with black holes
• Post-starburst galaxies: more than just an interesting curiosity
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• The VVDS-SWIRE-GALEX-CFHTLS surveys: Physical properties of galaxies at z below 1.2 from photometric data