The Evolution of Passive Galaxies since z=1: Major Mergers vs Secular Processes

López-Sanjuan, C.; Balcells, M.; Pérez-González, Pablo G.; Barro, Guillermo; García-Dabó, C. E.; Gallego, Jesús; Zamorano, Jaime
Bibliographical reference

Stellar Populations – Planning for the Next Decade, Proceedings of the International Astronomical Union, IAU Symposium, Volume 262, p. 209-212

Advertised on:
4
2010
Number of authors
7
IAC number of authors
3
Citations
0
Refereed citations
0
Description
We study the evolution of the red sequence and the blue cloud since z ~ 1 to present in GOODS-S field for MB ≤ -20 and M* ≥ 1010 M&sun; selected galaxies. We segregate the galaxies in early-type galaxies (ET, E/S0/Sa), and late-type galaxies (LT, Sb-Irr) by their position in the concentration-asymmetry plane, while in passive and star-forming by their rest-frame NUV - R color and their 24μm properties. We find that red sequence (passive early types) comoving number density rise with cosmic time in both samples, while blue cloud (star-forming late types) number density descent in luminosity-selected samples and increase in mass-selected sample. We also find a third population that comprises star-forming early-type galaxies. Comparing the observed evolution with the disk-disk (wet) major merger rate in GOODS-S, we infer that only ~20% of M* ≥ 1010 M&sun; red sequence galaxies appeared since z = 1 can be explained by this kind of mergers, suggesting that minor mergers and secular evolution are the main processes in the red sequence evolution of M* ≥ 1010 M&sun; galaxies since z ~ 1.