Bibcode
López-Sanjuan, C.; Balcells, M.; Pérez-González, P. G.; Barro, G.; García-Dabó, C. E.; Gallego, J.; Zamorano, J.
Bibliographical reference
Galaxy Evolution: Emerging Insights and Future Challenges ASP Conference Series, Vol. 419, proceedings of a conference held 11-14 November 2008 at the University of Texas, Austin, Texas, USA. Edited by S. Jogee, I. Marinova, L. Hao, and G. A. Blanc. San Francisco: Astronomical Society of the Pacific, 2009., p.212
Advertised on:
12
2009
Citations
0
Refereed citations
0
Description
We study the evolution of galaxy structure and of the major merger
fraction since z ˜ 1 to present in GOODS-S field for MB
≤ -20 and M* ≥ 1010 Msun
selected galaxies. We segregate the galaxies into early-type galaxies
(ET, E/S0/Sa), and late-type galaxies (LT, Sb-Irr) by their
position in the concentration-asymmetry plane, while we pick up
high asymmetric sources as disk-disk major merger remnants. We
find that the early-type fraction (fET) rises with cosmic
time in both samples. However, the number density evolution is very
different: the decrease in the total number density of MB
≤ -20 galaxies since z = 1 is due to the decrease in the
late-type population, while the increase in the total number density of
M* ≥ 1010 Msun in the same redshift
range is due to early-type evolution. This suggests that we need a
structural transformation between late-type galaxies that form stars
actively and early-type galaxies in which the stellar mass is located.
Comparing the observed evolution with the disk-disk major merger
rate in GOODS-S, we infer that only ˜ 17% of the early-type
galaxies that appear since z = 1 can be explained by these kinds of
mergers, suggesting that minor mergers and secular evolution are the
main processes in the structural evolution of M* ≥
1010 Msun galaxies since z ˜ 1.