Mild Velocity Dispersion Evolution of massive galaxies since z~2

Trujillo, I.; Cenarro, A. J.
Bibliographical reference

Stellar Populations – Planning for the Next Decade, Proceedings of the International Astronomical Union, IAU Symposium, Volume 262, p. 184-187

Advertised on:
4
2010
Number of authors
2
IAC number of authors
2
Citations
1
Refereed citations
1
Description
Making use of public spectra from Cimatti et al. (2008), we measure for the first time the velocity dispersion of spheroid-like massive (M* ~ 1011M&sun;) galaxies at z ~ 1.6. By comparing with galaxies of similar stellar mass at lower redshifts, we find evidence for a mild evolution in velocity dispersion, decreasing from ~240 kms-1 at z ~ 1.6 down to ~180 km s-1 at z ~ 0. Such mild evolution contrasts with the strong change in size (a factor of ~4) found for these type of objects in the same cosmic time, and it is consistent with a progressive larger role, at lower redshift, of the dark matter halo in setting the velocity dispersion of these galaxies. We discuss the implications of our results within the context of different scenarios proposed for the evolution of these massive objects.