2009/02/28 by A. Javier Cenarro, Ignacio Trujillo · 3 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Context (archaeology) #Dark matter #Dark matter halo #Dispersion (optics) #Electrical and Electromagnetic Research #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy formation and evolution #Halo #Velocity dispersion #astro-ph.CO
paper · pdf · doi:10.1088/0004-637x/696/1/l43
5 pages, 2 Figures. Accepted in ApJL. Minor changes from former submission
arxiv created 2009/03/25 · openalex publication_date 2009/04/09 · arxiv updated 2015/05/12 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Making use of public spectra from Cimatti et al., we measure for the first time the velocity dispersion of spheroid-like massive ( M ⋆ ∼ 10 11 M ☉ ) 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 km s −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.