Open AccessKinematic properties and stellar populations of faint early‐type galaxies – I. Velocity dispersion measurements of central Coma galaxies
Author(s) -
Matković A.,
Guzmán R.
Publication year - 2005
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2005.09298.x
Subject(s) - physics , astrophysics , coma cluster , velocity dispersion , elliptical galaxy , galaxy , coma (optics) , fundamental plane (elliptical galaxies) , astronomy , lenticular galaxy , galaxy cluster
We present velocity dispersion measurements for 69 faint early‐type galaxies in the core of the Coma cluster, spanning −22.0 ≲ M R ≲−17.5 mag . We examine the L –σ relation for our sample and compare it to that of bright elliptical galaxies (Es) from the literature. The distribution of the the faint early‐type galaxies in the L –σ plane follows the relation L ∝σ 2.01±0.36 , which is significantly shallower from L ∝σ 4 as defined for the bright Es. While increased rotational support for fainter early‐type galaxies could account for some of the difference in slope, we show that it cannot explain it. We also investigate the colour–σ relation for our Coma galaxies. Using the scatter in this relation, we constrain the range of galaxy ages as a function of their formation epoch for different formation scenarios. Assuming a strong coordination in the formation epoch of faint early‐type systems in Coma, we find that most had to be formed at least 6 Gyr ago and over a short 1‐Gyr period.