Open AccessThe colours of elliptical galaxies
Author(s) -
Chang Ruixiang,
Gallazzi Anna,
Kauffmann Guinevere,
Charlot Stéphane,
Ivezić Željko,
Brinchmann Jarle,
Heckman Timothy M.
Publication year - 2006
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.1365-2966.2005.09778.x
Subject(s) - physics , astrophysics , photometry (optics) , galaxy , velocity dispersion , metallicity , effective radius , elliptical galaxy , stellar mass , sky , astronomy , surface brightness fluctuation , luminous infrared galaxy , lenticular galaxy , star formation , stars
We have compiled a sample of 2728 nearby ( z < 0.08) elliptical galaxies with photometry in the g , r , i , z bands from the Sloan Digital Sky Survey (SDSS) and J , H , K photometry from the Two‐Micron All‐Sky Survey (2MASS). Stellar masses, stellar velocity dispersions and structural parameters such as sizes and surface mass densities are also available for these objects. In order to correct the aperture mismatch between SDSS and 2MASS, we correct the SDSS magnitudes to the isophotal circular radius where the 2MASS magnitudes are measured. We compare the correlations between optical, optical‐infrared and infrared colours and galaxy luminosity, stellar mass, velocity dispersion and surface mass density. We find that all galaxy colours correlate more strongly with stellar mass and velocity dispersion than with any other structural parameter. The dispersion about these two relations is also smaller. We also study the correlations between a variety of stellar absorption‐line indices and the same set of galaxy parameters and we reach very similar conclusions. Finally, we analyse correlations between absorption‐line indices and colour. Our results suggest that the optical colours of elliptical galaxies are sensitive to a combination of age, metallicity and α‐enhancement, while the optical‐infrared colours are sensitive to metallicity and to α‐enhancement, but are somewhat less sensitive to age.