The z=0.8 precursors of today's bulges
Abstract
We study the color structure of disk galaxies in the Groth strip at redshifts 0.1<z<1.2. Our aim is to test formation models in which bulges form before/after the disk. We find smooth color distributions with gentle outward blueing across the galaxy image: bulges are not distinctly redder than their disks; and bulge colors strongly correlate with global colors. The results suggest a roughly coeval evolution of bulges and disks. About 50% of the nuclei of galaxies with central light excesses above the outer exponential profile hold passively evolving red populations. The remainder 50% are galaxies with central blue colors similar to their disks. They may be bulges in formation, or the central parts of disks with non-exponential surface brightness profiles.
Keywords
Cite
@article{arxiv.0710.0494,
title = {The z=0.8 precursors of today's bulges},
author = {Marc Balcells and Lilian Dominguez-Palmero},
journal= {arXiv preprint arXiv:0710.0494},
year = {2009}
}
Comments
4 pages, 2 figures, contributed paper to IAU Symposium 245 "Formation and Evolution of Galaxy Bulges", Oxford, 16-20 July 2007