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arXiv · 0710.0494

The z=0.8 precursors of today's bulges

Marc Balcells·Lilian Dominguez-Palmero
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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.

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Marc Balcells, Lilian Dominguez-Palmero. 2007-10-02. The z=0.8 precursors of today's bulges. https://doi.org/10.1017/s1743921308018310

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