The Size Evolution of Galaxies since z~3: Combining SDSS, GEMS, and FIRES
Abstract
We present the evolution of the luminosity-size and stellar mass-size relations of luminous (LV>~3.4×1010 h-270 Lsolar) and massive (M*>~3×1010 h-270 Msolar) galaxies in the last ~11 Gyr. We use very deep near-infrared images of the Hubble Deep Field-South and the MS 1054-03 field in the Js, H, and Ks bands from FIRES to retrieve the sizes in the optical rest frame for galaxies with z>1. We combine our results with those from GEMS at 0.2<z<1 and SDSS at z~0.1 to achieve a comprehensive picture of the optical rest-frame size evolution from z=0 to 3. Galaxies are differentiated according to their light concentration using the Sérsic index n. For less concentrated objects, the galaxies at a given luminosity were typically ~3+/-0.5 (+/-2 σ) times smaller at z~2.5 than those we see today. The stellar mass-size relation has evolved less: the mean size at a given stellar mass was ~2+/-0.5 times smaller at z~2.5, evolving proportionally to (1+z)-0.40+/-0.06. Simple scaling relations between dark matter halos and baryons in a hierarchical cosmogony predict a stronger (although consistent within the error bars) than observed evolution of the stellar mass-size relation. The observed luminosity-size evolution out to z~2.5 matches well recent infall model predictions for Milky Way-type objects. For low-n galaxies, the evolution of the stellar mass-size relation would follow naturally if the individual galaxies grow inside out. For highly concentrated objects, the situation is as follows: at a given luminosity, these galaxies were ~2.7+/-1.1 times smaller at z~2.5 (or, put differently, were typically ~2.2+/-0.7 mag brighter at a given size than they are today), and at a given stellar mass the size has evolved proportionally to (1+z)-0.45+/-0.10.
Based on observations collected at the European Southern Observatory, Paranal, Chile (ESO LP 164.O-0612). Also, based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS 5-26555.- Publication:
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The Astrophysical Journal
- Pub Date:
- October 2006
- DOI:
- 10.1086/506464
- arXiv:
- arXiv:astro-ph/0504225
- Bibcode:
- 2006ApJ...650...18T
- Keywords:
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- Galaxies: Evolution;
- Galaxies: Fundamental Parameters;
- Galaxies: High-Redshift;
- Galaxies: Structure;
- Astrophysics
- E-Print:
- Accepted for publication in ApJ. The new version includes several improvements: much accurate size estimations and a better completeness and robustness analysis. Tables of data are included. 29 pages and 14 figures (one low resolution)