Superdense massive galaxies (r_e~1 kpc; M~10^{11} Msun) were common in the early universe (z>1.5). Within some hierarchical merging scenarios, a non-negligible fraction (1-10%) of these galaxies is expected to survive since that epoch retaining their compactness and presenting old stellar populations in the present universe. Using the NYU Value-Added Galaxy Catalog from the SDSS Data Release 6 we find only a tiny fraction of galaxies (~0.03%) with r_e<1.5 kpc and M_*>8x10^{10} Msun in the local Universe (z<0.2). Surprinsingly, they are relatively young (~2 Gyr) and metal-rich ([Z/H]~0.2). The consequences of these findings within the current two competing size evolution scenarios for the most massive galaxies ("dry" mergers vs "puffing up" due to quasar activity) are discussed.
@article{arxiv.0901.1032,
title = {Superdense massive galaxies in the Nearby Universe},
author = {Ignacio Trujillo and A. Javier Cenarro and Adriana de Lorenzo-Caceres and Alexandre Vazdekis and Ignacio G. de la Rosa and Antonio Cava},
journal= {arXiv preprint arXiv:0901.1032},
year = {2009}
}
Comments
Accepted for publication in ApJ Letters; 3 figures