SUPERDENSE MASSIVE GALAXIES IN THE NEARBY UNIVERSE

Superdense massive galaxies (r(e) similar to 1 kpc; M similar to 10(11) M(circle dot)) were common in the early universe (z similar to 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 Sloan Digital Sky Survey Data Release 6, we find only a tiny fraction of galaxies (similar to 0.03%) with r(e) less than or similar to 1.5 kpc and M(star) greater than or similar to 8 x 10(10) M(circle dot) in the local universe (z < 0.2). Surprisingly, they are relatively young (similar to 2 Gyr) and metal-rich ([Z/H] similar to 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.