Superdense massive galaxies in the Nearby Universe
  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.
