Expected number of massive galaxy relics in the present-day Universe
  The number of present-day massive galaxies that has survived untouched since
their formation at high-z is an important observational constraint to the
hierarchical galaxy formation models. Using three different semianalytical
models based on the Millenium simulation, we quantify the expected fraction and
number densities of the massive galaxies form at z>2 which have evolved in
stellar mass less than 10% and 30%. We find that only a small fraction of the
massive galaxies already form at z~2 have remained almost unaltered since their
formation (<2% with Delta_M*/M*<0.1 and <8% with Delta_M*/M*<0.3). These
fractions correspond to the following number densities of massive relics in the
present-day Universe: ~1.2x10^-6 Mpc^-3 for Delta_M*/M*<0.1 and ~5.7x10^-6
Mpc^-3 for Delta_M*/M*<0.3. The observed number of relic candidates found in
the nearby Universe is today pretty uncertain (with uncertainties up to a
factor of ~100) preventing to establish a firm conclusion about the goodness of
current theoretical expectations to predict such important number.
