Massive quiescent galaxies at z > 1 have been found to have small physical sizes , hence to be superdense .
Several mechanisms , including minor mergers , have been proposed for increasing galaxy sizes from high- to low-z .
We search for superdense massive galaxies in the WIde-field Nearby Galaxy-cluster Survey ( WINGS ) of X-ray selected galaxy clusters at 0.04 < z < 0.07 .
We discover a significant population of superdense massive galaxies with masses and sizes comparable to those observed at high redshift .
They approximately represent 22 % of all cluster galaxies more massive than 3 \times 10 ^ { 10 } M _ { \odot } , are mostly S0 galaxies , have a median effective radius \langleR _ { e } \rangle = 1.61 \pm 0.29 kpc , a median Sersic index \langle n \rangle = 3.0 \pm 0.6 , and very old stellar populations with a median mass-weighted age of 12.1 \pm 1.3 Gyr .
We calculate a number density of 2.9 \times 10 ^ { -2 } Mpc ^ { -3 } for superdense galaxies in local clusters , and a hard lower limit of 1.3 \times 10 ^ { -5 } Mpc ^ { -3 } in the whole comoving volume between z = 0.04 and z = 0.07 .
We find a relation between mass , effective radius and luminosity-weighted age in our cluster galaxies , which can mimic the claimed evolution of the radius with redshift , if not properly taken into account .
We compare our data with spectroscopic high-z surveys and find that – when stellar masses are considered – there is consistency with the local WINGS galaxy sizes out to z \sim 2 , while a discrepancy of a factor of 3 exists with the only spectroscopic z > 2 study .
In contrast , there is strong evidence for a large evolution in radius for the most massive galaxies with M _ { * } > 4 \times 10 ^ { 11 } M _ { \odot } compared to similarly massive galaxies in WINGS , i.e .
the BCGs .