The imprint of dark matter haloes on the size and velocity dispersion evolution of early-type galaxies

Early-type galaxies (ETGs) are observed to be more compact, on average, at z > 2 than at z=0, at fixed stellar mass. Recent observational works suggest that such size evolution could reflect the similar evolution of the host dark matter halo density as a function of the time of galaxy quenching. We explore this hypothesis by studying the distribution of halo central velocity dispersion (sigmazero) and half-mass radius (rh) as functions of halo mass M and redshift z, in a cosmological LambdaCDM N-body simulation. In the range 02. We conclude that a substantial fraction of the size evolution of ETGs can be ascribed to a systematic dependence on redshift of the dark matter haloes structural properties