Abstract
Sizes of galaxies are an important diagnostic for galaxy formation models. In
this study I use the abundance matching ansatz, which has proven to be
successful in reproducing galaxy clustering and other statistics, to derive
estimates of the virial radius, R200, for galaxies of different morphological
types and wide range of stellar mass. I show that over eight of orders of
magnitude in stellar mass galaxies of all morphological types follow an
approximately linear relation between half-mass radius of their stellar
distribution, rhalf, and virial radius, rhalf0.015R200, in remarkable
agreement with expectation of models which assume that rhalf lambda R200, where
lambda is the spin of galaxy parent halo. The scatter about the relation is
comparable with the scatter expected from the distribution of lambda and
normalization of the relation agrees with that predicted by the model of Mo,
Mao & White (1998), if galaxy sizes were set on average at z~1-2. Moreover, I
show that when stellar and gas surface density profiles of galaxies of
different morphological types are rescaled using radius r_n= 0.015R200, the
profiles follow approximately universal exponential (for late types) and de
Vaucouleurs (for early types) profiles with scatter of only ~30-50% at
R~1-3r_n. Remarkably, both late and early type galaxies have similar mean
stellar surface density profiles at R>~ 1r_n. The main difference between the
stellar distribution of early and type galaxies is thus at R<r_n.
Description
[1212.2980] The size - virial radius relation of galaxies
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