Year: 2013
Type: article
Abstract: 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, R 200 , for galaxies of different morphological types and a wide range of stellar masses. I show that over eight orders of magnitude in stellar mass galaxies of all morphological types follow an approximately linear relation between half-mass radius of their stellar distribution, r 1/2 , and virial radius, r 1/2 ≈ 0.015 R 200 , with scatter of ≈0.2 dex. Such scaling is in remarkable agreement with the expectation of models that assume that galaxy sizes are controlled by halo angular momentum, r 1/2 ∝λ R 200 , where λ is the spin of galaxy parent halo. The scatter about the relation is comparable with the scatter expected from the distribution of λ. Moreover, I show that when the stellar and gas surface density profiles of galaxies of different morphological types are rescaled by the radius r n = 0.015 R 200 , the rescaled profiles follow approximately universal exponential (for late types) and de Vaucouleurs (for early types) form with scatter of only ≈30%–50% at R ≈ 1–3 r n . Remarkably, both late- and early-type galaxies have similar mean stellar surface density profiles at R ≳ 1 r n . The main difference between their stellar distributions is thus at R < r n . The results of this study imply that galaxy sizes and radial distribution of baryons are shaped primarily by properties of their parent halos and that the sizes of both late-type disks and early-type spheroids are controlled by halo angular momentum.
Author: Andrey V. Kravtsov
Institution: University of Chicago
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W2008953099