Relations between the Sizes of Galaxies and Their Dark Matter Halos at Redshifts 0 < z < 3

Abstract

We derive relations between the effective radii R eff of galaxies and the virial radii R 200c of their dark matter halos over the redshift range 0 < z < 3. For galaxies, we use the measured sizes from deep images taken with Hubble Space Telescope for the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey; for halos, we use the inferred sizes from abundance matching to cosmological dark matter simulations via a stellar mass-halo mass (SMHM) relation. For this purpose, we derive a new SMHM relation based on the same selection criteria and other assumptions as for our sample of galaxies with size measurements. As a check on the robustness of our results, we also derive R eff -R 200c relations for three independent SMHM relations from the literature. We find that galaxy R eff is proportional on average to halo R 200c , confirming and extending to high redshifts the z = 0 results of Kravtsov. Late-type galaxies (with low Sérsic index and high specific star formation rate [sSFR]) follow a linear R eff -R 200c relation, with effective radii at 0.5 < z < 3 close to those predicted by simple models of disk formation; at z < 0.5, the sizes of late-type galaxies appear to be slightly below this prediction. Early-type galaxies (with high Sérsic index and low sSFR) follow a roughly parallel R eff -R 200c relation, ∼ 0.2-0.3 dex below the one for late-type galaxies. Our observational results, reinforced by recent hydrodynamical simulations, indicate that galaxies grow quasi-homologously with their dark matter halos.

A Model Connecting Galaxy Masses, Star Formation Rates, and Dust Temperatures across Cosmic Time

“…Some simulations suggest that there is significant scatter-about two orders of magnitude -about the mean value of λ (Teklu et al 2015;Zavala et al 2016), and that this scatter depends in part on galaxy morphology (e.g., Teklu et al 2015). The results of Somerville et al (2018), who demonstrate that λ is roughly independent mass and weakly evolves with redshift, are in general agreement with other recent studies of the relationship between galaxy and halo size (e.g., Kawamata et al 2015;Shibuya et al 2015;Huang et al 2017). Yet if our adopted value of λ leads to underestimates or overestimates of R gal for galaxies at certain masses and epochs, these inaccuracies will naturally propagate into our estimates of R dust and τ ν .…”

The size evolution of star-forming and quenched galaxies in the IllustrisTNG simulation

“…Somerville et al (2017) recently extended this kind of analysis up to z ∼ 3 and found proportionality ratios ∼ 2 − 3 times larger, with some variation with mass and redshift. Huang et al (2017) reproduced the Kravtsov (2013) result for early-type galaxies (also up to z ∼ 3) but found an approximately twice larger proportionality value for late-type galaxies. A model like this may account for the scatter in galaxy sizes at a given stellar mass (Somerville et al 2017) and for the stronger size dependence on redshift that is displayed by highermass galaxies (Stringer et al 2014).…”

Angular Momentum of Early- and Late-type Galaxies: Nature or Nurture?

“…In particular, the weak lensing has been exploited to investigate large samples of galaxies via stacking techniques, even at significant redshift z 0.7 (e.g., Hudson et al 2015). Abundance matching also provides insights on the galaxy-to-halo mass ratio at substantial redshift (e.g., Shankar et al 2006;Moster et al 2013;Behroozi et al 2010Behroozi et al , 2013Aversa et al 2015;Huang et al 2017), although the separation between galaxy types is more challenging.…”

“…Most data refer to the central/brightest red galaxy of a halo, possibly corrected for the contribution from satellites. This procedure is quite complex and can significantly contribute to the observed scatter of about 0.2 dex (see Behroozi et al 2013;Reddick et al 2013;Huang et al 2017), as shown by the red shaded area in the top panel of Fig. 1.…”