English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The mass and structural assembly of galaxies is a matter of intense debate.Current theoretical models predict the existence of a linear relationshipbetween galaxy size ($R_e$) and the host dark matter halo virial radius($R_h$).\\ By making use of semi-empirical models compared to the sizedistributions of central galaxies from the Sloan Digital Sky Survey, we providerobust constraints on the normalization and scatter of the $R_e-R_h$ relation.We explore the parameter space of models in which the $R_e-R_h$ relation ismediated by either the spin parameter or the concentration of the host halo, ora simple constant the nature of which is in principle unknown. We find that thedata require extremely tight relations for both early-type and late-typegalaxies (ETGs,LTGs), especially for more massive galaxies. These constraintschallenge models based solely on angular momentum conservation, which predictsignificantly wider distributions of galaxy sizes and no trend with stellarmass, if taken at face value. We discuss physically-motivated alterations tothe original models that bring the predictions into better agreement with thedata. We argue that the measured tight size distributions of SDSS disk galaxiescan be reproduced by semi-empirical models in which the $R_e-R_h$ connection ismediated by the \emph{stellar} specific angular momenta $j_{star}.$ We findthat current cosmological models of galaxy formation broadly agree with ourconstraints for LTGs, and justify the strong link between $R_e$ and $j_{star}$that we propose, however the tightness of the $R_e-R_h$ relation found in suchab-initio theoretical models for ETGs is in tension with our semi-empiricalfindings.

Galaxy sizes and the galaxy-halo connection -- I: the remarkable tightness of the size distributions