The galaxy size–halo mass scaling relations and clustering properties of central and satellite galaxies

RODRIGUEZ, FACUNDO; MONTERO-DORTA, ANTONIO D; ANGULO, RAUL E; ARTALE, M CELESTE; MERCHÁN, MANUEL

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY

WILEY-BLACKWELL PUBLISHING, INC

Año: 2021 vol. 505 p. 3192 - 3205

0035-8711

In this work, we combine size and stellar mass measurements from the Sloan Digital SkyServer (SDSS) with the group finder algorithm of Rodriguez & Merchán in order to determinethe stellar and halo mass ? size relations of central and satellite galaxies separately. We showthat, while central and satellite galaxies display similar stellar mass ? size relations, their halomass ? size relations differ significantly. As expected, more massive haloes tend to host largercentral galaxies. However, the size of satellite galaxies depends only slightly on halo virialmass. We show that these results are compatible with a remarkably simple model in whichthe size of central and satellite galaxies scales as the cubic root of their host halo mass, withthe normalization for satellites being ∼ 30 % smaller than that for central galaxies, whichcan be attributed to tidal stripping. We further check that our measurements are in excellentagreement with predictions from the IllustrisTNG hydrodynamical simulation. In the secondpart of this paper, we analyse how the clustering properties of central and satellite galaxiesdepend on their size. We demonstrate that, independently of the stellar mass threshold adopted,smaller galaxies are more tightly clustered than larger galaxies when either the entire sampleor only satellites are considered. The opposite trend is observed on large scales when thesize split is performed for the central galaxies alone. Our results place significant constraintsfor halo?galaxy connection models that link galaxy size with the properties of their hostinghaloes.