Stellar property statistics of massive haloes from cosmological hydrodynamics simulations: common kernel shapes
Abstract
We study stellar property statistics, including satellite galaxy occupation, of haloes in three cosmological hydrodynamics simulations: BAHAMAS + MACSIS, IllustrisTNG, and Magneticum Pathfinder. Applying localized linear regression, we extract halo massconditioned normalizations, slopes, and intrinsic covariance for (i) N_{sat}, the number of stellar massthresholded satellite galaxies within radius R_{200c} of the halo; (ii) M_{⋆,tot}, the total stellar mass within that radius, and (iii) M_{⋆,BCG}, the gravitationally bound stellar mass of the central galaxy within a 100 kpc radius. The parameters show differences across the simulations, in part from numerical resolution, but there is qualitative agreement for the N_{sat}  M_{⋆,BCG} correlation. Marginalizing over M_{halo}, we find the N_{sat} kernel, p(ln N_{sat}  M_{halo,z}) to be consistently skewed left in all three simulations, with skewness parameter γ = 0.91 ± 0.02, while the M_{⋆,tot} kernel shape is closer to lognormal. The highest resolution simulations find γ ≃ 0.8 for the z = 0 shape of the M_{⋆,BCG} kernel. We provide a Gaussian mixture fit to the lowredshift N_{sat} kernel as well as local linear regression parameters tabulated for M_{halo} > 10^{13.5} M⊙ in all simulations.
 Publication:

Monthly Notices of the Royal Astronomical Society
 Pub Date:
 June 2020
 DOI:
 10.1093/mnras/staa1147
 arXiv:
 arXiv:2001.02283
 Bibcode:
 2020MNRAS.495..686A
 Keywords:

 methods: statistical;
 galaxies: clusters: general;
 galaxies: evolution;
 galaxies: haloes;
 Astrophysics  Astrophysics of Galaxies;
 Astrophysics  Cosmology and Nongalactic Astrophysics
 EPrint:
 17 pages, 15 figures