A semi-analytical perspective on massive galaxies at z ∼ 0.55

Abstract

The most massive and luminous galaxies in the Universe serve as powerful probes to study the formation of structure, the assembly of mass, and cosmology. However, their detailed formation and evolution is still barely understood. Here we extract a sample of massive mock galaxies from the semi-analytical model of galaxy formation (SAM) Galacticus from the MultiDark-Galaxies, by replicating the CMASS photometric selection from the SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS). The comparison of the Galacticus CMASSmock with BOSS-CMASS data allows us to explore different aspects of the massive galaxy population at 0.5 < z < 0.6, including the galaxy-halo connection and the galaxy clustering. We find good agreement between our modelled galaxies and observations regarding the galaxyhalo connection, but our CMASS-mock over-estimates the clustering amplitude of the 2-point correlation function, due to a smaller number density compared to BOSS, a lack of blue objects, and a small intrinsic scatter in stellar mass at fixed halo mass of < 0.1 dex. To alleviate this problem, we construct an alternative mock catalogue mimicking the CMASS colour-magnitude distribution by randomly down-sampling the SAM catalogue. This CMASS-mock reproduces the clustering of CMASS galaxies within 1σ and shows some environmental dependency of star formation properties that could be connected to the quenching of star formation and the assembly bias.

The effects of peculiar velocities in SN Ia environments on the local H0 measurement

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UV bright red-sequence galaxies: how do UV upturn systems evolve in redshift and stellar mass?

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Building a digital twin of a luminous red galaxy spectroscopic survey: galaxy properties and clustering covariance

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