We introduce the The Three Hundred project, an endeavour to model 324 large galaxy clusters with full-physics hydrodynamical re-simulations. Here we present the dataset and study the differences to observations for fundamental galaxy cluster properties and scaling relations. We find that the modelled galaxy clusters are generally in reasonable agreement with observations with respect to baryonic fractions and gas scaling relations at redshift z = 0. However, there are still some (model-dependent) differences, such as central galaxies being too massive, and galaxy colours (g −r) being bluer (about 0.2 dex lower at the peak position) than in observations. The agreement in gas scaling relations down to 10 13 h −1 M between the simulations indicates that particulars of the sub-grid modelling of the baryonic physics only has a weak influence on these relations. We also include -where appropriate -a comparison to three semianalytical galaxy formation models as applied to the same underlying dark matter only simulation. All simulations and derived data products are publicly available.observed properties of the Intra-Cluster Medium (ICM), the size of the central brightest cluster galaxy and the number and properties of the satellite galaxies orbiting within a common dark matter envelope. Clusters of galaxies can therefore be considered to be large cosmological laboratories that are useful for pinning down both cosmological parameters and empirical models of astrophysical processes acting across a range of coupled scales.Concerted effort, from both observational and theoretical perspectives, has been devoted to improve our understanding of the formation and evolution of galaxy clusters. On the observational side, multi-wavelength telescopes are

We present the public release of the MULTIDARK-GALAXIES: three distinct galaxy catalogues derived from one of the Planck cosmology MULTIDARK simulations (i.e. MDPL2, with a volume of (1 h −1 Gpc) 3 and mass resolution of 1.5 × 10 9 h −1 M ) by applying the semi-analytic models GALACTICUS, SAG, and SAGE to it. We compare the three models and their conformity with observational data for a selection of fundamental properties of galaxies like stellar mass function, star formation rate, cold gas fractions, and metallicities -noting that they sometimes perform differently reflecting model designs and calibrations. We have further selected galaxy subsamples of the catalogues by number densities in stellar mass, cold gas mass, and star formation rate in order to study the clustering statistics of galaxies. We show that despite different treatment of orphan galaxies, i.e. galaxies that lost their dark-matter host halo due to the finite mass resolution of the N -body simulation or tidal stripping, the clustering signal is comparable, and reproduces the observations in all three models -in particular when selecting samples based upon stellar mass. Our catalogues provide a powerful tool to study galaxy formation within a volume comparable to those probed by on-going and future photometric and redshift surveys. All model data consisting of a range of galaxy propertiesincluding broad-band SDSS magnitudes -are publicly available.

We use three semi-analytic models (SAMs) of galaxy formation and evolution run on the same 1h−1Gpc MultiDark Planck2 cosmological simulation to investigate the properties of $\left[\rm O\, {\rm {\small II}}\right]$ emission line galaxies at redshift z ∼ 1. We compare model predictions with different observational data sets, including DEEP2–Firefly galaxies with absolute magnitudes. We estimate the $\left[\rm O\, {\rm {\small II}}\right]$ luminosity ($L{\left[\mathrm{O\, {\rm {\small {II}}}}\right]}$) of our model galaxies using the public code get_ emlines, which ideally assumes as input the instantaneous star formation rates (SFRs). This property is only available in one of the SAMs under consideration, while the others provide average SFRs, as most models do. We study the feasibility of inferring galaxies’ $L{\left[\mathrm{O\, {\rm {\small {II}}}}\right]}$  from average SFRs in post-processing. We find that the result is accurate for model galaxies with dust attenuated $L{\left[\mathrm{O\, {\rm {\small {II}}}}\right]}$ ≲ 1042.2erg s−1 ($<5\%$ discrepancy). The galaxy properties that correlate the most with the model $L{\left[\mathrm{O\, {\rm {\small {II}}}}\right]}$ are the SFR and the observed-frame u and g broad-band magnitudes. Such correlations have r-values above 0.64 and a dispersion that varies with $L{\left[\mathrm{O\, {\rm {\small {II}}}}\right]}$. We fit these correlations with simple linear relations and use them as proxies for $L{\left[\mathrm{O\, {\rm {\small {II}}}}\right]}$, together with an observational conversion that depends on SFR and metallicity. These proxies result in $\left[\rm O\, {\rm {\small II}}\right]$ luminosity functions and halo occupation distributions with shapes that vary depending on both the model and the method used to derive $L{\left[\mathrm{O\, {\rm {\small {II}}}}\right]}$. The amplitude of the clustering of model galaxies with $L{\left[\mathrm{O\, {\rm {\small {II}}}}\right]}$ >1040.4erg s−1 remains overall unchanged on scales above 1 h−1Mpc, independently of the $L{\left[\mathrm{O\, {\rm {\small II}}}\right]}$ computation.

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.