The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: Modeling the clustering and halo occupation distribution of BOSS-CMASS galaxies in the Final Data Release

TL;DR

This work tests Halo Abundance Matching (HAM) on a large cosmological simulation to reproduce the clustering of SDSS-III/BOSS CMASS galaxies in the redshift range $0.43<z<0.7$, by constructing realistic light-cone mocks with survey geometry, incompleteness, and fiber-collision modeling. The SUrvey GenerAtoR (SUGAR) tool implements HAM on the BigMultiDark Planck simulation, matching the stellar mass function and generating 100 md-patchy mocks to quantify covariance. The model reproduces the observed monopole of the 2-point correlation function and the galaxy power spectrum up to $k\sim1\,h\mathrm{Mpc}^{-1}$, and yields good agreement for the 3-point function and the stellar-to-halo mass relation, though the quadrupole shows tensions likely due to systematics and possible velocity bias. The results validate HAM as an effective framework for CMASS clustering studies and produce publicly available BigMD-BOSS light-cones for community use.

Abstract

We present a study of the clustering and halo occupation distribution of BOSS CMASS galaxies in the redshift range 0.43 < z < 0.7 drawn from the Final SDSS-III Data Release. We compare the BOSS results with the predictions of a Halo Abundance Matching (HAM) clustering model that assigns galaxies to dark matter halos selected from the large BigMultiDark $N$-body simulation of a flat $Λ$CDM Planck cosmology. We compare the observational data with the simulated ones on a light-cone constructed from 20 subsequent outputs of the simulation. Observational effects such as incompleteness, geometry, veto masks and fiber collisions are included in the model, which reproduces within 1-$σ$ errors the observed monopole of the 2-point correlation function at all relevant scales: from the smallest scales, 0.5 $h^{-1}$ Mpc, up to scales beyond the Baryonic Acoustic Oscillation feature. This model also agrees remarkably well with the BOSS galaxy power spectrum (up to $k\sim1$ $h$ Mpc$^{-1}$), and the Three-point correlation function. The quadrupole of the correlation function presents some tensions with observations. We discuss possible causes that can explain this disagreement, including target selection effects. Overall, the standard HAM model describes remarkably well the clustering statistics of the CMASS sample. We compare the stellar to halo mass relation for the CMASS sample measured using weak lensing in the CFHT Stripe 82 Survey with the prediction of our clustering model, and find a good agreement within 1-$σ$. The BigMD-BOSS light-cone including properties of BOSS galaxies and halo properties is made publicly available.

Figures (15)

• Figure 1: $Left$$panel$: Sky area covered by the BigMD-BOSS light-cone. This region includes the BOSS CMASS DR12 geometry and veto masks. $Right$$panel$: Sky area covered by the BOSS CMASS DR12 sample. Colours indicate the angular number density, which is normalised by the most dense pixel. Each pixel has an angular area of 1 deg$^2$. BigMD-BOSS light-cone uses the same mask as the BOSS CMASS DR12, including angular completeness and veto masks.
• Figure 2: Pie plot of the BigMD-BOSS light-cone (left panel) and the BOSS CMASS DR12 data (right panel). Both figures were made with 2 deg of thickness (DEC coordinate).
• Figure 3: Stellar mass function from BOSS CMASS DR12 sample. Circles and squares show the stellar mass distribution for two redshift bins from the Portsmouth DR12 catalogue. Poissonian errors are included. The solid line shows the estimate of the SMF for this work, which is constructed combining the high-mass end of the BOSS sample and guo2010 for the low-mass range ($\log_{10}M*<11.0$). In order to compare with a complete sample in the redshift range 0.5 to 0.65, we include the PRIMUS SMF (Triangles) in the low-mass regime.
• Figure 4: The comoving number density of BOSS CMASS DR12 NGC (black line) compared to the comoving number density of the BigMD-BOSS light-cone (Dashed line). Shaded area comes from 100 md-patchy Mocks.
• Figure 5: Incompleteness modelling for three different redshift bins. Shaded area shows the BigMD-BOSS light-cone, dots are the measurements from the CMASS Portsmouth catalogue. In both cases Poissonian errors are used. Dashed line represents the SMF adopted in this work. We select three bins as an example to show the results of the incompleteness modelling implemented in this work. Stellar mass distribution in the BigMD-BOSS light-cone are produced by downsampling galaxies from the SMF adopted. Left panel figure shows the incompleteness at low-redshift in the high-mass of the SMF.