Date Published:

October 1, 2016

Abstract:

We explore the massive bluer star-forming population of the SloanDigital Sky Survey (SDSS) III/BOSS CMASS DR11 galaxies at z > 0.55 toquantify their differences, in terms of redshift-space distortions andlarge-scale bias, with respect to the luminous red galaxy sample. Weperform a qualitative analysis to understand the significance of thesedifferences and whether we can model and reproduce them in mockcatalogues. Specifically, we measure galaxy clustering in CMASS on smalland intermediate scales (0.1 ≲ r ≲ 50 h^-1 Mpc) bycomputing the two-point correlation function - both projected andredshift-space - of these galaxies, and a new statistic, Σ(π),able to separate the coherent and dispersed redshift-space distortioncontributions and the large-scale bias. We interpret our clusteringmeasurements by adopting a Halo Occupation Distribution (HOD) schemethat maps them on to high-resolution N-body cosmological simulations toproduce suitable mock galaxy catalogues. The traditional HODprescription can be applied to the red and the blue samples,independently, but this approach is unphysical since it allows the samemock galaxies to be either red or blue. To overcome this ambiguity, wemodify the standard formulation and infer the red and the blue models bysplitting the full mock catalogue into two complementary andnon-overlapping submocks. This separation is performed by constrainingthe HOD with the observed CMASS red and blue galaxy fractions andproduces reliable and accurate models.

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