The VIMOS Ultra Deep Survey

Luminosity and stellar mass dependence of galaxy clustering at z ~ 3^★

¹ National Centre for Nuclear Research, ul. Hoza 69, 00-681 Warszawa, Poland
e-mail: anna.durkalec@ncbj.gov.pl
² Aix Marseille Université, CNRS, Laboratoire d’Astrophysique de Marseille, UMR 7326, 13388 Marseille, France
³ Astronomical Observatory of the Jagiellonian University, Orla 171, 30-001 Cracow, Poland
⁴ INAF – Osservatorio Astronomico di Bologna, Via Gobetti 93/3, 40129 Bologna, Italy
⁵ Department of Physics, University of California, Davis, One Shields Ave., Davis, CA 95616, USA
⁶ INAF–IASF Milano, Via Bassini 15, 20133 Milano, Italy
⁷ ESA/ESTEC SCI-S, Keplerlaan 1, 2201 AZ, Noordwijk, The Netherlands
⁸ Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA

Received: 6 March 2017
Accepted: 19 December 2017

Abstract

We present a study of the dependence of galaxy clustering on luminosity and stellar mass in the redshift range 2 < z < 3.5 using 3236 galaxies with robust spectroscopic redshifts from the VIMOS Ultra Deep Survey (VUDS), covering a total area of 0.92 deg². We measured the two-point real-space correlation function w_p(r_p) for four volume-limited subsamples selected by stellar mass and four volume-limited subsamples selected by M_UV absolute magnitude. We find that the scale-dependent clustering amplitude r₀ significantly increases with increasing luminosity and stellar mass. For the least luminous galaxies (M_UV < −19.0), we measured a correlation length r₀ = 2.87 ± 0.22 h⁻¹ Mpc and slope γ = 1.59 ± 0.07, while for the most luminous (M_UV < −20.2) r₀ = 5.35 ± 0.50 h⁻¹ Mpc and γ = 1.92 ± 0.25. These measurements correspond to a strong relative bias between these two subsamples of Δb∕b^* = 0.43. Fitting a five-parameter halo occupation distribution (HOD) model, we find that the most luminous (M_UV < −20.2) and massive (M_⋆ > 10¹⁰ h⁻¹ M_⊙) galaxies occupy the most massive dark matter haloes with ⟨M_h⟩ = 10^12.30 h⁻¹ M_⊙. Similar to the trends observed at lower redshift, the minimum halo mass M_min depends on the luminosity and stellar mass of galaxies and grows from M_min = 10^9.73 h⁻¹ M_⊙ to M_min = 10^11.58 h⁻¹ M_⊙ from the faintest to the brightest among our galaxy sample, respectively. We find the difference between these halo masses to be much more pronounced than is observed for local galaxies of similar properties. Moreover, at z ~ 3, we observe that the masses at which a halo hosts, on average, one satellite and one central galaxy is M₁ ≈ 4M_min over all luminosity ranges, which is significantly lower than observed at z ~ 0; this indicates that the halo satellite occupation increases with redshift. The luminosity and stellar mass dependence is also reflected in the measurements of the large-scale galaxy bias, which we model as b_g,HOD (>L) = 1.92 + 25.36(L/L^*)^7.01. We conclude our study with measurements of the stellar-to-halo mass ratio (SHMR). We observe a significant model-observation discrepancy for low-mass galaxies, suggesting a higher than expected star formation efficiency of these galaxies.