The evolution of clustering length, large-scale bias and host halo mass at 2<z<5 in the VIMOS Ultra Deep Survey (VUDS)

Abstract

We investigate the evolution of galaxy clustering for galaxies in the redshift range 2.0<$z$<5.0 using the VIMOS Ultra Deep Survey (VUDS). We present the projected (real-space) two-point correlation function $w_p(r_p)$ measured by using 3022 galaxies with robust spectroscopic redshifts in two independent fields (COSMOS and VVDS-02h) covering in total 0.8 deg${}^2$. We quantify how the scale dependent clustering amplitude $r_0$ changes with redshift making use of mock samples to evaluate and correct the survey selection function. Using a power-law model $\hat{I}¾(r)=(r/r_0{)}^{-{\hat{I}}^3}$ we find that the correlation function for the general population is best fit by a model with a clustering length $r_0$=3.95${}_{-0.54}^{+0.48}$ h${}^{-1}$Mpc and slope ${\hat{I}}^3$=1.8${}_{-0.06}^{+0.02}$ at $z$~2.5, $r_0$=4.35$\pm$0.60 h${}^{-1}$Mpc and ${\hat{I}}^3$=1.6${}_{-0.13}^{+0.12}$ at $z$~3.5. We use these clustering parameters to derive the large-scale linear galaxy bias $b_L^{PL}$, between galaxies and dark matter. We find $b_L^{PL}$ = 2.68$\pm$0.22 at redshift $z$~3 (assuming $\ddot{I}{ƒ}_8$ = 0.8), significantly higher than found at intermediate and low redshifts. We fit an HOD model to the data and we obtain that the average halo mass at redshift $z$~3 is $M_h$=10${}^{11.75\pm 0.23}$ h${}^{-1}$M${}_{\odot }$. From this fit we confirm that the large-scale linear galaxy bias is relatively high at $b_L^{HOD}$ = 2.82$\pm$0.27. Comparing these measurements with similar measurements at lower redshifts we infer that the star-forming population of galaxies at $z$~3 should evolve into the massive and bright ($M_r$<-21.5) galaxy population which typically occupy haloes of mass $⟨M_h⟩$ = 10${}^{13.9}$ h${}^{-1}$ $M_{\odot }$ at redshift $z$=0.

19 pages, 10 figures, submitted to A&A