The VLT LBG Redshift Survey - I. Clustering and dynamics of ~1000 galaxies at z~3

BIELBY, R; SHANKS, T; WEILBACHER, P; INFANTE, L; CRIGHTON, N; BORNANCINI, C; BOUCHE, N; HÉRAUDEAU, P; LAMBAS, D; LOWENTHAL, J; MINNITI, D; PADILLA, N; PETITJEAN, P; THEUNS, T

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres, Inlgaterra; Año: 2011 vol. 414 p. 2 - 27

0035-8711

We present the initial imaging and spectroscopic data acquired as part of the Very Large Telescope (VLT) VIMOS Lyman-break galaxy Survey. UBR (or UBVI) imaging covers five ~36 × 36 arcmin2 fields centred on bright z > 3 quasi-stellar objects (QSOs), allowing ~21 000 2 < z < 3.5 galaxy candidates to be selected using the Lyman-break technique. We performed spectroscopic follow-up using VLT VIMOS, measuring redshifts for 1020 z > 2 Lyman-break galaxies and 10 z > 2 QSOs from a total of 19 VIMOS pointings. From the galaxy spectra, we observe a 625 ± 510 km s-1 velocity offset between the interstellar absorption and Lyman alpha emission-line redshifts, consistent with previous results. Using the photometric and spectroscopic catalogues, we have analysed the galaxy clustering at z~3. The angular correlation function, w(theta), is well fitted by a double power law with clustering scalelength, r0= 3.19+0.32-0.54 h-1 Mpc and slope γ= 2.45 for r < 1 h-1 Mpc and r0= 4.37+0.43-0.55 h-1 Mpc with γ= 1.61 ± 0.15 at larger scales. Using the redshift sample we estimate the semiprojected correlation function, wp(sigma), and, for a γ= 1.8 power law, find r0= 3.67+0.23-0.24 h-1 Mpc for the VLT sample and r0= 3.98+0.14-0.15 h-1 Mpc for a combined VLT+Keck sample. From ξ(s) and ξ(sigma, pi), and assuming the above ξ(r) models, we find that the combined VLT and Keck surveys require a galaxy pairwise velocity dispersion of ~700 km s-1, higher than ~400 km s-1 assumed by previous authors. We also measure a value for the gravitational growth rate parameter of beta(z= 3) = 0.48 ± 0.17, again higher than that previously found and implying a low value for the bias of b= 2.06+1.1-0.5. This value is consistent with the galaxy clustering amplitude which gives b= 2.22 ± 0.16, assuming the standard cosmology, implying that the evolution of the gravitational growth rate is also consistent with Einstein gravity. Finally, we have compared our Lyman-break galaxy clustering amplitudes with lower redshift measurements and find that the clustering strength is not inconsistent with that of low-redshift L* spirals for simple ´long-lived´ galaxy models. Based on data obtained with the National Optical Astronomy Observatories (NOAO) Mayall 4-m Telescope at Kitt Peak National Observatory, USA (programme ID: 06A-0133), the NOAO Blanco 4-m Telescope at Cerro Tololo Inter-American Observatory, Chile (programme IDs: 03B-0162 and 04B-0022) and the European Southern Observatory (ESO) Very Large Telescope (VLT), Chile (programme IDs: 075.A-0683, 077.A-0612 and 079.A-0442).