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 {x} 36 arcmin
2 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 velocity offset between the interstellar absorption and Lyman α 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(θ), is well fitted by a double power law with clustering scalelength,
r0= 3.19
+0.32–0.54h
–1 Mpc and slope γ= 2.45 for
r < 1
h–1 Mpc and
r0= 4.37
+0.43–0.55h
–1 Mpc with γ= 1.61±0.15 at larger scales. Using the redshift sample we estimate the semiprojected correlation function,
wp(σ), and, for a γ= 1.8 power law, find
r0= 3.67
+0.23–0.24h
–1 Mpc for the VLT sample and
r0= 3.98
+0.14–0.15h
–1 Mpc for a combined VLT+Keck sample. From ξ(
s) and ξ(σ, π), 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, higher than ≈ 400 km/s assumed by previous authors. We also measure a value for the gravitational growth rate parameter of β(
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). The VLT LBG Redshift Survey– II. Interactions between galaxies and the IGM at
z∼ 3