We present a survey of z \sim 3 Ly \alpha emitters ( LAEs ) within the fields of the VLT LBG Redshift Survey .
The data encompasses 5 independent survey fields co-spatial with spectroscopic LBG data and covering a larger total area than previously analysed for LAE number counts and clustering .
This affords an improved analysis over previous work by minimising the effects of cosmic variance and allowing the cross-clustering analysis of LAEs and LBGs .
Our photometric sample consists of \approx 600 LAE candidates , over an area of 1.07 deg ^ { 2 } , with equivalent widths of \gtrsim 65 Å and a flux limit of \approx 2 \times 10 ^ { -17 } erg cm ^ { -2 } s ^ { -1 } .
From spectroscopic follow-up , we measured a success rate of 78 \pm 18 \% .
We find the R -band continuum luminosity function to be \sim 10 \times lower than the luminosity function of LBGs at this redshift , consistent with previous studies .
Exploiting the large area of the survey , we estimate the LAE auto-correlation function and find a clustering length of r _ { 0 } = 2.86 \pm 0.33 ~ { } h ^ { -1 } Mpc , low compared to the z \sim 3 LBG population , but somewhat higher than previous LAE measurements .
This corresponds to a median halo mass of M _ { DM } = 10 ^ { 11.0 \pm 0.3 } ~ { } h ^ { -1 } ~ { } M _ { \odot } .
We present an analysis of clustering length versus continuum magnitude and find that the measurements for LAEs and LBGs are consistent at faint magnitudes .
Our combined dataset of LAEs and LBGs allows us to measure , for the first time , the LBG-LAE cross-correlation , finding a clustering length of r _ { 0 } = 3.29 \pm 0.57 ~ { } h ^ { -1 } Mpc and a LAE halo mass of 10 ^ { 11.1 \pm 0.4 } ~ { } h ^ { -1 } M _ { \odot } .
Overall , we conclude that LAEs inhabit primarily low mass halos , but form a relatively small proportion of the galaxy population found in such halos .