Stochastic bias of colour-selected BAO tracers by joint clustering-weak lensing analysis

Original · EN

The baryon acoustic oscillation (BAO) feature in the two-point correlation function of galaxies supplies a standard ruler to probe the expansion history of the Universe. We study here several galaxy selection schemes, aiming at building an emission-line galaxy (ELG) sample in the redshift range 0.6<z<1.7, that would be suitable for future BAO studies, providing a highly biased galaxy sample. We analyse the angular galaxy clustering of galaxy selections at the redshifts 0.5, 0.7, 0.8, 1 and 1.2 and we combine this analysis with a halo occupation distribution (HOD) model to derive the properties of the haloes these galaxies inhabit, in particular the galaxy bias on large scales. We also perform a weak lensing analysis (aperture statistics) to extract the galaxy bias and the cross-correlation coefficient and compare to the HOD prediction. We apply this analysis on a data set composed of the photometry of the deep co-addition on Sloan Digital Sky Survey (SDSS) Stripe 82 (225 deg²), of Canda-France-Hawai Telescope/Stripe 82 deep i-band weak lensing survey and of the Wide-Field Infrared Survey Explorerinfrared photometric band W1. The analysis on the SDSS-III/constant mass galaxies selection at z=0.5 is in agreement with previous studies on the tracer, moreover we measure its cross-correlation coefficient r=1.16±0.35. For the higher redshift bins, we confirm the trends that the brightest galaxy populations selected are strongly biased (b>1.5), but we are limited by current data sets depth to derive precise values of the galaxy bias. A survey using such tracers of the mass field will guarantee a high significance detection of the BAO.