A new method to measure galaxy bias by combining the density and weak lensing fields

• Published in: Monthly notices of the Royal Astronomical Society 2016-10, Vol.462 (1), p.35-47
• Main Authors: Pujol, Arnau, Chang, Chihway, Gaztañaga, Enrique, Amara, Adam, Refregier, Alexandre, Bacon, David J., Carretero, Jorge, Castander, Francisco J., Crocce, Martin, Fosalba, Pablo, Manera, Marc, Vikram, Vinu
• Format: Article
• Language: English
• Subjects: ASTRONOMY AND ASTROPHYSICS; Bias; Complement; Correlation analysis; cosmology; Density; Estimation bias; Galaxies; gravitational lensing; large-scale structure; Measurement techniques; Mice; Nonlinearity; Parametrization; Red shift; Star & galaxy formation; surveys; Tomography; weak
• ISSN: 0035-8711; 1365-2966
• DOI: 10.1093/mnras/stw1612

We present a new method to measure redshift-dependent galaxy bias by combining information from the galaxy density field and the weak lensing field. This method is based on the work of Amara et al., who use the galaxy density field to construct a bias-weighted convergence field κg. The main difference between Amara et al.'s work and our new implementation is that here we present another way to measure galaxy bias, using tomography instead of bias parametrizations. The correlation between κg and the true lensing field κ allows us to measure galaxy bias using different zero-lag correlations, such as 〈κgκ〉/〈κκ〉 or 〈κgκg〉/〈κgκ〉. Our method measures the linear bias factor on linear scales, under the assumption of no stochasticity between galaxies and matter. We use the Marenostrum Institut de Ciències de l'Espai (MICE) simulation to measure the linear galaxy bias for a flux-limited sample (i