TY - JOUR
T1 - A new method to measure galaxy bias by combining the density and weak lensing fields
AU - Pujol, Arnau
AU - Chang, Chihway
AU - Gaztañaga, Enrique
AU - Amara, Adam
AU - Refregier, Alexandre
AU - Bacon, David J.
AU - Carretero, Jorge
AU - Castander, Francisco J.
AU - Crocce, Martin
AU - Fosalba, Pablo
AU - Manera, Marc
AU - Vikram, Vinu
PY - 2016/10/11
Y1 - 2016/10/11
N2 - © 2016 The Authors. We present a newmethod 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〉/〈κ κ〉 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 Ciéncies de l'Espai (MICE) simulation tomeasure the linear galaxy bias for a flux-limited sample (i < 22.5) in tomographic redshift bins using this method. This article is the first that studies the accuracy and systematic uncertainties associated with the implementation of the method and the regime in which it is consistent with the linear galaxy bias defined by projected two-point correlation functions (2PCF). We find that our method is consistent with a linear bias at the per cent level for scales larger than 30 arcmin, while non-linearities appear at smaller scales. This measurement is a good complement to other measurements of bias, since it does not depend strongly on s8 as do the 2PCF measurements. We will apply this method to the Dark Energy Survey Science Verification data in a follow-up article.
AB - © 2016 The Authors. We present a newmethod 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〉/〈κ κ〉 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 Ciéncies de l'Espai (MICE) simulation tomeasure the linear galaxy bias for a flux-limited sample (i < 22.5) in tomographic redshift bins using this method. This article is the first that studies the accuracy and systematic uncertainties associated with the implementation of the method and the regime in which it is consistent with the linear galaxy bias defined by projected two-point correlation functions (2PCF). We find that our method is consistent with a linear bias at the per cent level for scales larger than 30 arcmin, while non-linearities appear at smaller scales. This measurement is a good complement to other measurements of bias, since it does not depend strongly on s8 as do the 2PCF measurements. We will apply this method to the Dark Energy Survey Science Verification data in a follow-up article.
KW - gravitational lensing: weak
KW - Large-scale structure of Universe
KW - Surveys
U2 - 10.1093/mnras/stw1612
DO - 10.1093/mnras/stw1612
M3 - Article
VL - 462
SP - 35
EP - 47
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
SN - 0035-8711
IS - 1
ER -