A new method to measure galaxy bias. Issue 1 (12th March 2014)

• Record Type: Journal Article
• Authors: Pollack, Jennifer E.; Smith, Robert E.; Porciani, Cristiano
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 440:Issue 1(2014)
• Page Start: 555
• Page End: 576
• Publication Date: 2014-03-12
• Subjects: cosmology: theory -- large-scale structure of Universe; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/stu322
• Languages: English
• ISSNs: 0035-8711

Abstract

Abstract: We present a new approach for modelling galaxy/halo bias that utilizes the full non-linear information contained in the moments of the matter density field, which we derive using a set of numerical simulations. Although our method is general, we perform a case study based on the local Eulerian bias scheme truncated to second order. Using 200 N -body simulations covering a total comoving volume of 675 h −3 Gpc 3, we measure several two- and three-point statistics of the halo distribution to unprecedented accuracy. We use the bias model to fit the halo–halo power spectrum, the halo–matter cross-spectrum and the corresponding three bispectra for wavenumbers in the range 0.04 ≲ k ≲ 0.12 h Mpc −1 . We find that the constraints on the bias parameters obtained using the full non-linear information differ significantly from those derived using standard perturbation theory at leading order. Hence, neglecting the full non-linear information leads to biased results for this particular scale range. We also test the validity of the second-order Eulerian local biasing scheme by comparing the parameter constraints derived from different statistics. Analysis of the halo–matter cross-correlation coefficients defined for the two- and three-point statistics reveals further inconsistencies contained in the second-order Eulerian bias scheme, suggesting it is too simple a model to describe halo bias with high accuracy.