A new method to measure galaxy bias

Pollack, Jennifer E, Smith, Robert E and Porciani, Cristiano (2014) A new method to measure galaxy bias. Monthly Notices of the Royal Astronomical Society, 440 (1). pp. 555-576. ISSN 0035-8711

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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 Gpc3, 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.

Item Type: Article
Schools and Departments: School of Mathematical and Physical Sciences > Physics and Astronomy
Subjects: Q Science > QB Astronomy
Depositing User: Richard Chambers
Date Deposited: 05 Aug 2016 14:03
Last Modified: 08 Mar 2017 17:16
URI: http://srodev.sussex.ac.uk/id/eprint/62250

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