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An adapted filter function for density split statistics in weak lensing

Burger, P, Schneider, P, Demchenko, V, Harnois-Déraps, J, Heymans, C, Hildebrandt, H and Unruh, S (2020) An adapted filter function for density split statistics in weak lensing. Astronomy and Astrophysics, 642. ISSN 0004-6361

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Abstract

Context. The density split statistics in weak gravitational lensing analyses probes the correlation between regions of different (foreground) galaxy number densities and their weak lensing signal, which is measured by the shape distortion of background galaxies. Aims. In this paper, we reconsider density split statistics, by constructing a new angular filter function that is adapted to the expected relation between the galaxy number density and shear pattern, in a way that the filter weighting the galaxy number density is matched to the filter that is used to quantify the shear signal. Methods. We used the results of numerical ray-tracing simulations, specifically through the Millennium Simulation supplemented by a galaxy distribution based on a semi-analytic model, to construct a matched pair of adapted filter functions for the galaxy density and the tangential shear signal. We compared the performance of our new filter to the previously used top-hat filter, applying both to a different and independent set of numerical simulations (SLICS, cosmo-SLICS). Results. We show that the adapted filter yields a better correlation between the total matter and the galaxy distribution. Furthermore, the adapted filter provides a larger signal-to-noise ratio to constrain the bias between the total matter and the galaxy distribution, and we show that it is, in general, a more sensitive discriminator between different cosmologies, with the exception of cosmologies with very large σ8 values. All analyses lead to the conclusion that our adapted filter should be favoured in future density split statistic works. © ESO 2020.

Item Type: Article
Additional Information: © The European Southern Observatory (ESO)
Uncontrolled Keywords: 0201 Astronomical and Space Sciences
Subjects: Q Science > QB Astronomy
Q Science > QC Physics
Divisions: Astrophysics Research Institute
Publisher: EDP Sciences
Date Deposited: 13 Nov 2020 09:11
Last Modified: 13 Nov 2020 09:15
DOI or Identification number: 10.1051/0004-6361/202038694
URI: https://researchonline.ljmu.ac.uk/id/eprint/13990

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