Sign on
ADS Classic is now deprecated. It will be completely retired in October 2019. This page will automatically redirect to the new ADS interface at that point.

SAO/NASA ADS Astronomy Abstract Service


· Find Similar Abstracts (with default settings below)
· Electronic Refereed Journal Article (HTML)
· Full Refereed Journal Article (PDF/Postscript)
· arXiv e-print (arXiv:1712.04923)
· References in the article
· Citations to the Article (14) (Citation History)
· Refereed Citations to the Article
· Also-Read Articles (Reads History)
·
· Translate This Page
Title:
The skewed weak lensing likelihood: why biases arise, despite data and theory being sound
Authors:
Sellentin, Elena; Heymans, Catherine; Harnois-Déraps, Joachim
Affiliation:
AA(Département de Physique Théorique, Université de Genèe, 24 Quai Ernest-Ansermet, CH-1211 Genèe, Switzerland), AB(Scottish Universities Physics Alliance, Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, UK), AC(Scottish Universities Physics Alliance, Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, UK)
Publication:
Monthly Notices of the Royal Astronomical Society, Volume 477, Issue 4, p.4879-4895 (MNRAS Homepage)
Publication Date:
07/2018
Origin:
OUP
Astronomy Keywords:
methods: data analysis, methods: statistical, cosmology: observations
Abstract Copyright:
2018 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society
DOI:
10.1093/mnras/sty988
Bibliographic Code:
2018MNRAS.477.4879S

Abstract

We derive the essentials of the skewed weak lensing likelihood via a simple hierarchical forward model. Our likelihood passes four objective and cosmology-independent tests which a standard Gaussian likelihood fails. We demonstrate that sound weak lensing data are naturally biased low, since they are drawn from a skewed distribution. This occurs already in the framework of Lambda cold dark matter. Mathematically, the biases arise because noisy two-point functions follow skewed distributions. This form of bias is already known from cosmic microwave background analyses, where the low multipoles have asymmetric error bars. Weak lensing is more strongly affected by this asymmetry as galaxies form a discrete set of shear tracer particles, in contrast to a smooth shear field. We demonstrate that the biases can be up to 30 per cent of the standard deviation per data point, dependent on the properties of the weak lensing survey and the employed filter function. Our likelihood provides a versatile framework with which to address this bias in future weak lensing analyses.
Bibtex entry for this abstract   Preferred format for this abstract (see Preferences)


Find Similar Abstracts:

Use: Authors
Title
Keywords (in text query field)
Abstract Text
Return: Query Results Return    items starting with number
Query Form
Database: Astronomy
Physics
arXiv e-prints