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Hubble Frontier Fields: systematic errors in strong lensing models of galaxy clusters – implications for cosmography

Acebron, Ana; Jullo, Eric; Limousin, Marceau; Tilquin, André; Giocoli, Carlo; Jauzac, Mathilde; Mahler, Guillaume; Richard, Johan

Hubble Frontier Fields: systematic errors in strong lensing models of galaxy clusters – implications for cosmography Thumbnail


Authors

Ana Acebron

Eric Jullo

Marceau Limousin

André Tilquin

Carlo Giocoli

Guillaume Mahler

Johan Richard



Abstract

Strong gravitational lensing by galaxy clusters is a fundamental tool to study dark matter and constrain the geometry of the Universe. Recently, the Hubble Space Telescope Frontier Fields programme has allowed a significant improvement of mass and magnification measurements but lensing models still have a residual root mean square between 0.2 arcsec and few arcseconds, not yet completely understood. Systematic errors have to be better understood and treated in order to use strong lensing clusters as reliable cosmological probes. We have analysed two simulated Hubble-Frontier-Fields-like clusters from the Hubble Frontier Fields Comparison Challenge, Ares and Hera. We use several estimators (relative bias on magnification, density profiles, ellipticity and orientation) to quantify the goodness of our reconstructions by comparing our multiple models, optimized with the parametric software LENSTOOL, with the input models. We have quantified the impact of systematic errors arising, first, from the choice of different density profiles and configurations and, secondly, from the availability of constraints (spectroscopic or photometric redshifts, redshift ranges of the background sources) in the parametric modelling of strong lensing galaxy clusters and therefore on the retrieval of cosmological parameters. We find that substructures in the outskirts have a significant impact on the position of the multiple images, yielding tighter cosmological contours. The need for wide-field imaging around massive clusters is thus reinforced. We show that competitive cosmological constraints can be obtained also with complex multimodal clusters and that photometric redshifts improve the constraints on cosmological parameters when considering a narrow range of (spectroscopic) redshifts for the sources.

Citation

Acebron, A., Jullo, E., Limousin, M., Tilquin, A., Giocoli, C., Jauzac, M., …Richard, J. (2017). Hubble Frontier Fields: systematic errors in strong lensing models of galaxy clusters – implications for cosmography. Monthly Notices of the Royal Astronomical Society, 470(2), 1809-1825. https://doi.org/10.1093/mnras/stx1330

Journal Article Type Article
Acceptance Date May 25, 2017
Online Publication Date May 29, 2017
Publication Date Sep 11, 2017
Deposit Date Aug 4, 2017
Publicly Available Date Aug 4, 2017
Journal Monthly Notices of the Royal Astronomical Society
Print ISSN 0035-8711
Electronic ISSN 1365-2966
Publisher Royal Astronomical Society
Peer Reviewed Peer Reviewed
Volume 470
Issue 2
Pages 1809-1825
DOI https://doi.org/10.1093/mnras/stx1330
Public URL https://durham-repository.worktribe.com/output/1352961

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Copyright Statement
This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2017 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.






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