Christopher Duncan: Publications

Cluster mass profile reconstruction with size and flux magnification on the HST STAGES survey

Monthly Notices of the Royal Astronomical Society 91̽�� University Press (OUP) 457:1 (2016) 764-785

Authors:

Christopher AJ Duncan, Catherine Heymans, Alan F Heavens, Benjamin Joachimi

On the complementarity of galaxy clustering with cosmic shear and flux magnification

Monthly Notices of the Royal Astronomical Society 91̽�� University Press (OUP) 437:3 (2014) 2471-2487

Authors:

Christopher AJ Duncan, Benjamin Joachimi, Alan F Heavens, Catherine Heymans, Hendrik Hildebrandt

Cosmic magnification as a probe of cosmology

Proceedings of the 47th Rencontres de Moriond on Cosmology 2012 (2012) 173-176

Authors:

C Duncan, A Heavens, B Joachimi, C Heymans

Abstract:

With the wealth of upcoming data from wide-field surveys such as KiDS, Pan-STARRS, DES and Euclid, it is more important than ever to understand the full range of independent probes of cosmology at our disposal. With this in mind, we motivate the use of cosmic magnification as a probe of cosmology, presenting forecasts for the improvements to cosmic shear cosmological parameter constraints when cosmic magnification is included for a KiDS-like survey. We find that when uncertainty in the galaxy bias is factored into the forecasts, cosmic magnification is less powerful that previously reported, but as it is less likely to be prone to measurement error we conclude it is a useful tool for cosmological analyses.

Euclid preparation: VI. Verifying the Performance of Cosmic Shear Experiments

Authors:

Euclid Collaboration, P Paykari, Td Kitching, H Hoekstra, R Azzollini, Vf Cardone, M Cropper, Caj Duncan, A Kannawadi, L Miller, H Aussel, If Conti, N Auricchio, M Baldi, S Bardelli, A Biviano, D Bonino, E Borsato, E Bozzo, E Branchini, S Brau-Nogue, M Brescia, J Brinchmann, C Burigana, S Camera, V Capobianco, C Carbone, J Carretero, Fj Castander, M Castellano, S Cavuoti, Y Charles, R Cledassou, C Colodro-Conde, G Congedo, C Conselice, L Conversi, Y Copin, J Coupon, Hm Courtois, A Da Silva, X Dupac, G Fabbian, S Farrens, Pg Ferreira, P Fosalba, N Fourmanoit, M Frailis, M Fumana, S Galeotta

Abstract:

Our aim is to quantify the impact of systematic effects on the inference of cosmological parameters from cosmic shear. We present an end-to-end approach that introduces sources of bias in a modelled weak lensing survey on a galaxy-by-galaxy level. Residual biases are propagated through a pipeline from galaxy properties (one end) through to cosmic shear power spectra and cosmological parameter estimates (the other end), to quantify how imperfect knowledge of the pipeline changes the maximum likelihood values of dark energy parameters. We quantify the impact of an imperfect correction for charge transfer inefficiency (CTI) and modelling uncertainties of the point spread function (PSF) for Euclid, and find that the biases introduced can be corrected to acceptable levels.

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