Cosmic magnification: nulling intrinsic clustering

Alan F. Heavens, Benjamin Joachimi

Research output: Contribution to journalArticlepeer-review


We investigate the extent to which the pure magnification effect of gravitational lensing can be extracted from galaxy clustering statistics, by a nulling method which aims to eliminate terms arising from the intrinsic clustering of galaxies. The aim is to leave statistics which are free from the uncertainties of galaxy bias. We find that nulling can be done effectively, leaving data which are relatively insensitive to uncertainties in galaxy bias and its evolution, leading to cosmological parameter estimation which is effectively unbiased. This advantage comes at the expense of increased statistical errors, which are in some cases large, but it offers a robust alternative analysis method to cosmic shear for cosmological imaging surveys designed for weak-lensing studies, or to full modelling of the clustering signal including magnification effects.
Original languageEnglish
Pages (from-to)1681-1690
JournalMonthly Notices of the Royal Astronomical Society
Publication statusPublished - 1 Aug 2011


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