We investigate how the lensing potential can be measured tomographically with future galaxy surveys using their number counts.

Such a measurement is an independent test of the standard ΛCDM framework and can be used to discern modified theories of gravity.

We perform a Fisher matrix forecast based on galaxy angular-redshift power spectra, assuming specifications consistent with future photometric Euclid-like surveys and spectroscopic SKA-like surveys.

For the Euclid-like survey we derive a fitting formula for the magnification bias.

Our analysis suggests that the cross correlation between different redshift bins is very sensitive to the lensing potential such that the survey can measure the amplitude of the lensing potential at the same level of precision as other standard ΛCDM cosmological parameters.

# Measuring the lensing potential with tomographic galaxy number counts

Date:

4. June 2015

Cite as:

F. Montanari and R. Durrer, [arXiv:1506.01369].

Online abstract:

Members involved:

Summary:

## Address

Département de Physique Théorique

Université de Genève

24, quai Ernest Ansermet

1211 Genève 4

Switzerland

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