Simultaneous constraints on cosmology and photometric redshift bias from weak lensing and galaxy clustering
Abstract
We investigate the expected cosmological constraints from a combination of cosmic shear and large-scale galaxy clustering using realistic photometric redshift distributions. Introducing a systematic bias in the lensing distributions (of 0.05 in redshift) produces a >2σ bias in the recovered matter power spectrum amplitude and dark energy equation of state for preliminary Stage III surveys. We demonstrate that cosmological error can be largely removed by marginalizing over biases in the assumed weak-lensing redshift distributions. Furthermore, the cosmological constraining power is retained despite removing much of the information on the lensing redshift biases. This finding relies upon high-quality redshift estimates for the clustering sample, but does not require spectroscopy. All galaxies in this analysis can thus be assumed to come from a single photometric survey. We show that this internal constraint on redshift biases arises from complementary degeneracy directions between cosmic shear and the combination of galaxy clustering and shear–density cross-correlations. Finally we examine a case where the assumed redshift distributions differ from the truth by more than a simple uniform bias. We find that the effectiveness of this self-calibration method will depend on the survey details and the nature of the uncertainties on the estimated redshift distributions.
Additional Information
© 2016 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2016 September 28. Received 2016 September 16; in original form 2016 July 28. Published: 30 September 2016. We thank Scott Dodelson, Enrique Gaztanaga, Ashley Ross, Martin Crocce, Eduardo Rozo, Jonathan Blazek, Adam Amara, Benjamin Joachimi, Catherine Heymans, Rachel Mandelbaum, Josh Frieman and the DES MPP group for helpful conversations. SS recognizes receipt of a UK Science and Technology Facilities Council (STFC) Doctoral Training Grant. SLB, MT, JZ and DK acknowledge support from the European Research Council.Attached Files
Published - slw201.pdf
Submitted - 1607.07910.pdf
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Additional details
- Eprint ID
- 79535
- Resolver ID
- CaltechAUTHORS:20170728-103112550
- Science and Technology Facilities Council (STFC)
- European Research Council (ERC)
- Created
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2017-07-28Created from EPrint's datestamp field
- Updated
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2021-11-15Created from EPrint's last_modified field