Parameter constraints from weak-lensing tomography of galaxy shapes and cosmic microwave background fluctuations

Merkel, Philipp M.; Schäfer, Björn Malte

doi:10.1093/mnras/stx1044

Cited by 14 publications

(10 citation statements)

References 66 publications

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“…However, these higher redshifts are precisely where we expect a cross-correlation signal with CMB lensing. Cross-correlating with the CMB lensing signal will help bring lensing systematics under control [39] to substantially improve the dark energy and neutrino mass figure of merit [15].…”

Section: A Lensing Kernel Pcsmentioning

confidence: 99%

Preparing for the cosmic shear data flood: Optimal data extraction and simulation requirements for stage IV dark energy experiments

2018

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Upcoming photometric lensing surveys will considerably tighten constraints on the neutrino mass and the dark energy equation of state. Nevertheless it remains an open question of how to optimally extract the information and how well the matter power spectrum must be known to obtain unbiased cosmological parameter estimates. By performing a principal component analysis (PCA), we quantify the sensitivity of 3D cosmic shear and tomography with different binning strategies to different regions of the lensing kernel and matter power spectrum, and hence the background geometry and growth of structure in the Universe. We find that a large number of equally spaced tomographic bins in redshift can extract nearly all the cosmological information without the additional computational expense of 3D cosmic shear. Meanwhile a large fraction of the information comes from small poorly understood scales in the matter power spectrum, that can lead to biases on measurements of cosmological parameters. In light of this, we define and compute a cosmology-independent measure of the bias due to imperfect knowledge of the power spectrum. For a Euclid-like survey, we find that the power spectrum must be known to an accuracy of less than 1% on scales with k ≤ 7h Mpc −1 . This requirement is not absolute since the bias depends on the magnitude of modeling errors, where they occur in k-z space, and the correlation between them, all of which are specific to any particular model. We therefore compute the bias in several of the most likely modeling scenarios and introduce a general formalism and public code, RequiSim, to compute the expected bias from any nonlinear model.

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Section: A Lensing Kernel Pcsmentioning

confidence: 99%

Preparing for the cosmic shear data flood: Optimal data extraction and simulation requirements for stage IV dark energy experiments

2018

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“…[24][25][26] and, more recently, in Refs. [27][28][29], while the most advanced and comprehensive studies in the field have been recently published by the DES and SPT collaborations [30,31]; for future galaxy surveys, such as Euclid and LSST, this approach is destined to become the standard baseline analysis to obtain cosmological constraints [15,32,33].…”

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confidence: 99%

CMB lensing reconstruction biases in cross-correlation with large-scale structure probes

Fabbian

Lewis

Beck

2019

J. Cosmol. Astropart. Phys.

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“…The prior treats both cosmological probes as statistically independent. With this set-up properties of intrinsic galaxy ellipticities can be determined at the per cent level (Merkel & Schäfer 2017). Figure 6 shows that ignoring the power spectrum bias, which is almost exclusively negative (cf.…”

Section: Resultsmentioning

confidence: 99%

Imitating intrinsic alignments: a bias to the CMB lensing-galaxy shape cross-correlation power spectrum induced by the large-scale structure bispectrum

Merkel

Schäfer

2017

Monthly Notices of the Royal Astronomical Society

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Cross-correlating the lensing signals of galaxies and comic microwave background (CMB) fluctuations is expected to provide valuable cosmological information. In particular it may help tighten constraints on parameters describing the properties of intrinsically aligned galaxies at high redshift. To access the information conveyed by the cross-correlation signal its accurate theoretical description is required. We compute the bias to CMB lensing-galaxy shape cross-correlation measurements induced by nonlinear structure growth. Using tree-level perturbation theory for the large-scale structure bispectrum we find that the bias is negative on most angular scales, therefore mimicking the signal of intrinsic alignments. Combining Euclid-like galaxy lensing data with a CMB experiment comparable to the Planck satellite mission the bias becomes significant only on smallest scales ( 2500). For improved CMB observations, however, the corrections amount to 10-15 per cent of the CMB lensing-intrinsic alignment signal over a wide multipole range (10 2000). Accordingly the power spectrum bias, if uncorrected, translates into 2σ and 3σ errors in the determination of the intrinsic alignment amplitude in case of CMB stage III and stage IV experiments, respectively.

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Parameter constraints from weak-lensing tomography of galaxy shapes and cosmic microwave background fluctuations

Cited by 14 publications

References 66 publications

Preparing for the cosmic shear data flood: Optimal data extraction and simulation requirements for stage IV dark energy experiments

Preparing for the cosmic shear data flood: Optimal data extraction and simulation requirements for stage IV dark energy experiments

CMB lensing reconstruction biases in cross-correlation with large-scale structure probes

Imitating intrinsic alignments: a bias to the CMB lensing-galaxy shape cross-correlation power spectrum induced by the large-scale structure bispectrum

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