KiDS-450: Cosmological parameter constraints from tomographic weak gravitational lensing

H. Hildebrandt, M. Viola, C. Heymans, S. Joudaki, K. Kuijken, C. Blake, T. Erben, B. Joachimi, D. Klaes, L. Miller, C. B. Morrison, R. Nakajima, G. Verdoes Kleijn, A. Amon, A. Choi, G. Covone, J. T.A. de Jong, A. Dvornik, I. Fenech Conti, A. GradoJ. Harnois-Déraps, R. Herbonnet, H. Hoekstra, F. Köhlinger, J. McFarland, A. Mead, J. Merten, N. Napolitano, J. A. Peacock, M. Radovich, P. Schneider, P. Simon, E. A. Valentijn, J. L. van den Busch, E. van Uitert, L. Van Waerbeke

Research output: Contribution to journalArticlepeer-review

139 Scopus citations

Abstract

We present cosmological parameter constraints from a tomographic weak gravitational lensing analysis of ~450 deg2 of imaging data from the Kilo Degree Survey (KiDS). For a at ∇CDM cosmology with a prior on H0 that encompasses the most recent direct measurements, we find S8 ≡σ8 √Ωm/0:3 = 0:745±0:039. This result is in good agreement with other low redshift probes of large scale structure, including recent cosmic shear results, along with pre-Planck cosmic microwave background constraints. A 2:3-σ tension in S8 and 'substantial discordance' in the full parameter space is found with respect to the Planck 2015 results. We use shear measurements for nearly 15 million galaxies, determined with a new improved 'self-calibrating' version of lensfit validated using an extensive suite of image simulations. Four-band ugri photometric redshifts are calibrated directly with deep spectroscopic surveys. The redshift calibration is confirmed using two independent techniques based on angular cross-correlations and the properties of the photometric redshift probability distributions. Our covariance matrix is determined using an analytical approach, verified numerically with large mock galaxy catalogues. We account for uncertainties in the modelling of intrinsic galaxy alignments and the impact of baryon feedback on the shape of the non-linear matter power spectrum, in addition to the small residual uncertainties in the shear and redshift calibration. The cosmology analysis was performed blind. Our high-level data products, including shear correlation functions, covariance matrices, redshift distributions, and Monte Carlo Markov Chains are available at http://kids.strw.leidenuniv.nl.

Original languageEnglish (US)
Pages (from-to)1-50
Number of pages50
JournalMonthly Notices of the Royal Astronomical Society
Volume465
Issue number2
StatePublished - Feb 2017
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Keywords

  • Cosmology: observations
  • Galaxies: photometry
  • Gravitational lensing: weak
  • Surveys

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