CFHTLenS: combined probe cosmological model comparison using 2D weak gravitational lensing

Martin Kilbinger, Liping Fu, Catherine Heymans, Fergus Simpson, Jonathan Benjamin, Thomas Erben, Joachim Harnois-Deraps, Henk Hoekstra, Hendrik Hildebrandt, Thomas D. Kitching, Yannick Mellier, Lance Miller, Ludovic Van Waerbeke, Karim Benabed, Christopher Bonnett, Jean Coupon, Michael J. Hudson, Konrad Kuijken, Barnaby Rowe, Tim SchrabbackElisabetta Semboloni, Sanaz Vafaei, Malin Velander

Research output: Contribution to journalArticlepeer-review

Abstract

We present cosmological constraints from 2D weak gravitational lensing by the large-scale structure in the Canada-France-Hawaii Telescope Lensing Survey (CFHTLenS) which spans 154 deg(2) in five optical bands. Using accurate photometric redshifts and measured shapes for 4.2 million galaxies between redshifts of 0.2 and 1.3, we compute the 2D cosmic shear correlation function over angular scales ranging between 0.8 and 350 arcmin. Using non-linear models of the dark-matter power spectrum, we constrain cosmological parameters by exploring the parameter space with Population Monte Carlo sampling. The best constraints from lensing alone are obtained for the small-scale density-fluctuations amplitude sigma(8) scaled with the total matter density Omega(m). For a flat Lambda cold dark matter (Lambda CDM) model we obtain sigma(8)(Omega(m)/0.27)(0.6) = 0.79 +/- 0.03.

We combine the CFHTLenS data with 7-year Wilkinson Microwave Anisotropy Probe (WMAP7), baryonic acoustic oscillations (BAO): SDSS-III (BOSS) and a Hubble Space Telescope distance-ladder prior on the Hubble constant to get joint constraints. For a flat Lambda CDM model, we find Omega(m) = 0.283 +/- 0.010 and sigma(8) = 0.813 +/- 0.014. In the case of a curved wCDM universe, we obtain Omega(m) = 0.27 +/- 0.03, sigma(8) = 0.83 +/- 0.04, w(0) = -1.10 +/- 0.15 and Omega(K) = 0.006(-0.004)(+0.006).

We calculate the Bayesian evidence to compare flat and curved Lambda CDM and dark-energy CDM models. From the combination of all four probes, we find models with curvature to be at moderately disfavoured with respect to the flat case. A simple dark-energy model is indistinguishable from Lambda CDM. Our results therefore do not necessitate any deviations from the standard cosmological model.

Original languageEnglish
Pages (from-to)2200-2220
Number of pages21
JournalMonthly Notices of the Royal Astronomical Society
Volume430
Issue number3
DOIs
Publication statusPublished - Apr 2013

Keywords

  • methods: statistical
  • cosmological parameters
  • MATTER POWER SPECTRUM
  • SHEAR CORRELATION-FUNCTIONS
  • DARK-ENERGY CONSTRAINTS
  • POPULATION MONTE-CARLO
  • HUBBLE-SPACE-TELESCOPE
  • COSMIC SHEAR
  • PHOTOMETRIC REDSHIFTS
  • COVARIANCE-MATRIX
  • LEGACY SURVEY
  • INTRINSIC ALIGNMENTS

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