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arXiv · 1303.1808

CFHTLenS tomographic weak lensing cosmological parameter constraints: Mitigating the impact of intrinsic galaxy alignments

Catherine Heymans·Emma Grocutt·Alan Heavens·Martin Kilbinger·Thomas D. Kitching·Fergus Simpson·Jonathan Benjamin·Thomas Erben·Hendrik Hildebrandt·Henk Hoekstra·Yannick Mellier·Lance Miller·Ludovic Van Waerbeke·Michael L. Brown·Jean Coupon·Liping Fu·Joachim Harnois-Deraps·Michael J. Hudson·Konrad Kuijken·Barnaby Rowe·Tim Schrabback·Elisabetta Semboloni·Sanaz Vafaei·Malin Velander
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Abstract

We present a finely-binned tomographic weak lensing analysis of the Canada-France-Hawaii Telescope Lensing Survey, CFHTLenS, mitigating contamination to the signal from the presence of intrinsic galaxy alignments via the simultaneous fit of a cosmological model and an intrinsic alignment model. CFHTLenS spans 154 square degrees in five optical bands, with accurate shear and photometric redshifts for a galaxy sample with a median redshift of zm =0.70. We estimate the 21 sets of cosmic shear correlation functions associated with six redshift bins, each spanning the angular range of 1.5<theta<35 arcmin. We combine this CFHTLenS data with auxiliary cosmological probes: the cosmic microwave background with data from WMAP7, baryon acoustic oscillations with data from BOSS, and a prior on the Hubble constant from the HST distance ladder. This leads to constraints on the normalisation of the matter power spectrum sigma_8 = 0.799 +/- 0.015 and the matter density parameter Omega_m = 0.271 +/- 0.010 for a flat Lambda CDM cosmology. For a flat wCDM cosmology we constrain the dark energy equation of state parameter w = -1.02 +/- 0.09. We also provide constraints for curved Lambda CDM and wCDM cosmologies. We find the intrinsic alignment contamination to be galaxy-type dependent with a significant intrinsic alignment signal found for early-type galaxies, in contrast to the late-type galaxy sample for which the intrinsic alignment signal is found to be consistent with zero.

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Catherine Heymans, Emma Grocutt, Alan Heavens, Martin Kilbinger, Thomas D. Kitching, Fergus Simpson, Jonathan Benjamin, Thomas Erben, Hendrik Hildebrandt, Henk Hoekstra, Yannick Mellier, Lance Miller, Ludovic Van Waerbeke, Michael L. Brown, Jean Coupon, Liping Fu, Joachim Harnois-Deraps, Michael J. Hudson, Konrad Kuijken, Barnaby Rowe, Tim Schrabback, Elisabetta Semboloni, Sanaz Vafaei, Malin Velander. 2013-03-07. CFHTLenS tomographic weak lensing cosmological parameter constraints: Mitigating the impact of intrinsic galaxy alignments. https://doi.org/10.1093/mnras/stt601

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