Observing the Dark Universe with the Canada- France Hawaii Telescope Lensing Survey Catherine Heymans Institute for Astronomy, University of Edinburgh
The intervening dark matter lenses the light from distant galaxies. Weak Gravitational Lensing
Before lensing galaxies are randomly oriented*
Weak Gravitational Lensing Dark Matter Galaxies Lensed galaxies align
Clowe/Bradac et al
LSST forecast Ivezic et al 2011
CFHTLenS Survey Statistics 155 sq degrees, ugriz to i<24.7 (CFHTLS) High resolution: 17 gals per sq arcmin Deep imaging: zm = 0.75 Accurate redshifts: σz= 0.04(1+z) with 4% outliers Accurate shear: <m> = - 0.06 <c> = 0.001 Robust to systematic errors: 75% of the data used
The CFHT Lensing Survey UBC L. Van Waerbeke (PI) J. Benjamin H.Hildebrandt M. Milkeraitis S.Vafaei Edinburgh C. Heymans (PI) T. Kitching E. Grocutt A. Heavens F. Simpson Bonn T. Erben P. Simon T. Schrabback K. Holhjem Leiden H. Hoekstra K. Kuijken E. Semboloni E. van Uitert M. Smit Oxford L. Miller M. Velander IAP Y. Mellier R. Gavazzi Munich M. Kilbinger Waterloo M Hudson B. Gillis CSIC/IEEC C. Bonnett Shanghai L. Fu Tohoku J. Coupon UCL/JPL B. Rowe
Dark Matter changes the shapes of galaxies by ~1% Telescopes and the Atmosphere change the shapes of galaxies by ~15% Kitching et al 2010 We need to understand our instrumentation, modelling and analysis techniques to very high precision
Multi-epoch vs stacked data Slide from Henk Hoekstra
Kilbinger et al 2013
How aligned the galaxy pairs are Galaxy pair separation Kilbinger et al 2013
Fu et al 2008: Stack analysis Kilbinger et al 2013: Multi-epoch analysis Signal Signal Systematics Systematics θ (arcmin) θ (arcmin)
Galaxy-Galaxy Cosmology insensitive test of redshift-scaling 2.0 10-3 1.5 10-3 [0.2,0.4] [0.4,0.5] [0.5,0.7] [0.7,0.9] [0.9,1.3] <! t > at "=1 arcmin 1.0 10-3 5.0 10-4 0.0 10 0 Heymans et al 2012 0.14 0.29 0.44 0.61 0.79 1.06 mean photometric redshift sources
Cosmic Shear Cosmology sensitive measure of redshift-scaling How aligned the galaxy pairs are Heymans et al 2013
Flat LCDM Heymans et al 2013 ij + ( )= dk k J 0 (k ) Survey depth dw G i (w) G j (w) P Non-linear PS (Ωm ΩΔ σ8 w Η0..) k f k (w),w
Beyond-Einstein gravity theories ds 2 = (1 + 2 )dt 2 + a 2 (t)(1 + 2 )dx 2 Dynamical Potential Space Curvature Potential Poissons Equation 2 =4 Ga 2 GR fully tested on solar system scales, so any modification must be length or time dependent
Beyond-Einstein gravity theories ds 2 = (1 + 2 )dt 2 + a 2 (t)(1 + 2 )dx 2 Dynamical Potential Space Curvature Potential 2 ] =4 Ga 2 [1 + µ(a)] 2 [ + ] =8 Ga 2 [1 + (a)]
10 4 GR µ 0 = 0.5 Σ 0 = 0.5 CFHTLenS: relativistic ξ ± ( θ) 10 5 10 6 LOW-LOW LOW-HIGH HIGH-HIGH 10 0 10 1 θ (arcmin) 0.9 0.8 0.7 0.6 10 0 10 1 θ (arcmin) RSD: non-relativistic 10 0 10 1 GR µ 0 = 0.5 µ 0 = 1 Simpson et al 2013 & Benjamin et al 2013 θ (arcmin) f σ 8 0.5 0.4 0.3 0.2 0.1 D WiggleZ - Blake et al 2012 & 6dfGRS Beutler et al 2012 0 0 0.2 0.4 0.6 0.8 1 1.2 z
Simpson, Heymans et al 2013
Atmospheric effects Heymans/Rowe et al 2012
Atmospheric effects Heymans/Rowe et al 2012 Chang et al 2012
LSST Simulation Chang et al 2012 CFHT short exposure Data Heymans et al 2012
Calibration dependent on both Resolution and SNR true =(1+m) obs
CFHTLenS Data release: Download now from www.cfhtlens.org: 155 sq degrees ugriz lensing quality reduced deep pixel data Combined Lensing Shear and Photometric redshift catalogues to i<24.7 Tomographic shear correlation functions, redshift distributions and covariance matrices MCMC chains available on request
Technical Heymans et al. 2012 "CFHTLenS: The Canada- France-Hawaii Telescope Lensing Survey" Erben et al. 2013 "CFHTLenS: The Canada-France- Hawaii Telescope Lensing Survey - Imaging Data and Catalogue Products" Miller et al. 2013 "Bayesian Galaxy Shape Measurement for Weak Lensing Surveys -III. Application to CFHTLenS" Hildebrandt et al. 2012 "CFHTLenS: improving the quality of photometric redshifts with precision photometry" Heymans & Rowe et al. 2012 "The impact of high spatial frequency atmospheric distortions on weaklensing measurements" Cosmology Kilbinger et al. 2013 "CFHTLenS: Combined Probe Cosmological Model Comparison using 2D Weak Gravitational Lensing" Simpson et al. 2013 "CFHTLenS: Testing the Laws of Gravity with Tomographic Weak Lensing and Redshift Space Distortions" Benjamin et al. 2013 "CFHTLenS tomographic weak lensing: Quantifying accurate redshift distributions" Heymans et al. 2013 "CFHTLenS tomographic weak lensing cosmological parameter constraints: Mitigating the impact of intrinsic galaxy alignments" Van Waerbeke et al. 2013 "CFHTLenS: Mapping the Large Scale Structures" Galaxy-galaxy Lensing Gillis et al. 2013 "CFHTLenS: The Environmental Dependence of Galaxy Halo Masses from Weak Lensing" Simon et al. 2013 "CFHTLenS: Higher-order galaxy-mass correlations probed by galaxy-galaxy-galaxy lensing" Velander et al. 2013 "CFHTLenS: The Relation Between Galaxy Dark Matter Haloes and Baryons from Weak Gravitational Lensing"
alternative slides!
m Planck
How intrinsically aligned the galaxy pairs are Heymans et al 2013
How aligned the galaxy pairs are Galaxy pair separation
low z, high z high z, high z How aligned the galaxy pairs are low z, low z Galaxy pair separation
CFHTLenS The state-of-the-art cosmological survey with 155 sq degrees, ugriz to i<24.7 (7σ extended source) Uses 5 yrs of data from the Deep, Wide and Pre-survey components of the CFHT Legacy Survey
GAMA-II VVDS Deep 64 sq degrees 22.5 sq degrees CFHTLS : 155 sq degrees 44 sq degrees 23 sq degrees VIPERS DEEP2 ugriz, to i=24.7 VVDS Wide Coupon et al 2010
Simpson, Heymans et al 2013 (a) µ(a) =µ 0 (a) = 0 (a)
Flat wcdm Curved wcdm Heymans et al 2013