The CFHT Lensing Survey

Welcome to the Astronomer section of the website for the Canada-France Hawaii Telescope Lensing Survey: CFHTLenS.

Access CFHTLenS Shear and Photometric Redshift catalogues here

CFHTLenS is a 154 square degree multi-colour optical survey in ugriz incorporating all five years worth of data from the Wide, Deep and Pre-survey components on the CFHT Legacy Survey. The CFHTLS was optimised for weak lensing analysis with the deep i-band data taken in optimal sub-arcsecond seeing conditions. For a general overview of the survey see Erben et al 2012 and Heymans et al 2012

The survey has:

High resolution imaging with 17 resolved galaxies per sq arcmin
Deep multi-colour data with a median redshift of 0.75
Accurate photometry resulting in a photometric redshift scatter of 0.04(1+z) and 4% catastrophic outlier rate
Accurate calibrated shear measurement

The CFHTLenS team have developed four new data analysis methods to enable a robust and accurate weak lensing analysis of the data:

Lensing quality data reduction with THELI detailed in Erben et al 2012
Bayesian model-fitting for shear measurement with Lensfit outlined in Miller et al 2012
Gaussianised Photometry for accurate photometric redshifts, detailed in Hildebrandt et al 2012
Robust field selection based on systematic error analyses, detailed in Heymans et al 2012

Download CFHTLenS data products from here.

For more information about the Dark Universe and Gravitational Lensing please visit the public side of the website.