An overview of the completed Canada-France-Hawaii Telescope Lensing Survey (CFHTLenS)

TL;DR

The paper reviews the CFHTLenS survey, highlighting its technical challenges, solutions, and scientific achievements in weak lensing, and emphasizes its role as a standard-setting, publicly available dataset for cosmological research.

Contribution

It provides a comprehensive overview of the data analysis techniques, systematic effect treatments, and scientific results from the CFHTLenS survey, establishing a benchmark for future weak lensing studies.

Findings

Successful cosmic shear tomography analysis

Constraints on modified gravity models

Mapping of dark matter structures at large scales

Abstract

The Canada-France-Hawaii Telescope Legacy Survey (CFHTLS) represents the most powerful weak lensing survey carried out to date. The CFHTLenS (Canada-France-Hawaii Telescope Lensing Survey) team was formed in 2008 to analyse the data from the CFHTLS focussing on a rigorous treatment of systematic effects in shape measurements and photometric redshifts. Here we review the technical challenges that we faced in analysing these data and their solutions which set the current standard for weak lensing analyses. We also present some science highlights that were made possible by this effort including cosmic shear tomography, tests for modified gravity models, and the mapping of dark matter structures over unprecedentedly large scales. An outlook is given on current and future surveys that are analysed with the tools prepared for CFHTLenS. CFHTLenS represents the first and only weak lensing data set that has been made publicly available so far. We encourage other surveys to follow this example.