CFHT UM2019 - Presentation Details

Abstract Details

Title: ShapePipe, a shear measurement pipeline in the CFIS context

Presenter: Axel Guinot


The Canada-France Imaging Survey (CFIS) is an ongoing wide-field imaging survey. It will cover around 5000 deg2 in the u- and r-band on the Northern hemisphere with excellent image quality (median r-band seeing 0.65 arcsec). The recently formed collaboration with Pan-STARRS (UNIONS: Ultraviolet Near-Infrared Optical Northern Survey) is adding deep i- and z-band observations for photometric redshifts. These characteristics makes this survey extremely interesting for weak-lensing analyses. In this framework we are developing a new, modular galaxy shape measurement pipeline, ShapePipe, incorporating state-of-the-art techniques for object and blended galaxy detection, shape measurement, shear calibration, and validation diagnostics. I will present the first version of ShapePipe, and show preliminary weak-lensing results of CFIS analysis over the CFHTLenS W3 area. Our galaxy shear estimates analysis have been calibration with a recent method called metacalibration), which does not require image simulations but derives the shear calibration from the data themselves. Further, I will present a clustering-based redshift method as an alternative to photo-z. In light of limited color information but overlap with deep spectroscopic surveys such as BOSS and eBOSS, we plan to apply this method to CFIS/UNIONS to obtain redshift information for the lensed galaxies. I will show preliminary results of this method on simulations.