Title: Recent Progress in Weak Lensing Measurement   

Place: The Lecture Hall, 3rd floor in Astronomy Building (天文大厦报告厅)   

Date & Time: 15:00 on Oct. 27th (Thursday)   

Speaker: Jun Zhang, CAA/SJTU) 

Abstract:   

Weak lensing is an important probe of the cosmic structure and the scale evolution of our Universe. We show that the weak lensing effect (also called cosmic shear) can be measured accurately from background galaxy images through Fourier transformation in the presence of background noise, source Poisson noise, and finite pixel size, without assumptions on the morphologies of galaxy and PSF. More recently, we have further optimized the way of taking the ensemble average of the cosmic shear signal, and the way of measuring the point-spread-function at the positions of the galaxies. We show some preliminary measurement results using the CFHTlens data, and demonstrate that our method is the most promising technique for cosmic shear measurement in the ongoing and upcoming large scale galaxy surveys.