Euclid: Improving the efficiency of weak lensing shear bias calibration. Pixel noise cancellation and the response method on trial
Abstract
To obtain an accurate cosmological inference from upcoming weak lensing surveys such as the one conducted by Euclid, the shear measurement requires calibration using galaxy image simulations. We study the efficiency of different noise cancellation methods that aim at reducing the simulation volume required to reach a given precision in the shear measurement. Explicitly, we compared fit methods with different noise cancellations and a method based on responses. We used GalSim to simulate galaxies both on a grid and at random positions in larger scenes. Placing the galaxies at random positions requires their detection, which we performed with SExtractor. On the grid, we neglected the detection step and, therefore, the potential detection bias arising from it. The shear of the simulated images was measured with the fast moment-based method KSB, for which we note deviations from purely linear shear measurement biases. For the estimation of uncertainties, we used bootstrapping as an empirical method. We find that each method we studied on top of shape noise cancellation can further increase the efficiency of calibration simulations. The improvement depends on the considered shear amplitude range and the type of simulations (grid-based or random positions). The response method on a grid for small shears provides the biggest improvement. In the more realistic case of randomly positioned galaxies, we still find an improvement factor of 70 for small shears using the response method. Alternatively, the runtime can be lowered by a factor of 7 already using pixel noise cancellation on top of shape noise cancellation. Furthermore, we demonstrate that the efficiency of shape noise cancellation can be enhanced in the presence of blending if entire scenes are rotated instead of individual galaxies.
Keywords
Cite
@article{arxiv.2401.08239,
title = {Euclid: Improving the efficiency of weak lensing shear bias calibration. Pixel noise cancellation and the response method on trial},
author = {H. Jansen and M. Tewes and T. Schrabback and N. Aghanim and A. Amara and S. Andreon and N. Auricchio and M. Baldi and E. Branchini and M. Brescia and J. Brinchmann and S. Camera and V. Capobianco and C. Carbone and V. F. Cardone and J. Carretero and S. Casas and M. Castellano and S. Cavuoti and A. Cimatti and G. Congedo and L. Conversi and Y. Copin and L. Corcione and F. Courbin and H. M. Courtois and A. Da Silva and H. Degaudenzi and J. Dinis and F. Dubath and X. Dupac and M. Farina and S. Farrens and S. Ferriol and M. Frailis and E. Franceschi and M. Fumana and S. Galeotta and B. Gillis and C. Giocoli and A. Grazian and F. Grupp and S. V. H. Haugan and H. Hoekstra and W. Holmes and F. Hormuth and A. Hornstrup and P. Hudelot and K. Jahnke and B. Joachimi and S. Kermiche and A. Kiessling and M. Kilbinger and T. Kitching and B. Kubik and H. Kurki-Suonio and S. Ligori and P. B. Lilje and V. Lindholm and I. Lloro and E. Maiorano and O. Mansutti and O. Marggraf and K. Markovic and N. Martinet and F. Marulli and R. Massey and E. Medinaceli and S. Mei and M. Melchior and Y. Mellier and M. Meneghetti and E. Merlin and G. Meylan and L. Miller and M. Moresco and L. Moscardini and E. Munari and R. Nakajima and S. -M. Niemi and C. Padilla and S. Paltani and F. Pasian and K. Pedersen and V. Pettorino and S. Pires and G. Polenta and M. Poncet and F. Raison and A. Renzi and J. Rhodes and G. Riccio and E. Romelli and M. Roncarelli and E. Rossetti and R. Saglia and D. Sapone and B. Sartoris and P. Schneider and A. Secroun and G. Seidel and S. Serrano and C. Sirignano and G. Sirri and J. Skottfelt and L. Stanco and P. Tallada-Crespí and I. Tereno and R. Toledo-Moreo and F. Torradeflot and I. Tutusaus and E. A. Valentijn and L. Valenziano and T. Vassallo and A. Veropalumbo and Y. Wang and J. Weller and G. Zamorani and J. Zoubian and C. Colodro-Conde and V. Scottez},
journal= {arXiv preprint arXiv:2401.08239},
year = {2024}
}
Comments
Accepted by A&A. 24 pages, 15+7 figures, Euclid standard paper