Volume 656, December 2021
|Number of page(s)||10|
|Section||Cosmology (including clusters of galaxies)|
|Published online||15 December 2021|
A fully data-driven algorithm for accurate shear estimation
Leiden Observatory, Leiden University, PO Box 9513 2300 RA Leiden, The Netherlands
Accepted: 13 September 2021
Weak lensing by large-scale structure is a powerful probe of cosmology if the apparent alignments in the shapes of distant galaxies can be accurately measured. We study the performance of a fully data-driven approach, based on METADETECTION, focusing on the more realistic case of observations with an anisotropic point spread function (PSF). Under the assumption that PSF anisotropy is the only source of additive shear bias, we show how unbiased shear estimates can be obtained from the observed data alone. To do so, we exploit the finding that the multiplicative shear bias obtained with METADETECTION is nearly insensitive to the PSF ellipticity. In practice, this assumption can be validated by comparing the empirical corrections obtained from observations to those from simulated data. We show that our data-driven approach meets the stringent requirements for upcoming space- and ground-based surveys, although further optimisation is possible.
Key words: gravitational lensing: weak / cosmology: observations
© ESO 2021
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