Improving PSF modelling for weak gravitational lensing using new methods in model selection - Astrophysics > Cosmology and Nongalactic AstrophysicsReport as inadecuate




Improving PSF modelling for weak gravitational lensing using new methods in model selection - Astrophysics > Cosmology and Nongalactic Astrophysics - Download this document for free, or read online. Document in PDF available to download.

Abstract: A simple theoretical framework for the description and interpretation ofspatially correlated modelling residuals is presented, and the resulting toolsare found to provide a useful aid to model selection in the context of weakgravitational lensing. The description is focused upon the specific problem ofmodelling the spatial variation of a telescope point spread function PSFacross the instrument field of view, a crucial stage in lensing data analysis,but the technique may be used to rank competing models wherever data aredescribed empirically. As such it may, with further development, provide usefulextra information when used in combination with existing model selectiontechniques such as the Akaike and Bayesian Information Criteria, or theBayesian evidence. Two independent diagnostic correlation functions aredescribed and the interpretation of these functions demonstrated using asimulated PSF anisotropy field. The efficacy of these diagnostic functions asan aid to the correct choice of empirical model is then demonstrated byanalyzing results for a suite of Monte Carlo simulations of random PSF fieldswith varying degrees of spatial structure, and it is shown how the diagnosticfunctions can be related to requirements for precision cosmic shearmeasurement. The limitations of the technique, and opportunities forimprovements and applications to fields other than weak gravitational lensing,are discussed.



Author: Barnaby Rowe

Source: https://arxiv.org/



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