Simple Treatments of the Photon Noise and the Pixelation Effect in Weak Lensing - Astrophysics > Cosmology and Nongalactic AstrophysicsReportar como inadecuado




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Abstract: We propose easy ways of correcting for the systematic errors caused by thephoton noise and the pixelation effect in cosmic shear measurements. Ourtreatment of noise can reliably remove the noise contamination to the cosmicshear even when the flux density of the noise is comparable with those of thesources. For pixelated images, we find that one can accurately reconstructtheir corresponding continuous images by interpolating the logarithms of thepixel readouts with either the Bicubic or the Bicubic Spline method. The cosmicshears measured from the interpolated continuous images contain negligiblesystematic errors as long as the pixel size is about less than the scale sizeof the point spread function PSF, including the pixel response function, acondition which is almost always satisfied in practice. Our methodology is welldefined regardless of the morphologies of the galaxies and the PSF. Despitethat our discussion is based on the shear measurement method of Zhang 2008,our way of treating the noise can in principle be considered in other methods,and the interpolation method that we introduce for reconstructing continuousimages from pixelated ones is generally useful for digital image processing ofall purposes.



Autor: Jun Zhang UC Berkeley, UT Austin

Fuente: https://arxiv.org/







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