Linearity and correction of the BF effect in LSST sensors

Abstract

The Brighter-Fatter (hereafter BF) effect in CCD sensors causes increases in the image size of bright objects due to electrostatic repulsion of collected charges. Correcting this effect in the LSST camera is required in order to meet the science goals of the project, especially galaxy shape measurements for weak lensing. The current plan for BF image correction in the LSST is to use the deconvolution method described in Coulton, et.al. [1]. In this work, we study the linearity of the BF effect and effectiveness of the Coulton correction, using both simulation tools and measurements made on prototype LSST CCDs from both CCD vendors. We conclude that the proposed image correction method may be adequate to meet the LSST science goals, although more work is needed on the algorithms used to generate the image correction kernel from sensor measurements.