Characterization of LSST CCDs Using Realistic Images, Before First Light
arXiv:1808.00534 · doi:10.1117/12.2314276
Abstract
The 3.2 gigapixel LSST camera, an array of 189 thick fully-depleted CCDs, will repeatedly image the southern sky and accomplish a wide variety of science goals. However, its trove of tens of billions of object images implies stringent requirements on systematic biases imprinted during shift-and-stare CCD observation. In order to correct for these biases which, without correction, violate requirements on weak lensing precision, we investigate CCD systematics using both simulations of charge transport as well as with a unique bench-top optical system matched to the LSST's fast f/1.2 beam. By illuminating single CCDs with realistic scenes of stars and galaxies and then analyzing these images with the LSST data management pipelines, we can characterize the survey's imaging performance well before the camera's first light. We present measurements of several CCD systematics under varying conditions in the laboratory, including the brightness-dependent broadening of star and galaxy images, charge transport anomalies in the silicon bulk as well as the edges, and serial deferred charge. Alongside these measurements, we also present the development and testing of physics-based models which inform corrections or mitigation strategies for these systematics. Optimization of the CCD survey operation under a variety of realistic observational conditions, including systematic effects from the optics, clocking, sky brightness, and image analysis, will be critical to achieve the LSST's goals of precision astronomy and cosmology.
arXiv comment13 pages, 7 figures (all black & white)
References in corpus (15)
- LSST: from Science Drivers to Reference Design and Anticipated Data Products
- Shapes and Shears, Stars and Smears: Optimal Measurements for Weak Lensing
- The Third Gravitational Lensing Accuracy Testing (GREAT3) Challenge Handbook
- The brighter-fatter effect and pixel correlations in CCD sensors
- The LSST Data Management System
- Characterization and correction of charge-induced pixel shifts in DECam
- Photometry of supernovae in an image series : methods and application to the Supernova Legacy Survey (SNLS)
- Measurements and Simulations of the Brighter-Fatter Effect in CCD Sensors
- Precision Astronomy with Imperfect Fully Depleted CCDs -- An Introduction and a Suggested Lexicon
- LSST optical beam simulator
- A Binary Offset Effect in CCD Readout and Its Impact on Astronomical Data
- Is Flat Fielding Safe for Precision CCD Astronomy?
- Mapping charge transport effects in thick CCDs with a dithered array of 40,000 stars
- Charge Diffusion Variations in Pan-STARRS\,1 CCDs
- Spurious shear induced by the tree rings of the LSST CCDs