Euclid, Vera Rubin Observatory, WFIRST Joint Survey Processing: The Whole is Greater Than the Sum of Its Parts

Abstract

The Euclid, Vera Rubin Observatory and WFIRST projects will undertake flagship optical / near-infrared surveys in the 2020s. They will map thousands of square degrees of sky and cover the electromagnetic spectrum between 0.3 and 2.0 microns with sub-arcsecond resolution. Joint survey processing (JSP) is the pixel level combination of the Vera Rubin Observatory, Euclid, and WFIRST datasets. By combining the high spatial resolution of the space-based datasets with deep, seeing-limited, ground-based images in the optical bands, and accounting for color- and position-dependent point spread functions, systematics like source confusion, shape determination and astrometric mismatch can be addressed. This would yield the highest precision optical/infrared photometric and shear catalogs which enables a range of time-domain, cosmological, and astrophysical science by the community. The science investigations that benefit from JSP range from, solving for asteroid trajectories and composition, to the most precise constraints on the nature of dark energy and the expansion rate of the Universe. We discuss the science drivers for optimal handling of the ≈100 Petabytes of reduced data from Euclid, the Vera Rubin Observatory, and WFIRST, and the computational and networking infrastructure needed to enable distributed co-processing of these datasets. JSP can result in a factor of ≈3 reduction in photometric uncertainty at ≈26 AB mag, after all astrometric errors and deblending are corrected for, and reduce photometric biases by ≈20–100% depending on the flux density level.