Efficient Optimal Image Reconstruction for the Nancy Grace Roman Space Telescope and Beyond: I. First Results with {\sc Effortless}

Abstract

The forthcoming Nancy Grace Roman Space Telescope will revolutionize astrophysics by generating huge amounts of data of unprecedented quality. To properly address the data deluge and fully realize its potential, analysis tools that are both efficient and optimal are needed. {\sc Effortless} (previously known as Fast {\sc Imcom}) is a new algorithm for linear image reconstruction. Like its predecessor {\sc Imcom}, it offers control over point spread functions in output images; by avoiding laborious calculations, it is tens of times faster and has a smaller memory footprint. In this paper, I apply {\sc Effortless} to simulated Roman images and present promising first results. With ideal point sources, I illustrate that a single image reconstructed by {\sc Effortless}, combined with the post-measurement calibration procedure described in a companion paper, can lead to better measurements than a set of $\sim 6$ images coadded by {\sc Imcom}. While both algorithms were originally designed for weak gravitational lensing cosmology, {\sc Effortless} can benefit studies of static features and dynamic aspects of the Universe alike. Moreover, the efficiency and interpretability of {\sc Effortless} provides new possibilities for further reducing errors in measurements. The implementation of {\sc Effortless} is detailed in the companion paper.