Square Kilometre Array Science Data Challenge 3a: foreground removal for an EoR experiment

Abstract

We present and analyse the results of the Science Data Challenge 3a (SDC3a, https://sdc3.skao.int/challenges/foregrounds), an epoch of reionization (EoR) foreground removal exercise organized by the Square Kilometre Array Observatory (SKAO) on SKA simulated data. The challenge ran for 8 months, from 2023 March to October. Participants were provided with realistic simulations of SKA-Low data between 106 and 196 MHz, including foreground contamination from extragalactic and Galactic emission, instrumental, and systematic effects. The challenge results provide a means for all teams to understand and improve their performance. This challenge indicates that the comparison between independent pipelines could be a powerful tool to assess residual biases and improve error estimation.