Very High Angular Resolution Science with the Square Kilometre Array

TL;DR

The paper discusses the capabilities of the Square Kilometre Array (SKA) in achieving very high angular resolution, enabling new astrophysical discoveries across multiple fields through long baseline interferometry.

Contribution

It provides a comprehensive overview of the high angular resolution science enabled by the SKA and evaluates the scientific benefits of incorporating baselines over 1000 km.

Findings

SKA will achieve 40-2 mas resolution at 0.5-10 GHz.

Image sensitivity will reach <50 nJy/beam in 8 hours.

High angular resolution will enable detection of brightness temperatures <200 K.

Abstract

Preliminary specifications for the Square Kilometre Array (SKA) call for 25% of the total collecting area of the dish array to be located at distances greater than 180 km from the core, with a maximum baseline of at least 3000 km. The array will provide angular resolution ~ 40 - 2 mas at 0.5 - 10 GHz with image sensitivity reaching < 50 nJy/beam in an 8 hour integration with 500 MHz bandwidth. Given these specifications, the high angular resolution component of the SKA will be capable of detecting brightness temperatures < 200 K with milliarcsecond-scale angular resolution. The aim of this article is to bring together in one place a discussion of the broad range of new and important high angular resolution science that will be enabled by the SKA, and in doing so, address the merits of long baselines as part of the SKA. We highlight the fact that high angular resolution requiring baselines greater than 1000 km provides a rich science case with projects from many areas of astrophysics, including important contributions to key SKA science.