Cosmic Web Research with KAT-7, MeerKAT & FAST

TL;DR

This paper discusses the development and scientific potential of the KAT-7, MeerKAT, and FAST radio telescopes for cosmic web research, emphasizing their technical features and future combined capabilities.

Contribution

It presents the technical details, commissioning results, and future prospects of KAT-7 and MeerKAT for low-surface-brightness HI studies and cosmic web exploration.

Findings

KAT-7 successfully tested for large-scale HI emission detection.

MeerKAT construction progress and early science plans.

Future combination of FAST and MeerKAT data to explore low-density cosmic web regions.

Abstract

The seven-dish KAT-7 array was built as an engineering test-bed for the 64-dish Karoo Array Telescope, known as MeerKAT, which is the South African precursor of the Square Kilometre Array (SKA). KAT-7 and MeerKAT are located close to the South African SKA core site in the Northern Cape's Karoo desert region. Construction of the KAT-7 array was completed in December 2010. The short baselines (26 to 185 m) and low system temperature (T$_{\rm sys} \sim$ 26 K) of the telescope make it very sensitive to large-scale, low-surface-brightness emission, which is one of the HI science drivers for MeerKAT and one of the future strengths of FAST. While the main purpose of KAT-7 was to test technical solutions for MeerKAT and the SKA, scientific targets were also observed during commissioning to test the HI line mode and the first results obtained are presented. A description of MeerKAT and an update on its construction is also given. Early science should start in mid-2016 with a partial array and the full array should be completed at the end of 2017. For cosmic-web research (detection of low column density HI), a future combination of data from FAST and MeerKAT should allow to explore the unknown territory of $< 10^{18}$ cm$^{-2}$ surface densities and the possible connection between spiral galaxies and the surrounding cosmic web.