Equatorial Imaging with e-MERLIN Including the Chilbolton Antenna

TL;DR

Adding the Chilbolton antenna to e-MERLIN significantly improves equatorial imaging by enhancing beam shape and survey efficiency, crucial for upcoming southern hemisphere astronomical observations.

Contribution

This paper demonstrates how including the Chilbolton dish enhances e-MERLIN's equatorial imaging capabilities and beam quality, a novel approach for array configuration.

Findings

Improved beam shape with more circular and compact profile.

Reduced sidelobe structure in the array's beam.

Enhanced survey efficiency for equatorial sky regions.

Abstract

We discuss the equatorial imaging benefits that arise from the addition of the 25-metre dish at Chilbolton to the e-MERLIN array. Its inclusion considerably enhances the capabilities of e-MERLIN on and below the equator. This will become particularly important in the era of ALMA and other upcoming southern hemisphere facilities. We present simulated observations of point sources in the equatorial region of the sky which is the target area for many existing sky surveys. We find that the additional baselines created by the inclusion of the Chilbolton dish favourably adjust the beam shape of e-MERLIN to a more compact and circular shape, with significantly reduced sidelobe structure. Putting aside the benefits of increased collecting area, the modified beam shape has implications for more rapidly reaching a given completeness limit for equatorial surveys.