SuperCLASS -- I. The Super CLuster Assisted Shear Survey: Project
  overview and Data Release 1
  The SuperCLuster Assisted Shear Survey (SuperCLASS) is a legacy programme
using the e-MERLIN interferometric array. The aim is to observe the sky at
L-band (1.4 GHz) to a r.m.s. of 7 uJy per beam over an area of ~1 square degree
centred on the Abell 981 supercluster. The main scientific objectives of the
project are: (i) to detect the effects of weak lensing in the radio in
preparation for similar measurements with the Square Kilometre Array (SKA);
(ii) an extinction free census of star formation and AGN activity out to z~1.
In this paper we give an overview of the project including the science goals
and multi-wavelength coverage before presenting the first data release. We have
analysed around 400 hours of e-MERLIN data allowing us to create a Data Release
1 (DR1) mosaic of ~0.26 square degrees to the full depth. These observations
have been supplemented with complementary radio observations from the Karl G.
Jansky Very Large Array (VLA) and optical/near infra-red observations taken
with the Subaru, Canada-France-Hawaii and Spitzer Telescopes. The main data
product is a catalogue of 887 sources detected by the VLA, of which 395 are
detected by e-MERLIN and 197 of these are resolved. We have investigated the
size, flux and spectral index properties of these sources finding them
compatible with previous studies. Preliminary photometric redshifts, and an
assessment of galaxy shapes measured in the radio data, combined with a
radio-optical cross-correlation technique probing cosmic shear in a
supercluster environment, are presented in companion papers.
