Sub-millimetre Galaxies with Webb Near-infrared Counterparts and Multi-Wavelength Morphology

We utilised the unprecedented depth and resolution of recent early-release science (ERS) JWST observations to define the near-infrared counterparts of sub-millimetre galaxies (SMGs). We identified 45 SCUBA-2 SMG positions within the Cosmic Evolution Early Release Science (CEERS) survey JWST/NIRCam fields. Through an analysis of multi-wavelength p-values, NIRCam colours and predicted SCUBA-2 fluxes, we define 43 JWST/NIRCam counterparts to the SCUBA-2 SMGs, finding a 63 per cent agreement with those identified in prior HST studies. Using EaZy-py, we fitted the available HST and JWST observations to quantify the photometric redshifts of the NIRCam-SMGs, establishing a broad range of redshift from z & AP; 0.2-5.4 with a median of z & AP; 2.29, in agreement with other studies of SMGs. We identified significant variations in the morphology of the NIRCam-SMGs from isolated discs and spheroidal galaxies to irregular interacting systems. We analysed their rest-frame optical and near-infrared morphological properties (e.g. effective radius (R-e), Sersic index (n), concentration (C), asymmetry (A), clumpiness (S), as well as the Gini and M-20 parameters), finding, on average, late-type disc-like morphologies with large scatter into the intermediate and merger regions of the non-parametric parameter space. For the non-merging galaxies, we find a median rest-frame optical size and Sersic index (and 1 & sigma; scatter) of R-e = 3.10 & PLUSMN; 1.67 kpc and n = 0.96 & PLUSMN; 0.66. Whilst in the rest-frame near-infrared, we establish more compact, higher Sersic index morphologies (R-e = 1.64 & PLUSMN; 0.97, n = 1.85 & PLUSMN; 0.63). We further establish that both the rest-frame optical and near-infrared effective radii correlate negatively (at a 2 & sigma; level) with redshift, whilst the Sersic index remains constant with cosmic time. Our results are consistent with the picture of inside-out galaxy evolution, with more centrally concentrated older stellar populations, and more extended, younger star-forming regions whose stellar emission is heavily attenuated in the central regions.