Looking ahead to the sky with the Square Kilometre Array: simulating flux densities and resolved radio morphologies of 0 < z < 2.5 star-forming galaxies.

SKA-MID surveys will be the first in the radio domain to achieve clearly sub-arcsecond resolution at high sensitivity over large areas, opening new science applications for galaxy evolution. To investigate the potential of these surveys, we create simulated SKA-MID images of a ∼0.04 deg² region of GOODS-North, constructed using multi-band HST imaging of 1723 real galaxies containing significant substructure at 0 < z < 2.5. We create images at the proposed depths of the band 2 wide, deep, and ultradeep reference surveys (RMS = 1.0, 0.2, and 0.05 μJy over 1000, 10–30, and 1 deg², respectively), using the telescope response of SKA-MID at 0.6 arcsec resolution. We quantify the star formation rate – stellar mass space the surveys will probe, and asses to which stellar masses the surveys will be complete. We measure galaxy flux density, half-light radius (R ₅₀), concentration, Gini (distribution of flux), second-order moment of the brightest pixels (M ₂₀), and asymmetry before and after simulation with the SKA response, to perform input-output tests as a function of depth, separating the effects of convolution and noise. We find that the recovery of Gini and asymmetry is more dependent on survey depth than for R ₅₀, concentration and M ₂₀. We also assess the relative ranking of parameters before and after observation with SKA-MID. R ₅₀ best retains its ranking, while asymmetries are poorly recovered. We confirm that the wide tier will be suited to the study of highly star-forming galaxies across different environments, whilst the ultradeep tier will enable detailed morphological analysis to lower SFRs. [ABSTRACT FROM AUTHOR]