Probing the Infrared/Radio correlation of the full IRAS Revised Bright Galaxy Sample with MeerKAT and the VLA

We study the infrared/radio correlation of galaxies in the IRAS Revised Bright Galaxy Sample using new MeerKAT observations at ν = 1.28\, GHz, complemented with VLA data. We classify the objects by primary energy source (Active Galactic Nuclei vs. Star-Forming) and take into account their merger status. With this, we aim to explore the effect of galaxy-galaxy interaction on the total-infrared (TIR)/radio correlation (qTIR) of star-forming galaxies by comparing the qTIR distribution between isolated and interacting/merging sources. We found the median qTIR to be 2.61 ± 0.01 (scatter = 0.16) for isolated galaxies and 2.51 ± 0.08 (scatter = 0.26) for interacting/merging galaxies. Our analysis reveals that interacting/merging galaxies exhibit lower qTIR and higher dispersion compared to isolated galaxies, and the difference is marginally significant. Interacting/merging galaxies have redder W2 − W3 colours, higher star formation rates (SFR) and specific SFR compared to isolated objects. We observe a significant decrease in qTIR with increasing radio luminosity for isolated galaxies. Additionally, we find the median ratio of TIR (8 μm < λ < 1000 μm) to far-infrared (FIR; 40 μm < λ < 120 μm) luminosities to be <LTIR/LFIR > ≈2.29. By examining the relation between LTIR and the mid-infrared (MIR) star-formation rate indicator (L12 μm) employed for our interacting/merging sample, we note a strong and consistent (similar non-linear behaviour) relationship between the TIR/radio and TIR/MIR ratios. Finally, we show that already at z < 0.1, qTIR exhibits a dependence on stellar mass, with more massive galaxies displaying a lower qTIR.