The infrared-radio correlation of star-forming galaxies is strongly M$_{\star}$-dependent but nearly redshift-invariant since z$\sim$4

Understand

Several works in the past decade have used the ratio between total (rest 8-1000$\mu$m) infrared and radio (rest 1.4~GHz) luminosity in star-forming galaxies (q$_{IR}$), often referred to as the "infrared-radio correlation" (IRRC), to calibrate radio emission as a star formation rate (SFR) indicator.

• Previous studies constrained the evolution of q$_{IR}$ with redshift, finding a mild but significant decline, that is yet to be understood.
• For the first time, we calibrate q$_{IR}$ as a function of \textit{both} stellar mass (M$_{\star}$) and redshift, starting from an M$_{\star}$-selected sample of $>$400,000 star-forming galaxies in the COSMOS field, identified via (NUV-r)/(r-J) colours, at redshifts 0.1$<$z$<$4.5.
• Within each (M$_{\star}$,z) bin, we stack the deepest available infrared/sub-mm and radio images.