2024/05/01 by Robin H W Cook, L. J. M. Davies, Cook, Robin H. W. +43 · 1 citation
Earth and Planetary Sciences · Engineering · Physics and Astronomy · #Astronomical Observations and Instrumentation #Astrophysics of Galaxies (astro-ph.GA) #FOS: Physical sciences #Geophysics and Gravity Measurements #Radio Astronomy Observations and Technology
paper · pdf · doi:10.48550/arxiv.2405.00337
openalex publication_date 2024/05/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The tight relationship between infrared luminosity (LTIR) and 1.4 GHz radio continuum luminosity (L1.4GHz) has proven useful for understanding star formation free from dust obscuration. Infrared emission in star-forming galaxies typically arises from recently formed, dust-enshrouded stars, whereas radio synchrotron emission is expected from subsequent supernovae. By leveraging the wealth of ancillary far-ultraviolet - far-infrared photometry from the Deep Extragalactic VIsible Legacy Survey (DEVILS) and Galaxy and Mass Assembly (GAMA) surveys, combined with 1.4 GHz observations from the MeerKAT International GHz Tiered Extragalactic Exploration (MIGHTEE) survey and Deep Investigation of Neutral Gas Origins (DINGO) projects, we investigate the impact of timescale differences between far-ultraviolet - far-infrared and radio-derived star formation rate (SFR) tracers. We examine how the SED-derived star formation histories (SFH) of galaxies can be used to explain discrepancies in these SFR tracers, which are sensitive to different timescales. Galaxies exhibiting an increasing SFH have systematically higher LTIR and SED-derived SFRs than predicted from their 1.4 GHz radio luminosity. This indicates that insufficient time has passed for subsequent supernovae-driven radio emission to accumulate. We show that backtracking the SFR(t) of galaxies along their SED-derived SFHs to a time several hundred megayears prior to their observed epoch will both linearise the SFR-L1.4GHz relation and reduce the overall scatter. The minimum scatter in the SFR(t)-L1.4GHz is reached at 200 - 300 Myr prior, consistent with theoretical predictions for the timescales required to disperse the cosmic ray electrons responsible for the synchrotron emission.