Estimating galaxy star formation rates from Murchison Widefield Array radio continuum emission
Year: 2026
Type: article
Abstract: We investigate the frequency dependence of the low-frequency infrared (IR)–radio correlation for nearby galaxies drawn from the Herschel Reference Survey (HRS), using radio continuum observations from the GaLactic and Extragalactic All-sky MWA (GLEAM) survey obtained with the Murchison Widefield Array (MWA). The GLEAM survey provides densely sampled flux densities across 20 sub-bands spanning 72–231 MHz, allowing detailed characterization of the low-frequency radio spectral energy distribution (SED). We analyze 18 nearby galaxies detected by GLEAM and examine the frequency dependence of the IR–radio correlation coefficient $q_\nu$. Among these galaxies, three sources show Seyfert or LINER signatures and may contain non-negligible AGN contributions to the radio continuum emission. We therefore use the remaining 15 predominantly star-forming galaxies as the primary sample for deriving the main calibration results. For the majority of the sample, the low-frequency radio continuum is well described by a single power-law spectral model from the GLEAM frequency range up to 1.5 GHz, with a median spectral index of $\gamma =-0.63$. The ensemble-averaged $q_\nu$ relation and its intrinsic scatter provide a practical calibration for converting low-frequency radio luminosities into star formation rates (SFRs), while explicitly quantifying the associated systematic uncertainty. Our results indicate that the low-frequency IR–radio correlation remains stable across the MWA bands for nearby star-forming galaxies, supporting the use of low-frequency radio continuum as a dust-unbiased tracer of star formation in the local Universe. These results provide a local benchmark for interpreting low-frequency radio continuum surveys and for future studies of radio-based SFR tracers with next-generation facilities such as the Square Kilometre Array.
DOI: 10.1093/pasj/psag096
Institutions: The Institute of Statistical Mathematics, Nagoya University, Tohoku University, SLAC National Accelerator Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, The University of Western Australia, ARC Centre of Excellence for All-sky Astrophysics, International Centre for Radio Astronomy Research, Commonwealth Scientific and Industrial Research Organisation
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7202349669