N. Seymour, C. L. Hale, I. H. Whittam, P. Oesch, A. Covelo-Paz, S. Wuyts, J. Afonso, R. A. A. Bowler, J. Grundy, R. Jaiswar, M. Jarvis, A. M. Matthews, R. Meyer, C. Neufeld, N. Reddy, I. Shivaei, D. Smith, R. G. Varadaraj, M. Wozniak, L. Jung
Abstract
As radio emission from normal galaxies is a dust-free tracer of star formation, tracing the star formation history of the Universe is a key goal of the Square Kilometre Array and the Next-Generation Very Large Array. In order to investigate how well radio luminosity traces star formation rate (SFR) in the early Universe, we have examined the radio properties of a JWST Paα sample of galaxies at 1.0 ≲ z ≲ 1.8. In the GOODS-S field, we cross-matched a sample of 506 FRESCO Paα emitters with the 1.23 GHz radio continuum data from the MeerKAT MIGHTEE survey, finding 47 detections. After filtering for active galactic nuclei (via X-ray detections, hot mid-infrared dust, and extended radio emission), as well as blended sources, we obtained a sample of star-forming galaxies comprising 11 cataloged radio detections, 18 noncataloged detections (at ≍3σ─5σ), and 298 undetected sources. Stacking the 298 undetected sources, we obtain a 3.3σ detection in the radio. This sample, along with a local sample of Paα emitters, lies along previous radio luminosity/SFR relations from local (<0.2) to high redshift (z ∼ 1). Fitting the FRESCO data at 1.0 ≲ z ≲ 1.8, we find log(L1.4GHz)= (1.31 ± 0.17) × log(SFRPaα)+ (21.36 ± 0.17), which is consistent with other literature relations. We can explain some of the observed scatter in the L1.4GHz/SFRPaα correlation by a toy model in which the synchrotron emission is a delayed/averaged tracer of the instantaneous Paα SFR by ∼10/75 Myr.
Keywords
Extragalactic radio sources / Galaxy evolution / Starburst galaxies / 508 / 594 / 1570
The Astrophysical Journal
Volume 998, Number 306, Page 12
2026 February
