Speaker
Description
We investigate whether radio emission primarily traces star formation in radio-quiet active galactic nuclei (RQ AGN). Our sample consists of 5223 galaxies detected by the MeerKAT International GHz Tiered Extragalactic Exploration (MIGHTEE) survey with multi-wavelength counterparts up to a z ≈ 6 limit. The radio sources were classified using the infrared-to-radio luminosity ratio (q$_{\rm IR}$), X-ray luminosity cuts, and mid-infrared colour cuts into RQ AGN, radio-loud AGN (RL AGN), and star-forming galaxies (SFGs). We calibrated the star formation rate (SFR)-1.4 GHz radio luminosity (L$_{\rm 1.4~GHz}$) relation for both RQ AGN and SFGs. We find that in both populations SFR correlates positively with L$_{\rm 1.4~GHz}$, with average Spearman’s rank correlation coefficients of 0.71 for RQ AGN and 0.76 for SFGs. The best-fit slope for RQ AGN is 0.795 ± 0.023, consistent with that of 0.755 ± 0.008 for SFGs. With these results, we conclude that radio continuum from RQ AGN primarily traces star formation. This implies that we trace free-free and synchrotron emission in star-forming regions of the host galaxy with the AGN jet component contributing less.
| Stream | Science or Engineering |
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