Bibcode
Williams-Baldwin, D. R. A.; Baldi, R. D.; Beswick, R. J.; McHardy, I. M.; Carver, E.; Clifford, J.; Dullo, B. T.; Kill, N.; Krishnamoorthi, B.; Mutie, I. M.; Woodcock, O.; Argo, M. K.; Boorman, P.; Brinks, E.; Fenech, D. M.; Knapen, J. H.; Mathur, S.; Moldon, J.; Muxlow, T. W. B.; Pahari, M.; Wrigley, N. H.; Alberdi, A.; Baan, W.; Beri, A.; Cheng, X.; Green, D. A.; Healy, J.; Kharb, P.; Körding, E.; Lucatelli, G.; Panessa, F.; Puig-Subirà, M.; Romero-Cañizales, C.; Saikia, D. J.; Saikia, P.; Shankar, F.; Sharma, S.; Stevens, I. R.; Varenius, E.
Bibliographical reference
Monthly Notices of the Royal Astronomical Society
Advertised on:
5
2026
Citations
0
Refereed citations
0
Description
We present 5 GHz e-MERLIN radio images at 50 mas resolution of the nuclear regions of the Legacy e-MERLIN Multi-band Imaging of Nearby Galaxies survey (LeMMINGs): the deepest statistically complete radio-band survey of the local Universe ($\lt$120 Mpc), consisting of 280 galaxies spanning all morphological and nuclear types. We detect nuclear radio emission above a median $5\sigma$ threshold of 0.33 mJy beam$^{-1}$ in 68/280 sources (24 per cent), with core luminosities $10^{35}$─$10^{41.9}$ erg s$^{-1}$. The radio emission is attributed to active galactic nuclei (AGNs), circumnuclear star formation, or ─ in the case of NGC 3690 ─ a tidal disruption event. The brightest radio nuclei, with brightness temperatures $\ge 10^{6}$ K, reside in optically 'active' galaxies ─ LINERs and Seyferts. The detection rate for 'inactive' systems (H II and absorption-line galaxies), which may host low-luminosity AGNs (LLAGNs), is 8 per cent. Most detections (78 per cent) are compact ($\lt$10 pc), while the remaining 22 per cent show extended jet-like features (up to 380 pc). Compared to 1.5 GHz LeMMINGs data, the 5 GHz observations' superior resolution and spatial filtering resolve out large-scale structures, isolating genuine nuclear emission. Our results suggest that LLAGNs are the primary manifestation of black-hole activity in the local Universe in the form of compact jets and cores, with a preference for early-type hosts. The two LeMMINGs campaigns show that up to 30 per cent of the local galaxy population host a radio-active nucleus, highlighting the necessity of high-resolution high-sensitivity imaging for uncovering nuclear emission at the lowest luminosities.