DISCOVERY OF A FLAT-SPECTRUM RADIO NUCLEUS IN NGC 3115
The early-type galaxy NGC 3115, at a distance of 10.2 Mpc, hosts the nearest billion-solar-mass black hole. Wong et al. recently inferred a substantial Bondi accretion rate near the black hole. Bondi-like accretion is thought to fuel outflows, which can be traced through their radio emission. This paper reports the discovery of a radio nucleus in NGC 3115, with a diameter less than 017 (8.4 pc), a luminosity at 8.5 GHz of 3.1 × 1035 erg s–1, and a flat spectrum (α = –0.23 ± 0.20, S∝να). The radio source coincides with the galaxy's photocenter and candidate X-ray nucleus. The emission is radio loud, suggesting the presence of an outflow on scales less than 10 pc. On such scales, the Bondi accretion could be impeded by heating due to disruption of the outflow.