1209.6602 (J. M. Wrobel et al.)

Discovery of a Flat-Spectrum Radio Nucleus in NGC 3115    [PDF]

J. M. Wrobel, K. Nyland

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 that 0.17 arcsec (8.4 pc), a luminosity at 8.5 GHz of 3.1 x 10^35 ergs/s and a flat spectrum (alpha = -0.23+/-0.20, flux density ~ frequency^alpha). 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.

View original: http://arxiv.org/abs/1209.6602