CHANG-ES V: Nuclear Radio Outflow in a Virgo Cluster Spiral after a
  Tidal Disruption Event
  We have observed the Virgo Cluster spiral galaxy, NGC~4845, at 1.6 and 6 GHz
using the Karl G. Jansky Very Large Array, as part of the `Continuum Halos in
Nearby Galaxies -- an EVLA Survey' (CHANG-ES). The source consists of a bright
unresolved core with a surrounding weak central disk (1.8 kpc diameter). The
core is variable over the 6 month time scale of the CHANG-ES data and has
increased by a factor of $\approx$ 6 since 1995. The wide bandwidths of
CHANG-ES have allowed us to determine the spectral evolution of this core which
peaks {\it between} 1.6 and 6 GHz (it is a GigaHertz-peaked spectrum source).We
show that the spectral turnover is dominated by synchrotron self-absorption and
that the spectral evolution can be explained by adiabatic expansion (outflow),
likely in the form of a jet or cone. The CHANG-ES observations serendipitously
overlap in time with the hard X-ray light curve obtained by Nikolajuk \& Walter
(2013) which they interpret as due to a tidal disruption event (TDE) of a
super-Jupiter mass object around a $10^5\, M_\odot$ black hole. We outline a
standard jet model, provide an explanation for the observed circular
polarization, and quantitatively suggest a link between the peak radio and peak
X-ray emission via inverse Compton upscattering of the photons emitted by the
relativistic electrons. We predict that it should be possible to resolve a
young radio jet via VLBI as a result of this nearby TDE.
