The Intermediate Mass Black Hole Candidate in the Center of NGC 404: New
  Evidence from Radio Continuum Observations
  We present the results of deep, high-resolution, 5 GHz Expanded Very Large
Array (EVLA) observations of the nearby, dwarf lenticular galaxy and
intermediate mass black hole candidate (M ~4.5 x 10^5 M_sun), NGC 404. For the
first time, radio emission at frequencies above 1.4 GHz has been detected in
this galaxy. We found a modestly resolved source in the NGC 404 nucleus with a
total radio luminosity of 7.6 +/- 0.7 x 10^17 W/Hz at 5 GHz and a spectral
index from 5 to 7.45 GHz of alpha = -0.88 +/- 0.30. NGC 404 is only the third
central intermediate mass black hole candidate detected in the radio regime
with subarcsecond resolution. The position of the radio source is consistent
with the optical center of the galaxy and the location of a known, hard X-ray
point source (Lx ~1.2 x 10^37 erg/s). The faint radio and X-ray emission could
conceivably be produced by an X-ray binary, star formation, a supernova remnant
or a low-luminosity AGN powered by an intermediate mass black hole. In light of
our new EVLA observations, we find that the most likely scenario is an
accreting intermediate mass black hole, with other explanations incompatible
with the observed X-ray and/or radio luminosities or statistically unlikely.
