IC 630: Piercing the Veil of the Nuclear Gas
  IC 630 is a nearby early-type galaxy with a mass of $6 \times 10^{10}
M_{\odot}$ with an intense burst of recent (6 Myr) star formation. It shows
strong nebular emission lines, with radio and X-ray emission, which classifies
it as an AGN. With VLT-SINFONI and Gemini North-NIFS adaptive optics
observations (plus supplementary ANU 2.3m WiFeS optical IFU observations), the
excitation diagnostics of the nebular emission species show no sign of standard
AGN engine excitation; the stellar velocity dispersion also indicate that a
super-massive black hole (if one is present) is small ($M_{\bullet} = 2.25
\times 10^{5}~M_{\odot}$). The luminosity at all wavelengths is consistent with
star formation at a rate of about $1-2 M_{\odot}$/yr. We measure gas outflows
driven by star formation at a rate of $0.18 M_{\odot}$/yr in a face-on
truncated cone geometry. We also observe a nuclear cluster or disk and other
clusters. Photo-ionization from young, hot stars is the main excitation
mechanism for [Fe II] and hydrogen, whereas shocks are responsible for the
H$_2$ excitation. Our observations are broadly comparable with simulations
where a Toomre-unstable, self-gravitating gas disk triggers a burst of star
formation, peaking after about 30 Myr and possibly cycling with a period of
about 200 Myr.
