 the two merging nuclei, either at 3.5 cm or at 20 cm. In
fact, \citet{galli04} see even three radio components in VLBA  observations of
the nuclear region, two of which are likely to be Seyfert nuclei, based on
their radio powers and brigthness temperatures, and one which could be a radio
supernova. One of the Seyfert nuclei also has jet-like extensions. According
to \citet{lira02} the AGN component has a bolometric luminosity of about
5~$\times$~10$^{45}$~erg~s$^{-1}$, making NGC~6240 a very powerful Seyfert galaxy.
Only one peak is seen in the H$_{2}$ line observations of \citet{werf93}, who
interpret the central peak to be located between the two nuclei as a result of
a strong collision shock in the ISM (see Fig.~\ref{ngc6240h2}). The recent
H$_{2}$ 1--0 S(1) observations by \citet{max05} show a bridge of warm molecular
gas between the northern and southern active nuclei. A similar offset of the
peak from the nuclei is seen in the maps of \citet{tecza00}. The [\ion{Fe}{2}]
1.64~$\mu$m and Br$\gamma$ emission, on the other hand, coincide with the two
nuclei \citep{werf93,tecza00}. The SF activity in the nuclear
region was recently studied by \citet{pasq04}, who found extremely high SF and
SN rates in the nucleus (see Table~\ref{table5}). \citet{gerssen04} studied the
high  resolution morphology using {\it HST} NICMOS and WFPC2 observations. They
see up to four nuclear components, and a superwind from a nuclear starburst
roughly in the east--west direction. Recent Chandra observations of the nucleus
of NGC~6240 have revealed two main emission peaks, implying the existence of
two supermassive black holes, associated with the two merging nuclei
\citep{komo03}. The high SF and SN rates presumably drive a powerful
superwind.  The radio continuum emission in the nuclear region is most likely a
combination of synchrotron emission from electrons created by the high SN rate,
and non-thermal emission from the active nuclei \citep{beswick01}. Scaling the
20 cm emission (assuming it is all nonthermal and using a spectral dependence
of S $\propto$ $\nu$$^{-0.6}$, 0.6 being a typical spectral index for the
galaxies in our sample that had both 6 cm and 20 cm images) to 3.5 cm and
subtracting it we estimate that a considerable fraction of the emission at 3.5
cm can be thermal, up to 60\%. However, the spectral index of the non-thermal
emission down to 3.5 cm is not known for NGC 6240.

\begin{figure*}[th]
\centering
\includegraphics[width=6in]{n6240h2radio.eps}
\caption{Gray-scale image of the H$_{2}$ 1--0 S(1) emission with 20-cm radio 
continuum contours overlaid in NGC~6240. The contour levels are at (5 8 16 
24 48 96 192 300 450) times the one sigma noise level.\label{ngc6240h2}}
\end{figure*} 

The most peculiar structure in this system is the extended western ``arm'' of
radio continuum emission, which has  several embedded peaks. This morphology
has been interpreted as a result of synchrotron emission from a superwind,
driven by the intense starburst in the nucleus \citep{col94}. Cosmic rays are
generated in SF regions and propagate into the magnetic features. Our
observation of the radio continuum morphology (the angle between the P.A. of
the underlying galaxy and the radio continuum emission) supports such a
scenario. It is likely that the superwind seen in detail in the
arcsec-resolution {\it HST} images of \citet{gerssen04}, is related to the
peculiar radio continuum structure. We note that NGC~6240 is the most radio
powerful galaxy in our sample, and has the highest SF and SN rates, together
with nuclear activity. Our new 3.5-cm data have a similar resolution to the
3.5-cm data discussed by \citet{col94}. We show our new data set for comparison
with the old data. \citet{anton85} published 6-cm data at a comparable
resolution. Those data reveal a similar overall morphology as our map at 20 cm,
but at a much lower sensitivity.

\subsubsection{NGC~6574}

NGC~6574 is a nearby Seyfert 2 galaxy. It is the only galaxy in our sample that
displays a central point-like radio continuum component, a circumnuclear ring,
and a connecting radio continuum feature between the two. Note that the ring
was not detected in the early VLA high resolution radio continuum observations
of \citet{vila90}, most likely because of inadequate sensitivity. Our new data
are a factor of five more sensitive than the old data published by
\citet{vila90}. The ``jet'' is one-sided and is only at the 3$\sigma$ level in
the 20-cm map (Figure~\ref{n6574fig}). At 3.5 cm, where no previous high
resolution data exist to our knowledge, there is a connection between the
nucleus and the circumnuclear ring on the opposite side of the nucleus at
6$\sigma$ level. This ``jet'' has a major-axis radius of about 10 arcsec (just
under 2 kpc). These ``jets'' lie close to the major axis of the galaxy, and
therefore are unlikely to represent any outflows perpendicular to the galaxy
disk. Interestingly, there is moderate strength H$_{2}$ emission near the end
of the southern ``jet'' (see Fig.~\ref{n6574fig}). An estimate of the thermal
emission in the 3.5 cm image, constructed in a similar way to what was
described above for NGC~6240, also shows that there is likely to be a
substantial thermal component to the 3.5 cm emission in the ring north of the
nucleus. The Br$\gamma$ emission at this location is weak, so the northeastern
radio continuum bridge is unlikely to be related to a ``jet'' striking the
circumnuclear ring and triggering of SF there. The nucleus seems to have only
nonthermal radiation at 3.5 cm, while elsewhere in the ring the thermal
contribution could be up to 50\%, based on estimating the nonthermal
contribution from the 20 cm image by scaling it down to 3.5 cm with a spectral
index of 0.6. There appears to be a nuclear stellar (and perhaps gaseous, seen
by \citeauthor{kot00} \citeyear{kot00}) bar at a position angle of about 150
degrees, inside the ring. The strongest radio continuum emission occurs in the
ring east of the nucleus, as does the strongest Br$\gamma$ and H$_{2}$ 1--0
S(1) emission (see Fig.~\ref{n6574fig}). There is a fairly good coincidence
between the H$_{2}$ 1--0 S(1) and radio continuum emission, although there is a
region of moderately strong radio continuum emission south--southeast of the
nucleus in the ring that does not show up in the near-infrared line emission.
However, the absence of any detected H$_{2}$ emission there is likely to be due
to the narrow bandwidth of the  Fabry--Perot interferometer filter used in the
observations of \citet{kot00}. An archival {\it HST} WFPC2 ultraviolet image at
3000~\AA~shows a patchy star-forming ring, but the detailed spatial correlation
with the strongest radio and NIR line emission is poor within the ring.

\begin{figure*}[th]
\centering
\includegraphics[width=6in]{ngc6574radio.eps}
\caption{Gray-scale image of the H$_{2}$ 1--0 S(1) emission with 20-cm radio 
continuum (black) and Br$\gamma$ (light grey) contours overlaid in NGC~6574. 
The radio continuum contour levels are at (3 4 6 8 12 16 24) times the one sigma
noise level.\label{n6574fig}}
\end{figure*}

\subsubsection{NGC~6764}

There is a remarkable outflow structure clearly revealed by our radio
continuum images of NGC~6764, approximately perpendicular to the galaxy major
axis, and therefore probably perpendicular to the plane of the galaxy (see
Figure~\ref{fig1}). The only other earlier data at comparable resolution at 
20 cm were published by \citet{condon82}, but those data have a sensitivity
that is a factor of two worse than in our new data. The 6-cm and 21-cm
Westerbork maps by \citet{baum93} have a lower spatial resolution and
sensitivity than our maps. Our map shows clear cavities in  the radio
continuum emission, not shown by the