Imaging Carbon Monoxide Emission in the Starburst Galaxy NGC 6000
  We present measurements of carbon monoxide emission in the central region of
the nearby starburst NGC 6000 taken with the Submillimeter Array. The J=2-1
transition of 12CO, 13CO, and C18O were imaged at a resolution of ~3''x2''
(450x300 pc). We accurately determine the dynamical center of NGC 6000 at
R.A(J2000.0)=15h49m49.5s and dec(J2000.0)=-29d23'13'' which agrees with the
peak of molecular emission position. The observed CO dynamics could be
explained in the context of the presence of a bar potential affecting the
molecular material, likely responsible for the strong nuclear concentration
where more than 85% of the gas is located. We detect a kinematically detached
component of dense molecular gas at relatively high velocity which might be
fueling the star formation. A total nuclear dynamical mass of 7x10^9 Msun is
derived and a total mass of gas of 4.6x10^8 Msun, yielding a Mgas/Mdyn~6%,
similar to other previously studied barred galaxies with central starbursts. We
determined the mass of molecular gas with the optically thin isotopologue C18O
and we estimate a CO-to-H2 conversion factor X(CO)=0.4x10^20 cm-2/(K km s-1) in
agreement with that determined in other starburst galaxies.
