We present CO ( 1-0 ) and H I ( 21-cm ) observations of the central region of the wet merger remnant NGC 34 .
The Combined Array for Research in Millimeter-wave Astronomy ( CARMA ) observations detect a regularly rotating disk in CO with a diameter of 2.1 kpc and a total molecular hydrogen mass of ( 2.1 \pm 0.2 ) \times 10 ^ { 9 } ~ { } M _ { \odot } .
The rotation curve of this gas disk rises steeply , reaching maximum velocities at 1 \arcsec ( 410 pc ) from the center .
Interestingly , H I observations done with the Karl G. Jansky Very Large Array show that the absorption against the central continuum has the exact same velocity range as the CO in emission .
This strongly suggests that the absorbing H I also lies within 1 \arcsec from the center , is mixed in and corotates with the molecular gas .
A comparison of H I absorption profiles taken at different resolutions ( 5 \arcsec - 45 \arcsec ) shows that the spectra at lower resolutions are less deep at the systemic velocity .
This provides evidence for H I emission in the larger beams , covering the region from 1 kpc to 9 kpc from the center .
The central rapidly rotating disk was likely formed either during the merger or from fall-back material .
Lastly , the radio continuum flux of the central source at mm wavelengths ( 5.4 \pm 1.8 mJy ) is significantly higher than expected from an extrapolation of the synchrotron spectrum , indicating the contribution of thermal free-free emission from the central starburst .