Warm Molecular Gas in Galaxy-Galaxy Merger NGC 6090

We present observations of the CO 2-1 and 3-2 transitions toward the merginggalaxies of NGC6090 with the Submillimeter Array (SMA) (The Submillimeter Array(SMA) is a joint project between the Smithsonian Astrophysical Observatory andthe Academia Sinica Institute of Astronomy and Astrophysics, and is funded bythe Smithsonian Institution and the Academia Sinica.). The high resolution COdata reveal three gas concentrations. The main component is peaking in theoverlap region between the two galaxies, where the near-IR a nd radio continuumemission are weak. The CO 2-1 emission from the face-on galaxy NGC6090E issomewhat stronger than that from the edge-o n galaxy NGC6090W. The CO 3-2 emission peaks in the overlap region, similar to the CO 2-1emission . More than 50% of the CO 3-2 emission arises from the 2$''$ (1.2 kpc)area of the overlap region. There appears to be CO 3-2 emission toward thenuclear region and the north-west arm of NGC6090E, while no CO 3-2 emission isdetected toward NGC6090W. Unlike the CO gas, most of the radio continuumemission comes from NGC6090E. The strong CO emission, together with the weakradio continuum emission, suggests that star formation in the overlap regionhas not proceeded long enoug h to produce significant numbers of supernovaewhich would be detectable due to their radio continuum emission.Comment: Accepted by ApJ