Submillimeter Array Observations of Extended CO (J=2-1) Emission in the Interacting Galaxy NGC 3627

We present moderate (similar to 5 '') and high angular resolution (similar to 1 '') observations of (CO)-C-12 (J = 2 - 1) emission toward the nearby interacting galaxy NGC 3627 taken with the Submillimeter Array (SMA). These SMA mosaic maps of NGC 3627 reveal a prominent nuclear peak, inter-arm regions, and diffuse, extended emission in the spiral arms. A velocity gradient of similar to 400-450 km s(-1) is seen across the entire galaxy with velocity dispersions ranging from less than or similar to 80 km s(-1) toward the nuclear region to less than or similar to 15 km s(-1) in the spiral arms. We also detect unresolved (CO)-C-13 (J = 2 - 1) line emission toward the nuclear region, southern bar end, and in a relatively isolated clump in the southern portion of the galaxy, while no (CO)-O-18(J = 2 - 1) line emission is detected at a 3 sigma rms noise level of 42 mJy beam(-1) per 20 km s(-1) channel. Using RADEX modeling with a large velocity gradient approximation, we derive kinetic temperatures ranging from similar to 5 to 10K (in the spiral arms) to similar to 25 K (at the center) and H-2 number densities from similar to 400 to 1000 cm(-3) (in the spiral arms) to similar to 12,500 cm(-3) (at the center). From this density modeling, we find a total H-2 mass of 9.6 x 10(9) M-circle dot, which is similar to 50% higher than previous estimates made using a constant H-2-CO conversion factor, but is largely dependent on the assumed vertical distribution of the CO gas. With the exception of the nuclear region, we also identify a tentative correlation between star formation efficiency and kinetic temperature. We derive a galactic rotation curve, finding a peak velocity of similar to 207 km s(-1) and estimate a total dynamical mass of 4.94 +/- 0.70 x 10(10) M-circle dot at a galactocentric radius of similar to 6.2 kpc (121 '').