2022ApJ...937..120W

Dense gas is the key to understanding star formation in galaxies. We present high-resolution (∼3″) observations of CN 2-1 and CS 5-4 as dense gas tracers toward Arp 299, a mid-stage major merger of galaxies, with the Submillimeter Array. The spatial distribution of CN 2-1 and CS 5-4 are generally consistent with each other, as well as HCN 1-0 in the literature. However, different line ratios of CS 5-4 and CN 2-1 are found in the A, B, and C regions, with the highest value in B. Dense gas fraction decreases from IC 694 (A) to NGC 3690 (B) and the starburst in the overlap regions (C and C'), which indicates that circumnuclear upcoming starburst in A and B will be more efficient than that in the overlap region of Arp 299.