Dramatic Changes in Molecular Cloud Properties Across the Arp 299 Merger

Arp 299 is an IR-luminous (L_(IR) ≈ 8 x 10^(11) L_⨀) merger system of two galaxies, IC 694 and NGC 3690, at a distance of 40 Mpc. Its proximity and richness in molecular gas make it suitable for studying the effects of gravitational interactions and starburst activity on molecular cloud distributions, dynamics, and physical conditions. Previous low resolution observations (10 – 30″) indicated that the CO/^(13)CO 1–0 intensity ratio is unusually high, > 20, suggesting an unusual population of molecular clouds (Aalto et al. 1991; Casoli et al. 1992).