Models for the Arp 220 eastern nucleus in ¹²CO J = 3–2 (orange lines) and ¹³CO J = 4–3 (purple lines) shown along with the observed line profiles at half-beam increments along the disk axis and perpendicular to the disk axis. The column density of the model in the central position is 1.3 × 10²⁵ H₂ cm⁻² for ¹²CO and 3.3 × 10²⁴ H₂ cm⁻² for ¹³CO. Moving either to the left or right one panel at a time, the models’ column density decreases to 8.3 × 10²⁴ H₂ cm⁻², 4.2 × 10²⁴ H₂ cm⁻², and 2.0 × 10²⁴ H₂cm ⁻² for ¹²CO and to 2.2 × 10²⁴ H₂ cm⁻², 1.2 × 10²⁴ H₂ cm⁻², and 6.5 × 10²³ H₂ cm⁻² for ¹³CO. Likewise, moving one panel at time in the vertical direction, the column density decreases to 2.9 × 10²⁴ H₂ cm⁻² and 3.1 × 10²³ H₂ cm⁻² for ¹²CO and to 9.3 × 10²³ H₂ cm⁻² and 1.4 × 10²³ H₂ cm⁻² for ¹³CO. For ¹²CO J = 3 → 2, 1 Jy/beam = 248 K, and for ¹³CO J = 4 → 3, 1 Jy/beam = 294.5 K. An interactive figure is available.

An interactive version of this figure is available in the online journal.