Interacting Galaxies NGC 4438 and NGC 4435 (Arp 120)

It is likely that the distorted shape of NGC 4438 was the result of a close encounter with NGC 4435 (and possibly M86) many millions of years ago. Both galaxies contain populations of old yellow stars colour whilst the outer regions of NGC 4438 are distinctly blue, an indication of a second population containing hot young stars. The tidal interactions caused a burst of star formation and disruption of an equatorial dust lane into a series of dark patches. There is also a dust lane running through the core of NGC 4438. Curiously NGC 4435 does not appear to have suffered much disruption during the encounter; distance ~55Mlys.