Hubble captures galaxy pair Arp-Madore 2339-661

This placing picture from the NASA/ESA Hubble Area Telescope captures the interacting galaxy pair often known as Arp-Madore 2339-661. The Arp-Madore catalog is a group of strange galaxies, and this group’s specific peculiarity may be odder than first meets the attention, as there are three galaxies interacting right here, not simply two.

The 2 clearly outlined galaxies are NGC 7733 (smaller, decrease proper) and NGC 7734 (bigger, higher left). The third galaxy is at the moment known as NGC 7733N and is seen if you happen to look fastidiously on the higher arm of NGC 7733. There you may spot knot-like construction, glowing with a special coloration than the arm and obscured by darkish dust. This might simply go as a part of NGC 7733, however evaluation of the velocities (velocity and path) concerned reveals that this knot has a substantial further redshift.

This implies it is extremely doubtless its personal entity and never a part of NGC 7733. This galaxy group presents one of many many challenges that observational astronomers face: figuring out whether or not an astronomical object actually is only one, or a number of objects, one mendacity in entrance of one other as seen from Earth’s perspective.

All three galaxies lie fairly shut to one another, roughly 500 million light-years from Earth within the constellation Tucana, and, as this picture exhibits, they’re interacting gravitationally with each other. In truth, some science literature refers to them as a ‘merging group,’ which suggests they are going to finally turn out to be a single entity.