Mergers and Acquisitions

One from manyThis is an odd galaxy known as NGC 1487. It’s not a single galaxy but two or more galaxies in the act of merging. Each of the old galaxies has lost almost all traces of its original appearance as the stars and gas have been thrown about by gravitational interactions. Unless one of the merging galaxies is very much bigger than the other(s), galaxies are always disrupted by the violence of the merging process, so it’s essentially impossible to determine exactly what the original galaxies looked like or how many of them there were. In this case, it may be that this NGC 1487 is the merger of several dwarf galaxies that were previously part of a small group.

Although older yellow and red stars can be seen in the outer regions of the new galaxy, its general appearance is dominated by bright blue stars that probably formed in a burst of star formation triggered by the merger.

Image Credit: ESA / NASA

An Unusual Dwarf

A case of suspended animation?The speckling of stares in this image taken by the Hubble Space Telescope image seems to show an array of different cosmic objects, actually forms a single body—the nearby dwarf galaxy known as Leo A. Its few million stars are so sparsely distributed that distant galaxies in the background can be seen behind it. Leo A is about 2.5 million light-years from Earth and is a member of the Local Group of galaxies, a group that includes the Milky Way.

Image Credit: NASA / ESA