Mergers and Acquisitions: Coming Attractions

MRK 1034This pair of galaxies, called MRK 1034, lies in the constellation of Triangulum (The Triangle) in the northern sky. The two similar galaxies, PGC 9074 and PGC 9071, are close enough to one another to be tied together by gravity, but because we are seeing them as they are just beginning to interact gravitationally, there aren’t any large distortions noticeable. Yet. Wait a few hundred million years.

We see both spiral galaxies top down from our point of view. At the bottom PGC 9074 shows a bright bulge and two spiral arms tightly wound around its nucleus, features which classify it as a type Sa galaxy. PGC 9071 isa type Sb galaxy with a fainter bulge and the spiral arms further apart. The spiral arms of both show dark patches of dust mixed with blue clusters of recently-formed stars. Older, cooler stars can be found in the glowing, compact yellowish bulge towards the galactic centers, and each galaxy is surrounded by a much fainter round halo of old stars.

So what would we likely see after waiting a few hundred million years? As these two neighbors attract each other, the process of star formation will be increased, and tidal forces will throw out long tails of stars and gas. Eventually, the interacting galaxies should merge together into a new, larger galaxy.

Image Credit: NASA

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