Credit:ESA/Hubble & NASA
Acknowledgement: Judy Schmidt
Looking towards the constellation of Triangulum (The
Triangle), in the northern sky, lies the galaxy pair MRK 1034. The two
very similar galaxies, named PGC 9074 and PGC 9071, are close enough to
one another to be bound together by gravity, although no gravitational
disturbance can yet be seen in the image. These objects are probably
only just beginning to interact gravitationally.
Both are spiral galaxies, and are presented to our eyes
face-on, so we are able to appreciate their distinctive shapes. On the
left of the image, spiral galaxy PGC 9074 shows a bright bulge and two
spiral arms tightly wound around the nucleus, features which have led
scientists to classify it as a type Sa galaxy. Close by, PGC 9071 — a
type Sb galaxy — although very similar and almost the same size as its
neighbour, has a fainter bulge and a slightly different structure to
its arms: their coils are further apart.
The spiral arms of both objects clearly show dark patches of dust
obscuring the light of the stars lying behind, mixed with bright blue
clusters of hot, recently-formed stars. Older, cooler stars can be
found in the glowing, compact yellowish bulge towards the centre of the
galaxy. The whole structure of each galaxy is surrounded by a much
fainter round halo of old stars, some residing in globular clusters.
Gradually, these two neighbours will attract each other, the process
of star formation will be increased and tidal forces will throw out
long tails of stars and gas. Eventually, after maybe hundreds of
millions of years, the structures of the interacting galaxies will
merge together into a new, larger galaxy.
The images combined to create this picture were captured by Hubble's
Advanced Camera for Surveys (ACS). A version of this image was
submitted to the Hubble’s Hidden Treasures image processing competition by Judy Schmidt.
