Galaxy IC 2051 is what we consider a typical spiral galaxy, certainly not one of those peculiar or extreme objects in astronomy with enormous supermassive black holes or incredible star formation events. But even in its “averageness”, not much different from the middle ground occupied by our own galaxy, IC 2051 shines and sparkles in this breathtaking portrait taken by the Hubble Space Telescope.
The galaxy is roughly 85 million light-years from Earth, and is located in the southern constellation of Mensa. The picture was snapped on December 16 by Hubble as part of a study on galaxy bulges, how they form, and why there is such a variety of shapes within spiral galaxies, NASA revealed. In general terms, spiral galaxies can be broken down in a handful of components. There is the halo, which is a large and faint spherical region around the body of the main galaxy, and the disk, which is where the winding spiral arms are located.
At the center of the disk, we have the bulge. And at the bulge's center, in almost all spiral galaxies, there is a supermassive black hole. Evidence in the last few years showed that bulges are not just thicker than the disk, they have complex shapes, and new detailed observations suggest that previous broad categories used to describe these bulges hid the true nature of these structures.
Bulges appear to have composite morphologies. They are not simply disk-like, or spherical, or even boxy. They can be a mixture of all three and the variation in combinations produce the incredible diversity that surveys of spiral galaxies have been reporting.
But it’s not just about how they look. Bulges, just like the spiral arms, change over the lifetimes of galaxies and these changes are believed to be crucial when it comes to the evolution of a galaxy as a whole. And for this reason, astronomers are paying particular attention to the core of galaxies such as IC 2051.
IC 2051 has another similarity with the Milky Way, it is believed to be a barred spiral just like our own corner of the universe. Its bulge is not overly spherical but boxier. Bars in spirals might change in size and shape over time, and this could also impact the growth of the supermassive black hole.