When astronomers look at a galaxy in fine detail, they want the highest resolution they can get. They want to look at it in as many wavelengths of light as possible. They want to KNOW what’s in that galaxy. Why? For one thing, peering at a galaxy gives many clues about its past — what its rates of star formation have been, where it’s producing stars now, what’s in its core, and insight into the ages of its different populations of stars. Did it collide with another galaxy in the past? Did smaller galaxies coalesce to make it?
Observers using the European Space Agency’s Very Large Telescope, outfitted with an infrared-sensitive instrument called HAWK-1, have gotten one of the clearest looks at a nearby galaxy called M83. It lies some 15 million light-years away in the direction of the constellation Hydra, and gives astronomers a chance to look at a galaxy that is, in many ways, similar to our own Milky Way. M83 has spiral arms, and if you look closely at the image, you can see reddish clouds that are the incubators of young stars.
M83 is also fascinating because it has a higher than normal number of supernovae occurring. You get supernovae when massive, hot stars explode and spread their atmospheres and much of their mass to interstellar space. You get massive hot stars when a galaxy is boiling with star formation. So, sometime in the past, M83 was a busy little star-producing factory. Today when we look at it in optical light (the kind of light we see with our eyes), we see a lot of dust spread out around the galaxy. To look through that dust, astronomers use instruments like HAWK-1, to get a clearer view of the details in the galaxy’s spiral arms and core. Click on the image above and study the larger version. You’ll love what you see!