Employees of the NOIRLab research center have published a photograph taken by the Dark Energy Camera (DECam). It shows the galaxy M83. It is also known by the nickname Southern Pinwheel, due to its distinctive spiral arm shape.
The galaxy was discovered in 1752 by French astronomer Nicolas Louis de Lacaille. Three decades later, it was listed by Charles Messier in his famous catalog of astronomical objects under the designation M83. There it was described as a “starless nebula”, reflecting the extreme limitations of scientific knowledge of galaxies at that time. Only in the 20th century, thanks to the work of Edwin Hubble, astronomers realized that similar M83 objects were actually other galaxies like our Milky Way.
We now know that M83 is located at a distance of 12 million light-years from Earth. The diameter of its disk is 50,000 light-years. That’s about half the diameter of our galaxy. But although M83 is noticeably smaller than the Milky Way, it is much more active in forming new stars. The DECam image shows many characteristic pink spots covering its spiral arms. These are regions of active star formation, where new luminaries are forming right now.
Among these pink regions are bright blue clusters of hot young stars whose ultraviolet radiation has blown out the surrounding gas. At the galaxy’s core is a yellow central bulge. It’s made up of older stars. M83 also has a weak bar that connects its spiral arms to the core, supplying gas to it. Thanks to its high sensitivity, DECam was also able to capture the halo of M83, as well as the myriad of more distant galaxies in the background.
In addition to stellar maternity homes, M83 is also home to a large number of supernovae. Astronomers have recorded six flares in it in the last hundred years. And that’s just the tip of the iceberg. Astronomers estimate that the galaxy is filled with hundreds of thousands of supernova remnants.
This activity is likely the result of M83’s recent merger with another galaxy. In 2006, astronomers discovered a large cluster of mass at its center that resembles a second nucleus. It most likely contains a supermassive black hole. It is believed to be a remnant of another galaxy that was absorbed by M83 in the past. It is estimated that it will finally merge with the core of M83 in 60 million years.
Provided by NOIRLab
