14 DAY TRIAL // When it comes to analyzing and comparing spiral galaxies, their halos are among the most important factors to set them apart. Astronomers have known for a long time that it was their telescopes that did not necessary allow for them to identify such structures around more galaxies, and so it was no surprise that they were finally able to image a halo-like structure around a very renowned galaxy. For the new study, a team of experts looked at the popular cosmic “destination” Messier 81 (M81).
Using an advanced telescope, they learned that the cosmic structure did not only contain stars within its disks, but also inside the halo as well. This is very difficult to establish using normal observatories, for two simple reasons. One, some of them are simply not as complex as such observations require, and secondly, their field of view is too narrow to identify the existence of the halo. When this happens, the telescopes only see individual stars outside the brightest parts of a galactic disk.
For studying Messier 81, astronomers at the National Astronomical Observatory of Japan used the large Subaru Telescope. The instrument is considerable in size, featuring a 27-foot (8.2-meter) primary mirror that is capable of producing highly-detailed images of the night sky. The research team combined this trait with the wide field-of-view of the Prime Focus Camera (Suprime-Cam) instrument on the observatory. This allowed them to look at a sufficiently-large portion of M81 to infer the existence of the halo. Analyzing this formation could give experts additional clues about how early galaxies appeared and developed, Space reports.
Experts say that various types and shapes of halos can be used as clear indicators for various properties of the spiral galaxies around which they developed. They can be viewed as extended structures existing around their host galaxies, and they can yield important clues as to the factors that governed the formation of those structures in the early days of the Universe. M81, one of the most popular astronomical attractions in the sky, is located about 11.7 million light-years away from Earth, in the direction of the constellation Ursa Major. The group that contains it, called the M81 Group, features about 34 galaxies.