The Milky Way is not alone. This has fairly been established for some time, as it has satellite galaxies near it. Another satellite galaxy has been added, as a faint satellite galaxy orbiting the Milky Way has been discovered.
The newly discovered satellite galaxy has been named Virgo I. It can be found near the constellation Virgo. At a magnitude of -0.8 in the optical waveband, the new satellite galaxy is the faintest one found so far.
There are 50 satellite galaxies to the Milky Way. Most of these satellite galaxies are dwarf spheroidal galaxies. About 40 of those satellite galaxies to the Milky Way belong to this group. They are also very faint, with luminosity below -8 in magnitude.
With such faint galaxies, most of them have been undetected for a long time. Most earlier telescopes have a diameter of only 2.5 to 4 meters, so only the brightest of these galaxies have been found, according to Phys Org. Only now, with more modern equipment, have these faint dwarf galaxies been found.
Researchers from Tohoku University have found the faint satellite galaxy. They used the Hyper Suprime-Cam and data from the ongoing Subaru Strategic Survey to find it. Also used is the 8.2 meter Subaru Telescope in finding it. What gave the satellite galaxy away is an overdensity of stars, which is a characteristic pattern of an ancient stellar system, as Daisuke Homma, a graduate student from Tohoku University, remarked.
While there are already a number of satellite galaxies found, the number is still short of those that the models predicted, as UPI reports. That means there are still undetected satellite galaxies that might still be there. This is known to be the missing satellite problem.
The finding of Virgo I might be the first step in finding the other satellite galaxies. This is the view of lead researcher Masashi Chiba of Tohoku University. He added that knowing what properties these satellite galaxies have will give astronomers a better understanding how the Milky Way was formed. Also of interest is a new family of stars in the Milky Way that could also show how the galaxy was formed.