A group of astronomers has discovered the smallest and most faint satellite galaxy that borders the nearest galactic neighbor of the Milky Way, the Andromeda Galaxy.
The ITSY-BITSY satellite galaxy is called Andromeda XXXV and is about 3 million light years from Earth. The discovery of the galaxy offers astronomers a useful comparative tool to study satellite galaxies on the outskirts of our own galaxy, the Milky Way. The team’s findings were published This week in the letters of Astrophysical magazine.
“These are completely functional galaxies, but they are approximately one millionth of the size of the Milky Way,” said Eric Bell, an astronomer from the University of Michigan and main author of the study, at a university release. “It’s like having a perfectly functional human being that is the size of a grain of rice.”
Andromeda XXXV is only about 20,000 times more massive than our sun, very small, even for a satellite galaxy. By way of comparison, the mass of the Milky Way is on 1.5 billion solar masses, And the most fornid galaxies can be up to 30 billion solar masses.
Although it is a complete galaxy, Andromeda XXXV is small enough to be trapped by Andromeda’s gravitational attraction, as well as the satellite galaxies of the Milky Way. The researchers observed Andromeda XXXV with the Hubble Space Telescope.
“This type of galaxy could only be discovered in a system, the Milky Way, in the past,” said Bell. “Now we can look at one around Andromeda and it is the first time we have done it outside our system.”
Hubble observations revealed that not only was Andromeda XXXV a satellite galaxy, but that it is small enough to ask questions about how such satellites even form stars.
“Most of the Milky Way satellites have populations of very old stars. They stopped forming stars about 10 billion years ago, ”said Marco Arias, the main author of the study, in the same launch. “What we are seeing is that similar satellites in Andromeda can form stars until a few billion years ago, loose 6 billion years.”
The finding can be used in the formation of differentiated satellite galaxies and the formation of stars in the milk manner from the conditions in other galaxies. There is anywhere between 100 billion 2 billion galaxies In the observable universe, but such small and weak galaxies are difficult to see, so you listen to the observations of Andromeda XXXV Hubble.
There are still outstanding questions about small galaxy, including how it survived the universe by heating almost 13 billion years ago. The “entire universe became a tub of boiling oil,” said Bell, and Andromeda XXXV is so small that he could have lost all his gas. But for several billions of years from then on, the galaxy continued to form stars.
More observations could clarify the nature of this laborious and persevering satellite, and by power, they could shed light on the satellite galaxies that revolve around the periphery of our own cosmic neighborhood.