If our galaxy is typical, then it is already interacting with its large neighbor, the Andromeda Galaxy.
The fact is that galaxies turned out to be much larger than previously thought. This is evidenced by the results of a new study by scientists from the ARC Center of Excellence for Sky Astrophysics (CAASTRO, USA), who studied the galactic halo thanks to the super-sensitive 10-meter Keck telescope in Hawaii, EurekAlert reports.
The halo of gas surrounding the stellar disk makes up about 70% of the galaxy’s mass – excluding dark matter – but has remained something of a mystery until now, the paper notes.
It is noted that the researchers managed to photograph this halo of matter around the galaxy for the first time:
- In the past, scientists could only observe such gas by measuring the light from a background object, such as a quasar, being absorbed by the gas. This limited the image to a pencil-like beam;
- A new study, observing the circumgalactic environment of a galaxy located 270 million light-years from Earth, used advanced deep imaging techniques that were able to reveal a cloud of glowing gas beyond the galaxy at least 100,000 light-years away in space.
To get a sense of the vastness of this gas cloud, consider that the galaxy’s starlight — what we normally think of as a disk — extends just 7,800 light-years from its center, the paper notes.
This study observed the physical connection of hydrogen and oxygen from the center of the galaxy far into space and showed that the physical conditions of the gas are changing.
We can now see where the galaxy’s influence ends, the transition where it becomes part of a larger galaxy surrounding it, and eventually where it joins the wider cosmic web and other galaxies. These are usually fuzzy boundaries, the researchers note. “But in this case, we seem to have found a fairly clear boundary in this galaxy between its interstellar medium and its circumgalactic medium.”
In the study, scientists observed how stars ionize gas with their photons inside the galaxy.
In the circumgalactic environment, the gas is heated by something other than the typical conditions inside galaxies, this probably includes heating from diffuse radiation from collective galaxies in the Universe, and perhaps shock waves make some contribution, the scientists note. – It is this interesting change that is important and gives some answers to the question of where the galaxy ends.
It is noted that the results obtained by the researchers may have implications for understanding how different galaxies interact and how they can influence each other.
In all likelihood, the circumgalactic environments of our Milky Way and Andromeda are already intersecting and interacting, the researchers note.
Source: EurekAlert
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I am David Wyatt, a professional writer and journalist for Buna Times. I specialize in the world section of news coverage, where I bring to light stories and issues that affect us globally. As a graduate of Journalism, I have always had the passion to spread knowledge through writing.