Last Updated on July 31, 2026 by Staff
Astronomers have taken pictures of the IC 1101 galaxy. This has helped them figure out how big the IC 1101 galaxy really is. For a time scientists knew the IC 1101 galaxy was huge. The outer parts of the IC 1101 galaxy were too faint and blended in with the surrounding galaxies making it hard to tell where the IC 1101 galaxy actually ended.
Now using deep observations from the Isaac Newton Telescope researchers have found the edge of the IC 1101 galaxy for the first time. They found out that the IC 1101 galaxy is 520 kiloparsecs across, which is almost 1.7 million light-years. The IC 1101 galaxy also has a lot of stars about 3.4 trillion times the mass of the Sun in stars. This makes the IC 1101 galaxy one of the stellar systems ever seen.
The research has been published on the arXiv preprint server. It gives us ideas about how big galaxies like the IC 1101 galaxy keep growing over billions of years.
Cosmic Giant
The IC 1101 galaxy is at the center of a group of galaxies called Abell 2029. The IC 1101 galaxy is a kind of galaxy called a Brightest Cluster Galaxy. These galaxies are the biggest and brightest in their groups. They form when smaller galaxies merge together over a time.
The IC 1101 galaxy did not form at once. It grew by absorbing galaxies over billions of years. Each time the IC 1101 galaxy collided with another galaxy it got bigger and bigger. The IC 1101 galaxy has a lot of stars, gas and dark matter.
One big problem with studying galaxies like the IC 1101 galaxy is that their outer stars blend in with the surrounding light. This light is called light. It is created by stars that are floating between galaxies.
Because of this astronomers have had a time figuring out where the IC 1101 galaxy ends and where the surrounding group of galaxies begins.
Deep Imaging
To solve this problem the researchers used a camera on the Isaac Newton Telescope to take very deep pictures of the IC 1101 galaxy.
Taking deep pictures was not enough. The light from hundreds of stars in front of the IC 1101 galaxy was. Making it hard to see the faint outer parts of the IC 1101 galaxy.
So the scientists made a special math model to remove this scattered light. They subtracted the glow from over 250 stars in front of the IC 1101 galaxy. This revealed faint structures around the IC 1101 galaxy.
This allowed them to measure the light from the IC 1101 galaxy more accurately than before. They finally found the edge of the IC 1101 galaxy.
Massive Scale
The pictures showed that the IC 1101 galaxy is 260 kiloparsecs across. This means it is 520 kiloparsecs across or roughly 1.7 million light-years.
To understand how big this is consider our Milky Way Galaxy. It is about 30 kiloparsecs across. This means the IC 1101 galaxy is 17 times bigger than the Milky Way Galaxy.
The IC 1101 galaxy has a lot of mass. Researchers think it has about 3.4 trillion times the mass of the Sun in stars. The Milky Way Galaxy has less mass, only about 1 to 1.5 trillion times the mass of the Sun.
This makes the IC 1101 galaxy one of the galaxies ever found.
Growing
The most exciting thing is that the IC 1101 galaxy is still growing. Beyond its edge astronomers found eight faint stellar structures. These structures are extending into the surrounding group of galaxies.
Some of these structures match with X-ray disturbances in the gas around the group of galaxies. These disturbances happened when another group of galaxies collided with this group 2-3 billion years ago.
This shows that the IC 1101 galaxy is still absorbing galaxies and material. It still is. Getting bigger.
The findings support the idea that big galaxies keep evolving over time through mergers. Future observations with telescopes may reveal more about how galaxies, like the IC 1101 galaxy, become so big. The study also shows how advanced imaging can help us understand how galaxies evolve on a scale.