Do irregular galaxies have supermassive black holes?

Many irregulars do not have supermassive black holes in their centers. These are typically the smallest irregular galaxies, like I Zwicky 18. Instead of black holes, many have “nuclear star clusters”, which are dense knots of many thousands of stars.

Do irregular galaxies have a shape?

Some irregular galaxies clearly look like two galaxies ran into each other! When it’s not clear what group the galaxy should go in, astronomers usually call the galaxy irregular. Galaxies that don’t have a spiral or elliptical shape are often called irregular galaxies.

Why irregular galaxies are shaped that way?

An irregular galaxy is the catchall name given to any galaxy that does not neatly fit into one of the categories of the Hubble classification scheme. They have no defined shape nor structure and may have formed from collisions, close encounters with other galaxies or violent internal activity.

Do all galaxies have a black hole at the center?

Astronomers believe that supermassive black holes lie at the center of virtually all large galaxies, even our own Milky Way. Astronomers can detect them by watching for their effects on nearby stars and gas.

Why are irregular galaxies so bent and non symmetrical?

Because of their close proximity to our galaxy, they were distorted by gravitational interactions into their current unusual shapes. Other irregular galaxies seem to have been created through mergers of galaxies.

How do galaxies get their shape?

The centrifugal force of the spinning gas cloud along with the gravitational pull within the clouds work together to give a galaxy its shape. All galaxies began with an elliptical shape, which is mostly a result of the centrifugal force of the spinning gas cloud. These four types or groupes are devided by their shape.

What do spiral and irregular galaxies have in common?

They have a bulge and halo, like spiral galaxies, but don’t have the flat disk of stars. The stars in ellipticals tend to be older. Irregular galaxies have no identifiable shape or structure to them. They are often chaotic in appearance, without a bulge or any trace of spiral arms.

Why are galaxies irregular in shape?

The fact that galaxies are irregular is not because they don’t have black holes. There is correlation there, but not causation. The shape is set by a variety of other processes, including supernova explosions (as seen by all those shells of gas in the image of I Zwicky 18).

What determines the shape of a galaxy without a black hole?

To address the second part of your question: The shape of the galaxy is not set by the central black hole. This is because the gravitational sphere of influence of a black hole is tiny compared to a galaxy. The fact that galaxies are irregular is not because they don’t have black holes.

Why do galaxies have slumbering Giants?

Most galaxies in the recent universe have slumbering giants in their centers. Sleeping giants can awake, however. When interactions with other galaxies, starbursts, or gas clouds falling into the centers of galaxies “wake up” central black holes, they can erupt again with an outburst of energy. This explains AGN in the nearby universe.

Where do black holes come from?

Since then, studies of stellar orbits have shown that even relatively tranquil galaxies like our own Milky Way harbour hefty black holes. Their origin remains a mystery, however. They may have been created by the gravitational collapse of giant gas clouds from which galaxies were formed, or from the merger of many smaller black holes over time.