This Tiny Galaxy Has a Pretty Big Black Hole

By Passant Rabie
published

An unusual pair: a dwarf galaxy with a supermassive black hole.

A tiny dwarf galaxy may be hosting a supermassive black hole, an unusual occurrence that could provide clues as to how galaxies were formed in the first place.

Astronomers using the Hubble Space Telescope observed the galaxy, located around 30 million light-years away from Earth, and found indications of a supermassive black hole at its core.

While it is known that nearly all galaxies the size of, or larger than, the Milky Way harbor a supermassive black hole at their core, there is less information about smaller galaxies. Astronomers believe that there is a correlation between the size of a galaxy and that of the black hole it is hosting — the bigger the galaxy, the bigger the black hole. 

Related: Black Holes of the Universe (Gallery)

However, this galaxy, dubbed ESO 495-21, is proving that size doesn't always matter. The galaxy measures at only 3% the size of the Milky Way, and its black hole is over a million times the mass of our sun, while the Milky Way's black hole is four million times the sun's mass, according to a statement from NASA and the European Space Agency, who jointly operate the Hubble Space Telescope.

Due to this unusual pairing, the dwarf galaxy may be useful in learning more about the origins of galaxies and how they evolve over time, according to the statement. 

ESO 495-21 is also known for being a starburst galaxy, meaning that it forms a large number of stars at high rates (1,000 times faster than the Milky Way.) 

Hubble observed this tiny galaxy hosting a supermassive black hole. (Image credit: NASA, ESA, W. Vacca)

Due to its small size, irregular shape and star cluster formation, astronomers believe that the dwarf galaxy is one of the first to have formed in the cosmos. Therefore, finding a supermassive black hole at its core could indicate that black holes were formed first in the cosmos while the galaxies evolved around them, according to the statement.

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Passant Rabie
Passant Rabie
Former Contributing Writer

Passant Rabie is an award-winning journalist from Cairo, Egypt. Rabie moved to New York to pursue a master's degree in science journalism at New York University. She developed a strong passion for all things space, and guiding readers through the mysteries of the local universe. Rabie covers ongoing missions to distant planets and beyond, and breaks down recent discoveries in the world of astrophysics and the latest in ongoing space news. Prior to moving to New York, she spent years writing for independent media outlets across the Middle East and aims to produce accurate coverage of science stories within a regional context.