For The First Time, Astronomers See Black Holes in Dwarf Galaxies About to Collide

Astronomers have discovered proof of a pair of dwarf galaxies with massive black holes on a crash path with one another for the first time. Actually, they've discovered two pairs instead of just one.

The first merger pair of dwarf galaxies is located in the galaxy cluster Abell 133, which is about 760 million light-years from Earth, and the second pair is located in the galaxy cluster Abell 1758S, which is about 3.2 billion light-years distant.

It is anticipated that these observations and subsequent research will reveal some of the mysteries of the very early Universe, when couples of colliding dwarf galaxies with black holes were much more frequent.

Astronomers have discovered numerous instances of black holes on collision paths in big galaxies that are nearby, but hunts for them in dwarf galaxies are much more difficult and have, up until now, failed, according to research leader Marko Micic of the University of Alabama.

These studies are difficult because it is difficult to see the fainter light signatures of these galaxy couples due to their smaller sizes. While our own Milky Way contains the equal of about 60 billion Suns, these galaxies have stars with total masses that are less than about 3 billion times that of the Sun.

The researchers used data from several observatories, including optical data from the Canada-France-Hawaii Telescope, infrared data from WISE, and X-ray findings from Chandra, to make their discovery. The X-ray data, which detected the stronger signs being emitted by the black hole couples, was essential.

The Abell 133 merging seems to be much further along, as evidenced by the fact that it only has the moniker Mirabilis. That's named after a critically imperiled hummingbird that is noted for having a very long tail in allusion to the collision-induced long tail seen around these two galaxies.

With respect to Abell 1758S, the dwarf galaxies are not as closely knit together and are given the titles Elstir and Vinteuil (after characters from Marcel Proust's In Search of Lost Time). These galaxies and their black holes don't appear to have combined to the same degree; instead, it appears that they are presently connected by a bridge of stars and gas.

Astrophysicist Olivia Holmes of the University of Alabama states, "Using these systems as analogs for ones in the early Universe, we can dig down into issues about the first galaxies, their black holes, and the star formation the collisions produced."

These smaller, colliding galaxies are believed to have grown together over billions of years to form the bigger galaxies (like the Milky Way) that now predominate the Universe. They are referred to as our "galactic progenitors" by the experts.

We might even be able to learn more about how our own galaxy formed and progressed to its current state. Our native system still has a number of discrepancies that need to be explained.

As our telescope and picture processing technology continues to advance, astronomers will be able to confirm that these dual active galactic nuclei (DAGN) are indeed what they claim to be and gather more information about them.

According to astronomer Jimmy Irwin from the University of Alabama, "Follow-up observations of these two systems will enable us to investigate processes that are essential for comprehending galaxies and their black holes as infants."

The research has been accepted for publication in The Astrophysical Journal and is available to read on the preprint server arXiv.