On Jan. 7, a group of astronomers from around the world, including some from the UW, made an astonishing discovery: a super-massive black hole, present in a galaxy thought incapable of sustaining such a thing.

"We were surprised ... we were pleasantly surprised," said Victor Debattista, the UW Fellowship recipient involved in the project. "We were expecting [the black hole] to be something different."

Not only is this only the second time a super-massive black hole has ever been observed in a dwarf galaxy, it's also only the third time that the center of a dwarf galaxy has ever been observed with what is known as a "double nucleus" at its heart.

The discovery itself was actually an accident. The researchers, hailing from institutions in Chile, Belgium and London, as well as the UW itself, were sifting through images taken by the Hubble Telescope in an effort to study the nuclei of dwarf galaxies.

They wanted to find out whether dwarf galaxies are spawned from tightly packed spherical collections of stars called "globular clusters," which are often seen orbiting a larger and more established galaxy.

While examining these galaxies, they came across one, tagged as Galaxy VCC128, which seemed to have a double nucleus.

Upon further study, it became apparent that the double nucleus was actually due to a dual collection of stars, held at each end of a gravitational ring surrounding a super-massive black hole.

Judging from the mass of the stars surrounding the black hole, it has an estimated mass between one million and 50 million times the mass of the sun in our solar system.

This discovery will go a long way toward understanding the mechanics of how larger black holes form.

"The dwarf galaxies [similar to this one] offer us the opportunity to study the properties of the building blocks of today's massive galaxies and the super-massive black holes they host," said Sven De Rijcke, the Belgian researcher involved in the project.

Reach reporter Anthony Erickson at anthonyerickson@thedaily.washington.edu.