From the UA News Center | Using NASA’s flagship space telescope for X-ray astronomy, students at The University of Alabama discovered the first evidence for giant black holes in dwarf galaxies on a collision course, according to findings published recently.
The result from NASA’s Chandra X-ray Observatory has important ramifications for understanding how the first wave of black holes and galaxies grew in the early universe.
“Astronomers have found many examples of black holes on collision courses in large galaxies that are relatively close by,” said Marko Mićić, UA graduate student in astronomy and physics who led the study. “But searches for them in dwarf galaxies are much more challenging and until now had failed.”
The research was part of the work of using X-ray satellite observatories to investigate the universe in the lab of Dr. Jimmy Irwin, professor of physics and astronomy. Along with Mićić, a doctoral student originally from Serbia, two undergraduate students, Olivia Holmes, a junior from Tuscaloosa; and Brenna Wells, a junior from Andalusia, are co-authors on the paper published in The Astrophysical Journal.
“Follow-up observations of these two systems will allow us to study processes that are crucial for understanding galaxies and their black holes as infants,” Irwin said.
Collisions between the pairs of dwarf galaxies identified in the new study have pulled gas toward the giant black holes they each contain, causing the black holes to grow. Eventually, the likely collision of the black holes will cause them to merge into much larger black holes. The pairs of galaxies will also merge into one.
The details of merging black holes and dwarf galaxies may provide insight into our Milky Way’s own past. Scientists think nearly all galaxies began as dwarf or other types of small galaxies and grew over billions of years through mergers.
“Most of the dwarf galaxies and black holes in the early universe are likely to have grown much larger by now, thanks to repeated mergers,” said Wells. “In some ways, dwarf galaxies are our galactic ancestors, which have evolved over billions of years to produce large galaxies like our own Milky Way.”
NASA’s Marshall Space Flight Center in Alabama manages the Chandra program. The Smithsonian Astrophysical Observatory’s Chandra X-ray Center controls science operations from Cambridge, Massachusetts, and flight operations from Burlington, Massachusetts.
A version of this story was originally published by NASA’s Chandra X-ray Observatory.