This dual achievement not only expands scientists’ understanding of the black hole population in the universe but also sets the stage for further explorations the formation of the first black holes to form in the universe and their role in galaxy evolution.

With DESI’s early data, the team was able to obtain an unprecedented dataset that includes the spectra of 410,000 galaxies, including roughly 115,000 dwarf galaxies—small, diffuse galaxies containing thousands to several billions of stars and very little gas. This extensive set would allow Pucha and her team to explore the complex interplay between black hole evolution and dwarf galaxy evolution.

While astrophysicists are fairly confident that all massive galaxies, like our Milky Way, host black holes at their centers, the picture becomes unclear as you move toward the low-mass end of the spectrum. Finding black holes is a challenge on its own but identifying them in dwarf galaxies is even more difficult due to their small sizes and the limited ability of our current instruments to resolve the regions close to these objects. An actively feeding black hole, however, is easier to spot.

“When a black hole at the center of a galaxy starts feeding, it unleashes a tremendous amount of energy into its surroundings, transforming into what we call an active galactic nucleus,” said Pucha. “This dramatic activity serves as a beacon, allowing us to identify hidden black holes in these small galaxies.”

The study is online as a pre-print ahead of publication in The Astrophysical Journal.

Read the full story by Lisa Potter in @ The U.