A significant breakthrough has been reported in the field of astrophysics with the identification of a vast collection of feeding black holes located in the centres of dwarf galaxies. These galaxies, which are smaller and less luminous than larger counterparts, contain varying numbers of stars but limited amounts of gas. The discovery, facilitated by the Dark Energy Spectroscopic Instrument (DESI), has provided researchers with an extensive sample of intermediate-mass black holes, often referred to as the «missing link» in black hole evolution.
Findings Published in The Astrophysical Journal
According to the study, this marks the largest group of active black holes ever observed in dwarf galaxies. The research team has also identified the most extensive collection of intermediate-mass black holes recorded to date.
Ragadeepika Pucha, researcher at the University of Utah and lead author of the study, explained in an official press release, that the energy released when a black hole begins feeding allows hidden black holes in smaller galaxies to be detected. This energy transformation results in what is known as an active galactic nucleus (AGN), enabling astronomers to observe these elusive celestial objects.
Intermediate-mass black holes are classified between stellar-mass black holes, which typically have up to 1,000 times the mass of the Sun, and supermassive black holes, which can be millions or even billions of times more massive. These mid-sized black holes are thought to be remnants of the first black holes that formed in the universe and are considered crucial in understanding the transition from smaller black holes to supermassive ones.
DESI’s Role in Identifying Hidden Black Holes
As reported by Space.com, The DESI instrument, mounted on the Nicholas U. Mayall 4-meter Telescope at the Kitt Peak National Observatory, has proven essential in uncovering these black holes. With its ability to capture light from 5,000 galaxies at once, DESI has provided an extensive dataset for analysis.
Using observations from the first year of its five-year mission, the research team examined data from 410,000 galaxies, including 115,000 dwarf galaxies. Out of these, 2,500 dwarf galaxies were identified as hosting active galactic nuclei, a significantly higher proportion than previous estimates. The study also identified approximately 300 intermediate-mass black holes, suggesting that many low-mass black holes have been overlooked in past research.
