An international group of astronomers, led by researchers from The University of Texas at Austin’s Cosmic Frontier Center, has confirmed the most distant black hole ever observed. The black hole and its host galaxy, named CAPERS-LRD-z9, existed 500 million years after the Big Bang. This discovery allows scientists to examine a period when the universe was only about 3% of its current age.
“When looking for black holes, this is about as far back as you can practically go. We’re really pushing the boundaries of what current technology can detect,” said Anthony Taylor, postdoctoral researcher at the Cosmic Frontier Center and lead author of the study published August 6 in the Astrophysical Journal.
“While astronomers have found a few, more distant candidates,” added Steven Finkelstein, co-author and director of the Cosmic Frontier Center, “they have yet to find the distinct spectroscopic signature associated with a black hole.”
Astronomers used spectroscopy to split light into different wavelengths and look for evidence of fast-moving gas near black holes. As gas orbits and falls into a black hole, light from gas moving away appears redder while light from gas moving toward us appears bluer. “There aren’t many other things that create this signature,” explained Taylor. “And this galaxy has it!”
The team relied on data from the James Webb Space Telescope’s CANDELS-Area Prism Epoch of Reionization Survey (CAPERS) program for their search. JWST was launched in 2021 and provides detailed views into deep space.
“The first goal of CAPERS is to confirm and study the most distant galaxies,” said Mark Dickinson, co-author and CAPERS team lead. “JWST spectroscopy is the key to confirming their distances and understanding their physical properties.”
Initially appearing as a small point in telescope images, CAPERS-LRD-z9 was later identified as part of a class called “Little Red Dots.” These compact galaxies are present only within the first 1.5 billion years after the Big Bang and are characterized by their red color and unexpected brightness.
“The discovery of Little Red Dots was a major surprise from early JWST data, as they looked nothing like galaxies seen with the Hubble Space Telescope,” explained Finkelstein. “Now, we’re in the process of figuring out what they’re like and how they came to be.”
This finding supports growing evidence that supermassive black holes may explain why Little Red Dots appear so bright at such an early stage in cosmic history—an era when large numbers of stars were unlikely.
Black holes emit significant energy because they compress and heat material as it falls inward. Confirming one in CAPERS-LRD-z9 demonstrates this relationship between supermassive black holes and Little Red Dots.
The research also addresses why these galaxies are so red; it may be due to thick clouds of gas around their central black holes altering how light passes through them. “We’ve seen these clouds in other galaxies,” explained Taylor. “When we compared this object to those other sources, it was a dead ringer.”
The size of this newly discovered black hole is notable: up to 300 million times more massive than our sun—about half as massive as all stars within its host galaxy combined.
Identifying such a large black hole so soon after the Big Bang gives astronomers new opportunities to study how these objects form and grow over time. Black holes that formed later had more chances to increase their mass; those present shortly after cosmic dawn did not. “This adds to growing evidence that early black holes grew much faster than we thought possible,” said Finkelstein. “Or they started out far more massive than our models predict.”
Researchers plan further observations using JWST for higher-resolution data on CAPERS-LRD-z9’s properties and evolution. “This is a good test object for us,” said Taylor. “We haven’t been able to study early black hole evolution until recently, and we are excited to see what we can learn from this unique object.”
Additional information for this research came from observations using the Dark Energy Spectroscopic Instrument (DESI) at Kitt Peak National Observatory under NSF NOIRLab programs.
