Ultramassive black holes with extreme masses of over 50 billion solar masses can be formed in the rare events that are multiple quasar mergers happening around 11 billion years ago, according to new research by astrophysicists from the Harvard-Smithsonian Center for Astrophysics, Carnegie Mellon University and the University of California, Riverside.
Illustration of the quasar triplet system and its environment. Image credit: Ni et al., doi: 10.3847/2041-8213/aca160.
“We found that one possible formation channel for ultramassive black holes is from the extreme merger of massive galaxies that are most likely to happen in the epoch of the cosmic noon,” said first author Dr. Yueying Ni, a researcher at the Harvard-Smithsonian Center for Astrophysics and Carnegie Mellon University.
Working hand-in-hand with telescope data, computational simulations help astrophysicists fill in the missing pieces on the origins of stars and exotic objects like black holes.
One of the largest cosmological simulations to date is called Astrid, developed by Dr. Ni and colleagues.
It’s the largest simulation in terms of the particle, or memory load in the field of galaxy formation simulations.
“The science goal of Astrid is to study galaxy formation, the coalescence of supermassive black holes, and re-ionization over the cosmic history,” Dr. Ni said.
Astrid models large volumes of the cosmos spanning hundreds of millions of light years, yet can zoom in to very high resolution.
The authors developed Astrid using the Frontera supercomputer at the Texas Advanced Computing Center.
“Frontera is the only system that we performed Astrid from day one. It’s a pure Frontera-based simulation,” Dr. Ni said.
The team’s findings from the Astrid simulations show something completely mind-boggling — the formation of black holes can reach a theoretical upper limit of 10 billion solar masses.
“It’s a very computational challenging task. But you can only catch these rare and extreme objects with a large volume simulation,” Dr. Ni said.
“What we found are three ultramassive black holes that assembled their mass during the cosmic noon, the time 11 billion years ago when star formation, active galactic nuclei (AGN), and supermassive black holes in general reach their peak activity.”
“About half of all the stars in the Universe were born during cosmic noon.”
“Evidence for it comes from multi wavelength data of numerous galaxy surveys such as the Great Observatories Origins Deep Survey, where the spectra from distant galaxies tell about the ages of its stars, its star formation history, and the chemical elements of the stars within.”
“In this epoch we spotted an extreme and relatively fast merger of three massive galaxies.”
“Each of the galaxy masses is 10 times the mass of our own Milky Way, and a supermassive black hole sits in the center of each galaxy.”
“Our findings show the possibility that these quasar triplet systems are the progenitor of those rare ultramassive black holes, after those triplets gravitationally interact and merge with each other.”
The study appears in the Astrophysical Journal.
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Yueying Ni et al. 2023. Ultramassive Black Holes Formed by Triple Quasar Mergers at z ~ 2. ApJL 940, L49; doi: 10.3847/2041-8213/aca160
