Simulation of quasar merger. Source: DOI 10.3847/2041-8213/aca160

Ultramassive black holes with extreme masses of more than 50 billion solar masses can form in the rare events of multiple quasar mergers that occurred about 11 billion years ago, according to new research by astrophysicists at the Harvard-Smithsonian Center for Astrophysics. , Carnegie Mellon University and the University of California at Riverside .

We found that one possible channel for the formation of ultramassive black holes is from the extreme merger of massive galaxies that is most likely to occur at the epoch of cosmic noon,” says first author Dr. Yueying Ni, a Harvard Center researcher. -Smithsonian School of Astrophysics and Carnegie Mellon University. Working hand in hand with data from telescopes, computer simulations help astrophysicists fill in the missing pieces about 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 is the largest simulation in terms of particle charge or memory in the field of galaxy formation simulations.

Astrid’s scientific goal is to study galaxy formation, supermassive black hole coalescence, and reionization throughout cosmic history,” explained Dr. Ni. Astrid models large volumes of the cosmos spanning hundreds of millions of light-years, but she can magnify them with very high resolution. The authors developed Astrid using the Frontera supercomputer at the Texas Advanced Computing Center. “Frontera is the only system we’ve run Astrid on from day one. It’s a pure Frontera-based simulation,” said Dr. Ni.

The team’s findings from Astrid’s simulations show something completely mind-boggling: Black hole formation can reach a theoretical upper limit of 10 billion solar masses.

It is a very difficult task from the computational point of view. But you can only capture these rare and extreme objects with a high-volume simulation,” said Dr. Ni. “What we found are three ultramassive black holes that gathered their mass during cosmic noon, the time 11 billion years ago when star formation, active galactic nuclei (AGNs), and supermassive black holes in general are at their maximum. activity”. “About half of all the stars in the Universe were born during cosmic noon.”

Evidence for this comes from multi-wavelength data from numerous galaxy surveys, such as the Great Observatories Origins Deep Survey, where the spectra of distant galaxies tell us about the ages of their stars, their star formation history, and their history. the chemical elements of the stars they contain.” “At this time we detected an extreme and relatively rapid merger of three massive galaxies”.

Each of the galaxies’ masses is 10 times the mass of our own Milky Way, and a supermassive black hole sits at the center of each galaxy.” “Our findings show the possibility that these quasar triplet systems are the progenitors of those rare ultramassive black holes, after those triplets gravitationally interact and merge with each other.”

Sources, credits and references: Yueying Ni et al, Ultramassive Black Holes Formed by Triple Quasar Mergers at z ∼ 2, The Astrophysical Journal Letters (2022). DOI: 10.3847/2041-8213/aca160 .