The ASTRID cosmological simulation, a massive simulation run on TACC’s Frontera supercomputer, is aiding in the investigation of ultra-massive black holes.
Ultra-massive black holes are the heaviest entities in the cosmos, with some weighing in at millions or even billions of times the mass of the Sun. Through simulations run on TACC’s Frontera supercomputer, astrophysicists have gained insight into the origin of these behemoth black holes, which formed around 11 billion years ago.
“We found that one possible formation channel for ultra-masssive black holes is from the extreme merger of massive galaxies that are most likely to happen in the epoch of the ‘cosmic noon,” said Yueying Ni, a postdoctoral fellow at the Harvard–Smithsonian Center for Astrophysics.
Ni is the lead author of work published in The
One of the largest cosmological simulations to date is called Astrid, co-developed by Ni. 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,” she explained. Astrid models large volumes of the cosmos spanning hundreds of millions of light years, yet can zoom in to very high resolution.
Ni developed Astrid using the Texas Advanced Computing Center’s (TACC) Frontera supercomputer, the most powerful academic supercomputer in the U.S., funded by the National Science Foundation(NSF).
”Frontera is the only system that we performed Astrid from day one. It’s a pure Frontera-based simulation,” Ni continued.
Frontera is ideal for Ni’s Astrid simulations because of its capability to support large applications that need thousands of compute nodes, the individual physical systems of processors and memory that are harnessed together for some of science’s toughest computations.
”We used 2,048 nodes, the maximum allowable in the large queue, to launch this simulation on a routine basis. It’s only possible on large supercomputers like Frontera,” Ni said.
Her 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 computationally challenging task. But you can only catch these rare and extreme objects with a large volume simulation,” Ni said.
“What we found are three ultra-massive 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,” she added.
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,” Ni said. “Each of the galaxy masses is 10 times the mass of our own
“We’re pursuing a mock-up of observations for JWST data from the Astrid simulation,” Ni said.
“In addition, the future space-based
Reference: “Ultramassive Black Holes Formed by Triple Quasar Mergers at z ∼ 2” by Yueying Ni, Tiziana Di Matteo, Nianyi Chen, Rupert Croft and Simeon Bird, 30 November 2022, The DOI: 10.3847/2041-8213/aca160
The study was funded by the National Science Foundation and the National Aeronautics and Space Administration.