Astronomers unravel formation of black holes so massive they shouldn’t exist

The merger of massive galaxies could be why ultra-massive black holes have formed, according to a new study.

Supercomputer simulations were used to shed light on the origin of some of the most massive objects in the universe that were formed about 11 billion years ago, said the research, published recently in The Astrophysical Journal Letters.

Such massive black holes – which can reach millions and billions of times the mass of the Sun – can form the extremely rare merger of triple quasars, explained scientists from the University of Texas at Austin.

Quasars are extremely bright and powerful energy sources at the heart of galaxies that are thought to be powered by black holes.

A single such entity is known to be over thousand times brighter than an entire galaxy and in the even rarer multiple quasar systems, the bodies are held together by gravity and are likely the product of galaxies colliding, scientists said.

“We found that one possible formation channel for ultra-massive black holes is from the extreme merger of massive galaxies that are most likely to happen in the epoch of the ‘cosmic noon’,” study co-author Yueying Ni said in a statement.

Researchers found the formation of black holes can reach a theoretical upper limit of 10 billion solar masses using advanced supercomputer simulations.

“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 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.

Astronomers said half of all the stars in the universe were born during cosmic noon based on numerous galaxy surveys.

“In this epoch we spotted an extreme and relatively fast merger of three massive galaxies,” Dr Ni said.

“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 ultra-massive blackholes, after those triplets gravitationally interact and merge with each other,” she said.

Researchers suspect future observations of galaxies at the “cosmic noon” can help unveil how supermassive black holes coalesce to form ultra-massive ones.

“This is an exciting time for astrophysicists, and it’s good that we can have simulation to allow theoretical predictions for those observations,” Dr Ni added.

“It’s great to have access to supercomputers, technology that allow us to model a patch of the universe in great detail and make predictions from the observations,” she added.