An enormous object known as Sagittarius A* is located close to the Milky Way’s center. This “supermassive” black hole is not the only one that may have expanded alongside our galaxy. Behemoths of a similar size are thought to be at the center of nearly all large galaxies in the universe, according to researchers.
Joseph Simon, a postdoctoral researcher at the University of Colorado Boulder’s Department of Astrophysical and Planetary Science, said that some can get really big.
“We also see others that we think are billions of times the mass of the sun,” he said. “The black hole at the center of our galaxy is millions of times the mass of the sun.”
The astrophysicist has devoted his vocation to concentrating on the way these hard-to-notice objects behave. A mathematical concept known as the black hole mass function was used by him in a recent study to predict the masses of the universe’s largest supermassive black holes using computer simulations, or “models.”
To put it another way, Simon wanted to know what you might find if you could massively expand each of these black holes one at a time.
His computations suggest that billions of years prior, dark openings might have been significantly greater than researchers once thought. The forces that shaped objects like Sagittarius A* as they evolved from small black holes into the giants that they are today may be clarified by the findings, which could help researchers solve an even larger mystery.
Simon stated, “We’re starting to see from a variety of different sources that there have been pretty huge things in the universe since pretty early on.”
He distributed his discoveries on May 30 in The Astrophysical Diary Letters.
Galactic symphony
For Simon, those “pretty monstrous things” are his meat and potatoes.
The astrophysicist is a member of the North American Nanohertz Observatory for Gravitational Waves (NANOGrav), which is a second research endeavor. Simon and hundreds of other scientists from the United States and Canada have been looking for a phenomenon called the “gravitational wave background” for 15 years as part of the project. The idea is based on the near-constant flow of gravitational waves, which are enormous ripples in space and time that move through the universe.
Supermassive black holes are also to blame for the origins of this cosmic churn. Simon explained that the central black holes of two galaxies may also collide or even merge if they collide in space. They turn around and around before colliding like two cymbals in an orchestra—only this collision produces gravitational waves that literally warp the universe’s fabric.
However, scientists must first determine the actual size of the universe’s supermassive black holes in order to comprehend the background of the gravitational waves. Simon asserted that larger cymbals produce significantly larger gravitational waves and a louder bang.
There is only one issue.
He stated, “We have really good measurements for the masses of the supermassive black holes for both our own galaxy and galaxies close by.” These measurements are not available for galaxies further away. We can only guess.”
In his new research, Simon made the decision to guess in a completely new way.
He began by compiling data on hundreds of thousands of galaxies, some of which were billions of years old. Since light can only travel so fast, when we look at galaxies further away, we are looking back in time. Simon used that information to estimate the black hole masses of the universe’s largest galaxies. He then used computer models to simulate the gravitational wave background that could be produced by these galaxies and that currently covers Earth.
The entire universe’s supply of supermassive black hole masses, dating back roughly 4 billion years, is revealed by Simon’s findings. Additionally, he noticed an oddity: Compared to what some previous studies had predicted, there appeared to have been a lot more massive galaxies spread out across the universe billions of years ago. That made little sense.
Simon stated, “There has been the expectation that you would only see these really massive systems in the nearby universe.” The expansion of black holes takes time.
However, his research adds to the growing body of evidence that suggests they might not require as much time as astrophysicists previously thought. For instance, the NANOGrav team has observed similar hints of massive black holes that once existed billions of years ago.
Until further notice, Simon is expecting to investigate the full scope of dark openings broadening significantly farther back in time, uncovering hints about how the Smooth Way World and, in the long run, our own planetary group appeared.
Simon stated, “Understanding the masses of black holes is critical to some of these foundational questions, such as the background of gravitational waves, as well as how galaxies grow and how our universe has evolved.”
More information: Joseph Simon, Exploring Proxies for the Supermassive Black Hole Mass Function: Implications for Pulsar Timing Arrays, The Astrophysical Journal Letters (2023). DOI: 10.3847/2041-8213/acd18e
