Posted on May 12, 2021 in Black Holes, Milky Way Galaxy, Science
Astronomers are beginning to understand what happens when black holes get the urge to roam through the Milky Way. Typically, a supermassive black hole (SMBH) exists at the core of a massive galaxy. But sometimes SMBHs may “wander” throughout their host galaxy, remaining far from the center in regions such as the stellar halo, a nearly spherical area of stars and gas that surrounds the main section of the galaxy.
May Impact Our Solar System Every 100 Billion Years
“It is extremely unlikely that any wandering supermassive black hole will come close enough to our Sun to have any impact on our solar system,” said lead author Michael Tremmel, a postdoctoral fellow at the Yale Center for Astronomy and Astrophysics. “We estimate that a close approach of one of these wanderers that is able to affect our solar system should occur every 100 billion years or so, or nearly 10 times the age of the universe.”
“Up to Thousands of Years” –Circuits of Stars Orbiting Supermassive Black Holes
“Over the last few years I’ve been excited about a growing number of detections of luminous sources that are set off from the centers of their galaxies,” wrote Tremmel in an email to The Daily Galaxy. “For example, in 2019 astronomers created a catalog of objects that are called hyperluminous x-ray sources, which are potential candidates for supermassive black holes. In 2020, discoveries showed radio sources consistent with supermassive black holes in dwarf galaxies.”
We’re Still Only Scratching the Surface
“Our ability to find low luminosity sources is getting better, as is our ability to detect the presence of multiple closeby sources, so-called Dual Active Galactic Nuclei,” Tremmel wrote in his email. “There is also progress in finding black holes through dynamical measurements (i.e. measuring the motions of nearby stars for their gravitational influence). These are SMBHs in the centers of what are thought to be the core remnants of a once much larger galaxy. It is important to note that all of these detections are in other galaxies and not the Milky Way specifically.”
“At the Edge of Spacetime” –Strange Star S2 Orbiting Milky Way’s Supermassive Black Hole
“Put together,’ Tremmel wrote, “these observations speak to the fact that SMBHs far from the galactic centers are likely a common occurrence, though we are still only scratching the surface.”
Astronomers theorize that this phenomenon often occurs as a result of mergers between galaxies. A smaller galaxy will join with a larger, main galaxy, depositing its own, central SMBH onto a wide orbit within the new host.
Milky Way Should Host Several Supermassive Black Holes –All Invisible
In the 2018 study published in the Astrophysical Journal Letters, researchers from Yale, the University of Washington, Institut d’Astrophysique de Paris, and University College London predict that galaxies with a mass similar to the Milky Way should host several supermassive black holes. The team used a new, state-of-the-art cosmological simulation, Romulus, to predict the dynamics of SMBHs within galaxies with better accuracy than previous simulation programs.
Tremmel said that since wandering SMBHs are predicted to exist far from the centers of galaxies and outside of galactic disks, they are unlikely to accrete more gas—making them effectively invisible. “We are currently working to better quantify how we might be able to infer their presence indirectly,” Tremmel said.
Maxwell Moe, astrophysicist, NASA Einstein Fellow, University of Arizona via Yale University
Image credit: Shutterstock License
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Astronomers are beginning to understand what happens when black holes get the urge to roam through the Milky Way. Typically, a supermassive black hole (SMBH) exists at the core of a massive galaxy. But sometimes SMBHs may “wander” throughout their host galaxy, remaining far from the center in regions such as the stellar halo, a nearly spherical area of stars and gas that surrounds the main section of the galaxy.
Astronomers theorize that this phenomenon often occurs as a result of mergers between galaxies in an expanding universe. A smaller galaxy will join with a larger, main galaxy, depositing its own, central SMBH onto a wide orbit within the new host.
“What Have They Found?” ESO to Reveal Epic Black-Hole Discovery
“It is extremely unlikely that any wandering supermassive black hole will come close enough to our Sun to have any impact on our solar system,” said lead author Michael Tremmel, a postdoctoral fellow at the Yale Center for Astronomy and Astrophysics. “We estimate that a close approach of one of these wanderers that is able to affect our solar system should occur every 100 billion years or so, or nearly 10 times the age of the universe.”
In the 2018 study published in the Astrophysical Journal Letters, researchers from Yale, the University of Washington, Institut d’Astrophysique de Paris, and University College London predict that galaxies with a mass similar to the Milky Way should host several supermassive black holes. The team used a new, state-of-the-art cosmological simulation, Romulus, to predict the dynamics of SMBHs within galaxies with better accuracy than previous simulation programs.
“Antarctica Alert” –Ghostly Supermassive Black Hole Invader Detected
Tremmel said that since wandering SMBHs are predicted to exist far from the centers of galaxies and outside of galactic disks, they are unlikely to accrete more gas—making them effectively invisible. “We are currently working to better quantify how we might be able to infer their presence indirectly,” Tremmel said.
“Attempt No Voyage Here!” Milky Way Harbors 100 Million Black Holes –‘There are Tens of Millions of these Dark Enigmatic Objects Each the Size of 30 Suns’ (Today’s Most Popular)
On March 9th, we reported that after conducting a cosmic inventory to calculate and categorize stellar-remnant black holes, astronomers from the University of California concluded that there are probably tens of millions of the enigmatic, dark objects in the Milky Way – far more than expected.
In stark contrast to the predictions of the Yale team, is physicist George Chapline’s conjecture that there has never been direct evidence of a central black hole,” while acknowledging there are objects that general relativity would predict are black holes at the centers of galaxies. “Ironically, Einstein also didn’t believe in black holes even though he created general relativity.”
Compared to the supermassive black holes in the centers of other galaxies, our black hole, Sagittarius A*, is strangely quiet. But Chapline thinks it’s more than quiet: he predicts that we’ll soon find that it does not exist.
Chapline, at the Lawrence Berkeley National Laboratory, expects to have his prediction that black holes don’t exist confirmed with the release of findings by the Event Horizon Telescope—really a virtual telescope with an effective diameter of the Earth—that has been pointing at the Milky Way’s central supermassive black hole for the last several years.
The Daily Galaxy, Max Goldberg, via Yale University
Maxwell Moe, astrophysicist, NASA Einstein Fellow, University of Arizona. Max can be found two nights a week probing the mysteries of the Universe at the Kitt Peak National Observatory. Max received his Ph.D in astronomy from Harvard University in 2015.