Nav: Home

Clandestine black hole may represent new population

June 27, 2016

For about two decades, astronomers have known about an object called VLA J213002.08+120904 (VLA J2130+12 for short). Although it is close to the line of sight to the globular cluster M15, most astronomers had thought that this source of bright radio waves was probably a distant galaxy.

Thanks to recent distance measurements with an international network of radio telescopes, including the EVN (European Very Long Baseline Interferometry Network) telescopes, the NSF's Green Bank Telescope and Arecibo Observatory, astronomers realized that VLA J2130+12 is at a distance of 7,200 light years, showing that it is well within our own Milky Way galaxy and about five times closer than M15. A deep image from Chandra reveals it can only be giving off a very small amount of X-rays, while recent VLA data indicates the source remains bright in radio waves.

This new study indicates that VLA J2130+12 is a black hole a few times the mass of our Sun that is very slowly pulling in material from a companion star. At this paltry feeding rate, VLA J2130+12 was not previously flagged as a black hole since it lacks some of the telltale signs that black holes in binaries typically display.

"Usually, we find black holes when they are pulling in lots of material. Before falling into the black hole this material gets very hot and emits brightly in X-rays," said Bailey Tetarenko of the University of Alberta, Canada, who led the study. "This one is so quiet that it's practically a stealth black hole."

This is the first time a black hole binary system outside of a globular cluster has been initially discovered while it is in such a quiet state.

Hubble observations identified VLA J2130+12 with a star having only about one-tenth to one-fifth the mass of the Sun. The observed radio brightness and the limit on the X-ray brightness from Chandra allowed the researchers to rule out other possible interpretations, such as an ultra-cool dwarf star, a neutron star, or a white dwarf pulling material away from a companion star.

Because this study only covered a very small patch of sky, the implication is that there should be many of these quiet black holes around the Milky Way. The estimates are that tens of thousands to millions of these black holes could exist within our Galaxy, about three to thousands of times as many as previous studies have suggested.

"Unless we were incredibly lucky to find one source like this in a small patch of the sky, there must be many more of these black hole binaries in our Galaxy than we used to think," said co-author Arash Bahramian, also of the University of Alberta.

There are other implications of finding that VLA J2130+12 is relatively near to us.

"Some of these undiscovered black holes could be closer to the Earth than we previously thought," said Robin Arnason, a co-author from Western University, Canada "However there's no need to worry as even these black holes would still be many light years away from Earth."

Sensitive radio and X-ray surveys covering large regions of the sky will need to be performed to uncover more of this missing population.

If, like many others, this black hole was formed in the plane of the Milky Way's disk, it would have needed a large kick at birth to launch it to its current position about 3,000 light years above the plane of the Galaxy.
These results appear in a paper in The Astrophysical Journal. NASA's Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra's science and flight operations.


Dr James Miller-Jones
ICRAR-Curtin University, research co-author

Kirsten Gottschalk
ICRAR media contact

Megan Watzke
Chandra X-ray Center, Cambridge, Mass.

International Centre for Radio Astronomy Research

Related Black Hole Articles:

Scientists make waves with black hole research
Scientists at the University of Nottingham have made a significant leap forward in understanding the workings of one of the mysteries of the universe.
Collapsing star gives birth to a black hole
Astronomers have watched as a massive, dying star was likely reborn as a black hole.
When helium behaves like a black hole
A team of scientists has discovered that a law controlling the bizarre behavior of black holes out in space -- is also true for cold helium atoms that can be studied in laboratories.
Star in closest orbit ever seen around black hole
Astronomers have found evidence of a star that whips around a likely black hole twice an hour.
Tail of stray black hole hiding in the Milky Way
By analyzing the gas motion of an extraordinarily fast-moving cosmic cloud in a corner of the Milky Way, Astronomers found hints of a wandering black hole hidden in the cloud.
Hubble gazes into a black hole of puzzling lightness
The beautiful spiral galaxy visible in the center of the image is known as RX J1140.1+0307, a galaxy in the Virgo constellation imaged by the NASA/ESA Hubble Space Telescope, and it presents an interesting puzzle.
Clandestine black hole may represent new population
Astronomers have combined data from NASA's Chandra X-ray Observatory, the Hubble Space Telescope and the National Science Foundation's Karl G.
When will a neutron star collapse to a black hole?
Astrophysicists from Goethe-University Frankfurt have found a simple formula for the maximum mass of a rotating neutron star and hence answered a question that had been open for decades.
Behemoth black hole found in an unlikely place
Astronomers have uncovered a near-record breaking supermassive black hole, weighing 17 billion suns, in an unlikely place: in the center of a galaxy in a sparsely populated area of the universe.
Behemoth black hole found in an unlikely place
Astronomers have uncovered one of the biggest supermassive black holes, with the mass of 17 billion Suns, in an unlikely place: the centre of a galaxy that lies in a quiet backwater of the Universe.

Related Black Hole Reading:

Best Science Podcasts 2018

We have hand picked the best science podcasts for 2018. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

The Person You Become
Over the course of our lives, we shed parts of our old selves, embrace new ones, and redefine who we are. This hour, TED speakers explore ideas about the experiences that shape the person we become. Guests include aerobatics pilot and public speaker Janine Shepherd, writers Roxane Gay and Taiye Selasi, activist Jackson Bird, and fashion executive Kaustav Dey.
Now Playing: Science for the People

#479 Garden of Marvels (Rebroadcast)
This week we're learning about botany and the colorful science of gardening. Author Ruth Kassinger joins us to discuss her book "A Garden of Marvels: How We Discovered that Flowers Have Sex, Leaves Eat Air, and Other Secrets of the Way Plants Work." And we'll speak to NASA researcher Gioia Massa about her work to solve the technical challenges of gardening in space.