New data from a powerful NASA telescope has discovered the spin rate of a supermassive black hole, showing that it’s moving “almost as fast as Einstein’s theory of gravity will allow.”
NASA’s Nuclear Spectroscopic Telescope Array (NuSTAR) and the European Union’s XMM-Newton telescope tracked the supermassive black hole at the centre of galaxy NGC 1365. The black hole is several million times larger than our sun.
“This is hugely important to the field of black hole science,” Lou Kaluzienski, a NuSTAR program scientist said in a release.
The data, presented on Thursday in Nature shows that the black hole at the heart of NGC 1365 was spinning at 1.08 billion kilometres per hour.
The scientists say that knowing the speed that this is happening means that they can discover potentially new things about the nature of the universe and test Einstein’s theory of relativity.
“We can trace matter as it swirls into a black hole using X-rays emitted from regions very close to the black hole,” NuSTAR principal investigator Fiona Harrison said in the same release. “The radiation we see is warped and distorted by the motions of particles and the black hole’s incredibly strong gravity.”
The amount of spin that the black hole has is key to learning the past of the particular galaxy and the universe in general, the scientists say.
“These monsters, with masses from millions to billions of times that of the sun, are formed as small seeds in the early universe and grow by swallowing stars and gas in their host galaxies, merging with other giant black holes when galaxies collide, or both,” The study’s lead author, Guido Risaliti said in the release.
The new measurements of the black hole’s spin can be captured mostly because of the different wavelengths exposed by NASA’s NuSTAR telescope combined with the wave lengths of the XMM-Newton. Before, clouds of gas were obscuring the black hole, but the combined efforts of both telescopes cut through interference.
“If I could have added one instrument to XMM-Newton, it would have been a telescope like NuSTAR,” Norbert Schartel, XMM-Newton Project Scientist said in a release. “The high-energy X-rays provided an essential missing puzzle piece for solving this problem.”
The NuSTAR was launched in 2012 while the XMM-Newton was launched in 1999.
EXPLANATION OF THE ABOVE DIAGRAM FROM NASA
Scientists measure the spin rates of supermassive black holes by spreading the X-ray light into different colors. The light comes from accretion disks that swirl around black holes, as shown in both of the artist’s concepts. They use X-ray space telescopes to study these colors, and, in particular, look for a “fingerprint” of iron — the peak shown in both graphs, or spectra — to see how sharp it is. Prior to observations with NASA’s Spectroscopic Telescope Array, or NuSTAR, and the European Space Agency’s XMM-Newton telescope, there were two competing models to explain why this peak might not appear to be sharp.
The “rotation” model shown at top held that the iron feature was being spread out by distorting effects caused by the immense gravity of the black hole. If this model were correct, then the amount of distortion seen in the iron feature should reveal the spin rate of the black hole.
The alternate model held that obscuring clouds lying near the black hole were making the iron line appear artificially distorted. If this model were correct, the data could not be used to measure black hole spin.
NuSTAR helped to solve the case, ruling out the alternate “obscuring cloud” model. Its high-energy X-ray data — shown at top as green bump to the right of the peak — revealed that features in the X-ray spectrum are in fact coming from the accretion disk and not from the obscuring clouds. Together with XMM-Newton, the space observatories were able to make the first conclusive measurement of a black hole’s spin rate, and more generally, confirm that the “gravitational distortion” model is accurate.
- NASA Supermassive-Black-Hole Gravity Discovery: “Confirms Einstein’s Theory of Space-Time” (dailygalaxy.com)
- Spinning Black Hole Observed for the First Time (news.discovery.com)
- Black holes: How heavy and how! – Part II (thehindu.com)
- Black hole’s super-fast spin revealed – NBCNews.com (blog) (science.nbcnews.com)
- NuSTAR helps solve riddle of black hole spin (rdmag.com)
- Black hole’s super-fast spin revealed (science.nbcnews.com)
- Astronomers Spot Black Hole Spinning Near the Speed of Light (escapistmagazine.com)
- NASA to Livestream Black Hole Observations Wednesday (dailygalaxy.com)
- NASA’s NuSTAR Helps Solve Riddle of Black Hole Spin (spacefellowship.com)