The second image of the first black hole ever captured by humanity shows that its shadow lasts for a year.
The newly released image of the supermassive black hole at the heart of the galaxy Messier 87 (M87) was captured by the Event Horizon Telescope (EHT) on April 21, 2018, a year and 10 days after it was first captured.
Just like in the image taken in April 2017, this second image of the supermassive black hole, known as M87*, shows a glowing golden ring representing the material orbiting the black hole being heated to extreme temperatures. There is still a dark shadow at the heart of this ring, as predicted by Einstein’s theory of gravity in 1915, known as general relativity.
“One of the basic requirements of science is to be able to reproduce the results,” Keiichi Asada, an associate research fellow at the Academia Sinica Institute for Astronomy and Astrophysics, said in a statement. “Confirming the existence of the ring in a brand-new data set is a major milestone for our collaboration and a strong indicator that we are looking at the shadow of the black hole and the material orbiting around it.”
Related: The first black hole ever imaged by humans contains twisted magnetic fields and scientists are thrilled
The new image of this supermassive black hole confirms the accuracy of this theory of gravity, which predicts that the width of M87* should remain the same as long as its mass does not change significantly, confirming that the radius of the black hole is indeed related to its mass.
The image also confirms the occurrence of some changes in the brightness of the disk, which are related to the disturbance in the matter around the black hole and its gradual feeding.
M87* in 2017 and 2018: What has changed and what has stayed the same?
The M87* supermassive black hole is located 55 million light-years from Earth in the heart of the M87 galaxy, and its mass is equivalent to about 6.5 billion suns.
M87* powers the core of an active elliptical galaxy and a bright galactic nucleus as it gradually feeds on the matter around it, heating up what it doesn’t consume with powerful magnetic fields that transport the material to its poles before blasting it away at near the speed of light. .
M87* made history when it was first imaged by the EHT on April 11, 2017. Additional data analysis of the M87* EHT image showed how light was polarized around the black hole, giving hints about the structure of the magnetic fields fired by the jets and the nature of the hot gas, or plasma. , surrounding the supermassive black hole.
Images of M87* from 2017 and 2018 are remarkably similar, with the bright rings around the supermassive black hole remaining the same size.
This is an important observation because it shows that because the mass of this supermassive black hole has not changed significantly, nor has the diameter of its outer layer, a surface that traps light is called the event horizon which acts as the outer boundary of the black hole. slot. This helps confirm the suggestion from general relativity that the diameter of a black hole depends on its mass.
“One of the fascinating properties of a black hole is that its radius strongly depends on just one quantity: its mass,” said Nitika Yadlapalli York, a scientist at NASA’s Jet Propulsion Laboratory. “Since M87* is not accreting matter (which would increase its mass) at a rapid rate, general relativity tells us that its radius will remain more or less unchanged over the course of human history. It is very exciting to see that our data confirm this prediction.”
Scientists expect that the M87* black hole is not accumulating matter fast enough for its growth to be noticeable over a human lifetime, and this new image also helps confirm that this may be the case.
However, this does not mean that nothing has changed for the M87* between EHT close-ups. In the new image, the brightest top of the ring around the black hole has moved 30 degrees counterclockwise. This is something the EHT team was expecting to see and confirms the variability of turbulent matter around the black hole.
“The biggest change in peak brightness around the ring is actually something we expected when we published the first results in 2019,” said Brett Jeter, a postdoctoral fellow at the Academia Sineca Institute for Astronomy. “While general relativity says the size of the ring should remain more or less constant, emission from the turbulent, chaotic accretion disk around the black hole will cause the brightest part of the ring to wobble around a common center.
“The amount of fluctuation we see over time is something we can use to test our theories about the magnetic field and plasma environment around the black hole.”
What’s next for the supermassive black hole M87*?
The first image of M87* and in-depth analysis of the data used to construct it began a new era of black hole investigation, and also gave scientists a new laboratory to test general relativity.
The next step in these investigations was to collect repeated observations of this supermassive black hole, with this new image representing the first use of data collected from M87* after 2017 by the EHT.
Help was provided to EHT to collect new and improved images of M87* In 2018, five months after its construction was completed in the Arctic Circle, the Greenland Telescope joined other antennas in the array that makes up this Earth-sized telescope. This improved the EHT’s image resolution and sky coverage, especially from north to south.
Repeated observations of M87* have also allowed the EHT to be used to test cutting-edge developments in an astronomical technique called high-frequency radio interferometry and autonomous imaging and modeling techniques.
“The inclusion of the Greenland Telescope in our array fills critical gaps in our Earth-sized telescope,” said Rohan Dahalli, a doctoral candidate at the Institute of Astrophysics of Andalusia. “The inclusion of the Greenland Telescope in our array has filled critical gaps in our Earth-sized telescope.”
The EHT team has continued to monitor M87* after 2018, with further observations in 2021 and 2022, and with the next observation of M87* by the EHT planned for the first half of this year.
The only thing astronomers hope to see in observations after 2018 is a stream of material emerging from M87*, something the EHT array was not advanced enough to see 6 years ago.
“The upcoming 2021, 2022 and 2024 observations see improvements in the array, increasing our enthusiasm to push the limits of black hole astrophysics,” Dahaly concluded.
The team’s research and new images of M87* have been published in the journal Astronomy & Astrophysics.