The first ever image of a supermassive black hole was announced on April 10th, 2019. The black hole at the center of the M87 galaxy was shown in the image. There is a person named Virgo A. They obtained an image of the core region of the Centaurus A galaxy in 2021. The European Southern Observatory (ESO) announced earlier this month that it would be sharing the results from its latest campaign.
The black hole is 44 million km from Earth and has a mass of 4.31 million Suns. The results of the campaign were shared in a press release and live-streamed in a series of press conferences. The results were published in a special issue of The Astrophysical Journal Letters.
Astronomers theorize about the existence of SMBHs, which were believed to be the reason for the energetic core regions of massive galaxies. These regions are known to temporarily outshine all of the stars in their disks. The jets of superheated material have been found at a fraction of the speed of light.
Astronomers have been able to test the laws of physics under the most extreme conditions thanks to the study of SMBHs. The study of these massive black holes used to be limited to observing their effect on the environment. Gas and dust fall in around the outer edges of the SMBHs because of the gravitational forces of the SMBHs.
The matter is accelerated to a high rate of speed and then released a lot of energy into the black hole. It is difficult to see these massive objects in telescopes because they are located in the center of a tightly packed group of stars.
A virtual telescope with an equivalent size to the Earth was created thanks to a technique known as Very Long Baseline Interferometry. This telescope can gather light over time and reconstruct an image of what it looks like, similar to a long exposure time with a camera.
The bright event horizon around the M87 black hole was the first to be imaged by the EHT team. The latest image shows the event horizon of Sagittarius A* (Sgr A* for short) and is the first definitive evidence of this.
The size of the ring was agreed with predictions from Einstein, according to a press release from the Institute of Astronomy and Astrophysics.
The ALMA and APEX are in northern Chile and are part of the EHT Collaboration. The director general of the observatory expressed his support for the Collaboration and its results at the press conference.
He said that it was exciting to have been playing an important role in unraveling the mysteries of black holes and Sgr A*.
There are some differences between Sagittarius A* and M87*. Our galaxy's SMBH is a thousand times smaller and less massive than the Sun. The team concludes that the edges of both black holes look the same, which is the result of General Relativity governing these objects up close. Differences seen further away are due to differences in the material surrounding them.
Sgr A* was more difficult to image than M87. Chi-kwan Chan is a scientist from the University of Arizona Data Science Institute.
“The gas in the vicinity of the black holes moves at the same speed – nearly as fast as light – around both Sgr A* and M87*. But where gas takes days to weeks to orbit the larger M87*, in the much smaller Sgr A* it completes an orbit in mere minutes. This means the brightness and pattern of the gas around Sgr A* were changing rapidly as the EHT Collaboration was observing it – a bit like trying to take a clear picture of a puppy quickly chasing its tail.”
M87* was a steadier target than Sgr A*, because it had a rapid speed that made the images look the same. The images of Sgr A* were different due to the slower speed of the accretion disk. The researchers had to develop new tools to account for this and give an average of all the different images.
The team worked for five years to combine and analyze their data and create an unprecedented library of black holes to compare with the observations. Scientists will now have images of two black holes with different sizes and offers, which will allow them to test the laws of physics in different ways. The data will be used to test theories and models of how gas behaves.
This process is thought to play a key role in the formation and evolution of galaxies. Keiichi Asada is a scientist from the Institute of Astronomy and Astrophysics in Taiwan.
“Now we can study the differences between these two supermassive black holes to gain valuable new clues about how this important process works. We have images for two black holes – one at the large end and one at the small end of supermassive black holes in the Universe – so we can go a lot further in testing how gravity behaves in these extreme environments than ever before.”
The results of the observation campaign were included in a special issue of The Astrophysical Journal Letters. Papers II, III, and IV show how the lower mass and shorter scale of Sgr A* led to complexity with the data analysis. Researchers combine the EHT results with multi-wavelength constraints to explore the accretion and outflow physics of Sgr A*.
In Paper VI, researchers show how to measure the mass, distance, and ring diameter of Sgr A* with a 1% accuracy. There are additional papers not performed by the EHT collaboration that address the possibility of black hole images, a new analysis of the data obtained by the campaign, and black hole image reconstruction.
Thanks to over 300 scientists and 80 institutions worldwide, these results were possible. The ARO Submillimeter Telescope is located on the summit of the Kitt Peak National Observatory.
The South Pole Telescope is located at the Amundsen South Pole Station and the Institute Radioastronomie Millimetrique. The Max Planck Institute for Radio Astronomy in Germany provides additional support by using its supercomputer to combine EHT data from multiple observatories.
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