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Posted on May 6, 2019
In the space, you can observe a supermassive black hole at higher radio frequencies, because the frequencies of the Earth are filtered by the atmosphere. The distances between the telescopes in the space are also larger. "It allows us to take a big step forward. We would be able to take images with a resolution more than five times higher than is possible with the EHT, "said Freek Roelofs, of Radboud University, about the benefits of using space satellites rather than permanent radio telescopes on Earth, as with Event Horizon. Telescope (EHT).
The idea is that satellites will initially work independently of EHT telescopes. A hybrid system is also envisaged, the orbiting telescopes being combined with those of the Earth. The use of a hybrid could offer the ability to create animated images of a black hole, and you may be able to observe even more weaker sources, she says. Heino Falcke, professor of radioastronomy at Radboud University.
"The Last Photon Orbit" – Milky Way's supermassive black hole for the EHT platform
Astronomers have just managed to take the first image of a black hole and the next challenge is to know how to take images even sharper, so as to test the theory of general relativity Einstein. Astronomers from Radboud University, as well as the European Space Agency (ESA) and others, are proposing a concept to achieve this goal by launching radio telescopes in the space.
The idea is to place two or three satellites in circular orbit around the Earth to observe black holes. The concept is called Event Horizon Imager (EHI). In their new study, scientists present simulations of what Sagittarius A * black hole images could look like if they were taken by satellites like these.
More than five times stronger
Sharper images of a black hole will provide better information that could be used to further test Einstein's theory of general relativity. "The fact that satellites move around the Earth offers tremendous benefits," says Professor Heino Falcke, a radio astronomy specialist. "With them you can take almost perfect pictures to see the real details of black holes. If small deviations from Einstein's theory occur, we should be able to see them. "
"The gates of hell, the end of space-time" – Scientists from around the world speak out on the photo of the EHT black hole
The EHI will also be able to image about five additional smaller black holes than those on which the EHT is currently focusing. The latter are Sagittarius A * in the center of our Milky Way and the M87 * in the center of Messier 87, a gigantic galaxy of the Virgin group.
In the space, the EHI has a resolution more than five times higher than that of the EHT on Earth and the images can be reconstructed with greater fidelity. Top left: Sagittarius A * model with an observation frequency of 230 GHz. Top left: Simulation of an image of this model with the EHT. Bottom left: Sagittarius model A * at a frequency of 690 GHz. Bottom right: Simulation of an image of this model with the IEH. (F. Roelofs and M. Moscibrodzka)
Technological challenges
The researchers simulated what they could see with different versions of the technology under different circumstances. To do this, they used models of plasma behavior around the black hole and the resulting radiation. "The simulations look promising from a scientific point of view, but it's hard to overcome the technical difficulties," says Roelofs.
Astronomers collaborated with scientists from ESA / ESTEC to study the technical feasibility of the project. "The concept requires that you be able to know precisely the position and speed of satellites," said Volodymyr Kudriashov, a researcher at Radboud Radio Lab, also at ESA / ESTEC. "But we really believe that the project is achievable."
"Paradoxical, intriguing, scary" – The black hole bigger than our solar system
It is also important to consider how satellites exchange data. "With the EHT, hard drives containing data are transported to the air handling center. This is of course impossible in space. In this concept, the satellites exchange data by laser link, the data being partially processed on board before being returned to Earth for further analysis. "There are already laser links in the space," notes Kudriashov.
The GRAVITY instrument on the very large telescope of the European Southern Observatory has recently discovered new information on the supermassive central black hole of the Milky Way, shown at the top of the page. (ESO / Consortium Gravity / L. Calçada)
The Daily Galaxy via the Radboud University of Nijmegen
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