Astronomers have proposed the idea of how to get a more clear picture of a black hole
Just over a month ago, an international team of astrophysicists Project Event Horizon Telescope (EHT), in which researchers combine several radio telescopes in different parts of the globe to create a huge virtual radiointerferometer the size of Earth, published the first-ever picture of a black hole. Now another group of scientists, consisting of Dutch astronomers at the University of Nijmegen and the European Space Agency experts (ESA), has set a goal - to get an even clearer image of a black hole that will verify Einstein's general theory of relativity. Researchers have proposed a concept that, in their opinion, will allow to solve this problem. Their idea is accepted for publication in the journal Astronomy & Astrophysics.
The concept of European scholars, called Event Horizon Imager (EHI), involves placing a circular orbit around the Earth two or three satellites. The researchers conducted computer simulations that show how much more you can get detailed images of the black hole Sagittarius A, which is at the center of our galaxy, and became the target of a virtual ground telescope EHT.
In the five times sharper images
"There are many advantages of using satellites instead of stationary radio telescopes on Earth, such as the same Event Horizon Telescope (EHT)", - says Freek Roelofs PhD candidate at the University of Nijmegen and the lead author of a new article.
"In space, you can make observations at higher radio frequencies, as on Earth, they are filtered by the atmosphere of the planet. In addition, the distance between the telescopes in space may be more. This will allow us to take a big step forward. We will be able to obtain images that the quality will be five times higher than the quality of images that can be obtained with EHT ", - adds the scientist.
The ability to get a clearer picture of the black hole will allow to gather more information, which will be useful for more accurate testing of Einstein's general theory of relativity.
"The fact that the satellites will move in an orbit around the Earth and will provide us with additional benefits," - says Professor Heino astronomy Falke.
"With this you can get near-perfect images and see the real details of the black hole. If in reality there are some inconsistencies of Einstein's theory, we can see them. "
According to the researchers, EHI can receive five additional images of black holes, which are smaller than those that explores the virtual ground EHT telescope. In the latter case it is the central black hole of our galaxy, Sagittarius A, as well as the central black hole M87 a massive elliptical galaxy Messier 87, located in the constellation Virgo.
In the space EHI resolution is five times higher than that of terrestrial virtual telescope EHT. Image of black holes will be available at an even higher level of detail. The image in the upper left corner of the picture shows the black hole Sagittarius A, how it saw EHT at a frequency of 230 GHz. Displayed at the top right of its computer model. In the lower left corner shows a model of Sagittarius A at a frequency of observations at 690 GHz. Bottom right image shows a computer model of how it can see the virtual space telescope EHI
The technological challenge of
The researchers modeled the images that would be obtained by using different imaging techniques. To do this, they turned to previously developed models of behavior of plasma and radiation around the black hole.
"From a scientific point of view, the model look very promising, but will have to overcome several technological difficulties, to achieve such a result in reality", - says Roelofs.
In order to evaluate the technical possibilities of the project to create a virtual space telescope EHI astronomers teamed up with the experts of the European Space Research and Technology (ESTEC), created by ESA.
"This concept requires a very accurate calculation of the position and velocity of satellites. But we believe that the project is really feasible, "- commented Vladimir Kudryashov from the Radio Laboratory at the University of Nijmegen, which is also working with ESTEC.
Experts note that it is also important to consider how scientists can receive the data collected by satellites.
"The data from ground-based virtual telescope EHT recorded on hard drives, and then use the aircraft were transported to the center of decryption. This approach, of course, is not applicable to outer space ", - said Kudryashov.
Scientists propose to transfer data using lasers. In this part of the collected data is processed directly on board the satellites themselves, then transmitted to Earth for further analysis.
"These technologies are already being used in space", - adds Kudryashov.
The hybrid system
At its core, the idea of the ESA and the University of Nijmegen experts assumes the independent work of the Virtual Space Telescope EHI. However, scientists are considering the possibility of use and kind of a hybrid system which will be combined into a single virtual network capacity terrestrial telescope and EHT orbital EHI.
"The use of such hybrid systems can provide us an opportunity to create a dynamic image of a black hole, as well as to consider even more weak radio sources in the surrounding area of the object" - sums up Falke.
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