Just over a month ago, an international groupAstrophysicists of the Event Horizon Telescope project (EHT), in which scientists combined several radio telescopes in different parts of the world to create a huge virtual radio interferometer the size of Earth, published the first ever black hole photograph in history. Now another group of scientists, consisting of astronomers from the University of Nijmegen in the Netherlands and specialists from the European Space Agency (ESA), has set a goal to obtain even clearer images of the black hole that will allow Einstein’s general theory of relativity to be tested. The researchers proposed a concept that, in their opinion, would solve this problem. Their idea is accepted for publication in the journal Astronomy & Astrophysics.
The concept of European scientists, calledEvent Horizon Imager (EHI), involves placing two or three satellites in a circular orbit around the Earth. The researchers conducted computer simulations that show how much more detailed pictures of the black hole Sagittarius A can be taken, which is located in the center of our galaxy and has become the target of the EHT ground virtual telescope.
Five times sharper images
"There are many advantages to usingsatellites instead of stationary radio telescopes on Earth, such as the same Event Horizon Telescope (EHT), ”says Frick Roelofs PhD candidate at the University of Nijmegen and lead author of the new article.
"In space, you can make observations onhigher radio frequencies, because on Earth they are filtered by the atmosphere of the planet. In addition, the distance between the telescopes in space can be even greater. This will allow us to take a big step forward. We will be able to get images that will be five times higher in quality than the quality of images that can be obtained with the help of EHT, ”the scientist adds.
The ability to get clearer images of a black hole will allow us to gather more information, which is useful for more accurate testing of Einstein’s general theory of relativity.
"The fact that the satellites will orbit around the Earth will also provide us with additional benefits," says Heino Falke, a professor of radio astronomy.
"Thanks to this, you can get almostperfect images and consider the real details of the black hole. If in reality there are some inconsistencies of Einstein's theory, we will be able to see them. ”
According to the researchers, EHI will be able to getimages of five additional black holes that are smaller in size than those explored by the EHT virtual ground-based telescope. Speech in the latter case is about the central black hole of our galaxy, Sagittarius A, as well as the central black hole M87 of the massive elliptical galaxy Messier 87, located in the constellation Virgo.
In space, the EHI resolution will be five times higherthan the terrestrial virtual telescope EHT. The image of black holes can be obtained at an even higher level of detail. The image in the upper left corner shows a snapshot of the Black Hole Sagittarius, how EHT saw it at 230 GHz. Its computer model is displayed at the top right. In the lower left corner, the Strelets A model is shown when observed at a frequency of 690 GHz. The bottom right shows the image of a computer model, how it can see the EHI space virtual telescope
Researchers modeled images thatcould be obtained by using different visualization technologies. To do this, they turned to the previously developed models of plasma behavior and radiation around a black hole.
“From a scientific point of view, the models look very promising, but several technological difficulties have to be overcome in order to achieve such a result in reality,” Roelofs comments.
To assess the technical feasibility ofThe project to create the EHI space virtual telescope, astronomers have joined forces with specialists from the European Space Research and Technology Center (ESTEC), created by ESA.
"This concept requires a very accurate calculationposition and velocity of space satellites. But we believe that the project is truly feasible, ”comments Vladimir Kudryashov from the radio laboratory at the University of Nijmegen, which also collaborates with ESTEC.
Experts note that it is also important to consider how scientists will be able to receive data collected by satellites.
"Data from the EHT ground virtual telescopeThey were recorded on hard drives, and then transported to the decryption center with the help of an airplane. Such an approach, of course, is not applicable to space, ”says Kudryashov.
Scientists suggest to transfer datause lasers. In this case, part of the collected data will be processed directly on board the satellites themselves, and then transferred to Earth for further analysis.
“Similar technologies in space are already being used,” adds Kudryashov.
At its core, the idea of ESA andThe University of Nijmegen assumes the independent operation of the EHI virtual space telescope. However, scientists are considering the possibility of using a kind of hybrid system in which they will combine into a single network the power of the virtual ground telescope EHT and the orbital EHI.
"The use of such a hybrid system canto enable us to create a dynamic image of a black hole, as well as to consider even weaker sources of radio emission in the adjacent area of the object, ”concludes Falke.
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