A record-breaking astronomical advance. Combining up to 15 terrestrial antennas distributed throughout the planet and the RadioAstron space mission of the Russian Space Agency (Roscosmos), a team of astronomers led by researchers from the CSIC at the Institute of Astrophysics of Andalusia (Spain) has achieved the image with the best resolution never obtained in astronomy.
The terrestrial radio telescopes, together with the satellite, have formed a telescope equivalent to eight times the diameter of the Earth, which has made it possible to obtain an image with unprecedented detail and quality. The point chosen for the observation was the environment of the black hole in the core of the active galaxy (the most energetic objects in the universe) BL Lacertae, located 900 million light years from us.
The technique used has been very long base interferometry (VLBI) that allows multiple geographically separated radio telescopes to work at the same time: the result is a single telescope with a diameter equivalent to the maximum distance that separates them. The images are therefore more than 1,000 times better than those that can be obtained by the well-known NASA / ESA Hubble space telescope.
“By combining terrestrial antennas and the RadioAstron orbiting antenna for the first time, we have achieved the resolution that an antenna with a size equivalent to eight times the Earth’s diameter would have, about twenty microseconds of arc”, explains José Luis Gómez, leader of the study.
From Earth, the 20 microseconds of arc would correspond to the size of a two-euro coin on the surface of the Moon. Thus, experts have been able to identify with a high level of precision the central areas of this object, which is fed by a black hole about 200 million times the mass of the Sun.
Furthermore, this excellent resolution has also made it possible to discover that the energy concentration of the nucleus is well above what has been observed so far in active galaxies: “in BL Lacertae we are observing the hottest areas of the Cosmos, a ‘furnace’ thousands of millions of times hotter than the Sun ”, explains Andrei Lobanov, co-author of the study. This radiation emitted per unit area is too high and constant, which is why scientists are faced with a new situation that will have to be deepened.
The work has been published in The Astrophysical Journal.
Image credit: Wolfgang Steffen.
