0319 GMT March 20, 2019
"This result is very challenging to explain with our current understanding of how relativistic jets of quasars radiate," said lead author Yuri Kovalev of the Moscow's Lebedev Physical Institute in a statement.
Observations of quasar 3C 273 were done with the Russian Skeptr-R satellite working in concert with three ground observatories as part of the larger RadioAstron mission. Quasars are supermassive black holes that emit intense jets of radiation.
Previously, it was believed there was a limit to the temperature because the electrons inside the jet would produce X-rays and gamma rays, interact with each other and cool down.
Astronomers hailed the finding as a triumph for interferometry, which occurs when multiple telescopes are linked together to get fine resolution of a distant object. The four observatories working together can get better resolution than the Hubble Space Telescope (although Hubble does not observe in X-rays or gamma rays).
The team also had a secondary find, which was that 3C 273 had previously unknown visible distortions to its substructure as seen from Earth, caused by peering through the interstellar medium in our own Milky Way. The distortion was only spotted because of the resolution of RadioAstron, researchers said in a statement. The results were published in the Astrophysical Journal.