by 
Astronomers have taken unprecedented images of a jet of plasma emanating from a supermassive black hole in blazar 3C 279, revealing complex patterns that challenge existing theories. This international effort, using advanced radio telescope networks, discovered helical filaments near the source of the jet, indicating the potential role of magnetic fields in the formation of such jets. (Artist’s concept.)
A telescope larger than Earth has found a plasma string in the Universe.
Using a network of radio telescopes on Earth and in space, astronomers have captured the most detailed view ever seen of a jet. The jet, which comes from the heart of a distant blazar called 3C 279, travels at nearly the speed of light and shows complex, distorted patterns near its source. These patterns challenge the standard theory that has been used for 40 years to explain how these jets form and change over time.
A major contribution to the observations was made possible by the Max Planck Institute for Radio Astronomy in Bonn, Germany, where data from all participating telescopes were combined to create a virtual telescope with an effective diameter of around 100,000 kilometers.
Their findings were recently published in Nature Astronomy.
Figure 1: Entangled filaments in blazar 3C 279. High-resolution image of the relativistic jet in this source as observed by the RadioAstron program. The image reveals a complex structure within the jet with several parsec-scale filaments forming a helix. The set includes data from radio telescopes around the world and in Earth orbit, among them the 100 m Effelsberg Radio Telescope. The data was post-processed at the correlation center at the Max Planck Institute for Radio Astronomy. Credit: NASA/DOE/Fermi LAT Collaboration; VLBA/Jorstad et al.; RadioAstron/Fuentes and others
Insights into Blazares
Blazars are the brightest and most powerful sources of electromagnetic radiation in the cosmos. They are a subclass of active galactic nuclei comprising galaxies with a central supermassive black hole that accretes matter from a surrounding disk. About 10% of active galactic nuclei, classified as quasars, produce relativistic plasma jets. Bazaars belong to a small fraction of quasars in which we can see these jets pointing almost directly at the observer.
Recently, a team of researchers, including scientists from the Max Planck Institute for Radio Astronomy (MPIfR) in Bonn, Germany, imaged the innermost region of the jet in blazar 3C 279 with unprecedented angular resolution and detected remarkably regular helical filaments that can require a review of the theoretical models used so far to explain the processes by which jets are produced in active galaxies.
“Thanks to RadioAstron, the space mission for which the orbiting radio telescope reached distances as far as the Moon, and a network of twenty-three radio telescopes distributed across Earth, we have obtained the highest resolution image of the interior of a blazar up to date, allowing us to observe for the first time the internal structure of the jet in such detail”, says Antonio Fuentes, researcher at the Institute of Astrophysics of Andalusia (IAA-CSIC) in Granada, Spain, who is leading the work.
Implications and theoretical challenges
The new window on the universe opened by the RadioAstron mission has revealed new details in the plasma jet of 3C 279, a blazar with a supermassive black hole at its core. The jet has at least two twisted filaments of plasma that extend more than 570 light-years from the center.
“This is the first time we have seen such filaments so close to the origin of the jet, and they tell us more about how the black hole shapes the plasma. The inner jet was also observed by two other telescopes, the GMVA and the EHT, at much shorter wavelengths (3.5 mm and 1.3 mm), but they were unable to detect the filamentary forms because they were too faint. and too large for this resolution. ” says Eduardo Ros, member of the research team and European scheduler at GMVA. “This shows how different telescopes can reveal different features of the same object,” he adds.
Figure 2: RadioAstron VLBI observation provides a virtual telescope up to eight times the diameter of Earth (maximum baseline 350,000 km). Credit: Roscosmos
The plasma jets coming from blazars are not really straight and uniform. They show twists and turns that show how the plasma is affected by the forces around the black hole. Astronomers studying these twists in 3C279, called helical filaments, discovered that they were caused by instabilities developing in the jet’s plasma. In the process, they also realized that the old theory they used to explain how jets changed over time no longer worked. Therefore, new theoretical models are needed that can explain how such helical filaments form and evolve so close to the origin of the jet. This is a great challenge, but also a great opportunity to learn more about these incredible cosmic phenomena.
“A particularly intriguing aspect arising from our results is that they suggest the presence of a helical magnetic field confining the jet,” says Guang-Yao Zhao, currently affiliated with MPIfR and a member of the team of scientists. “So it may be the magnetic field, which rotates clockwise around the jet in 3C 279, that directs and guides the jet plasma moving at a speed of 0.997 times the speed of light.”
“Similar helical filaments have been observed in extragalactic jets before, but on much larger scales, where they are thought to result from different parts of the flow moving at different speeds and cutting against each other,” adds Andrei Lobanov, another MPIfR scientist at team of researchers. . “With this study, we are entering completely new terrain, in which these filaments may actually be linked to the most complex processes in the vicinity of the black hole that produces the jet.”
The study of the internal jet in 3C279, now featured in the latest issue of Nature Astronomy, extends the ongoing effort to better understand the role of magnetic fields in the early formation of relativistic outflows from active galactic nuclei. It highlights the numerous remaining challenges to current theoretical modeling of these processes and demonstrates the need for further improvements in radio astronomical instruments and techniques that offer the unique opportunity to image distant cosmic objects with record angular resolution.
Technological Advances and Collaboration
Using a special technique called Very Long Baseline Interferometry (VLBI), a virtual telescope with an effective diameter equal to the maximum separation between the antennas involved in an observation is created by combining and correlating data from different radio observatories. RadioAstron project scientist Yuri Kovalev, now at MPIfR, emphasizes the importance of healthy international collaboration to achieve such results: “Observatories from twelve countries were synchronized with the space antenna using hydrogen clocks, forming a distance-sized virtual telescope. to the Moon.”
Anton Zensus, director of MPIfR and one of the driving forces behind the RadioAstron mission over the past two decades, says: “The experiments with RADIOASTRON that led to images like these of quasar 3C279 are exceptional achievements made possible through international scientific collaboration of observatories. and scientists in many countries. The mission took decades of joint planning before the satellite was launched. Taking the real images became possible by connecting large telescopes on the ground, such as the Effelsberg, and through careful analysis of the data at our VLBI correlation center in Bonn.”
Reference: “Filamentary structures as the origin of blazar jet radio variability” by Antonio Fuentes, José L. Gómez, José M. Martí, Manel Perucho, Guang-Yao Zhao, Rocco Lico, Andrei P. Lobanov, Gabriele Bruni, Yuri Y .Kovalev, Andrew Chael, Kazunori Akiyama, Katherine L. Bouman, He Sun, Ilje Cho, Efthalia Traianou, Teresa Toscano, Rohan Dahale, Marianna Foschi, Leonid I. Gurvits, Svetlana Jorstad, Jae-Young Kim, Alan P. Marscher, Yosuke Mizuno, Eduardo Ros and Tuomas Savolainen, October 26, 2023, Nature Astronomy.
DOI: 10.1038/s41550-023-02105-7
Other information
The Earth-to-Space Interferometer RadioAstron mission, active from July 2011 to May 2019, consisted of a 10-meter orbiting radio telescope (Spektr-R) and a collection of about two dozen of the world’s largest ground-based radio telescopes, including the 100 m Effelsberg radio telescope. When signals from individual telescopes were combined using radio wave interference, this array of telescopes provided maximum angular resolution equivalent to a radio telescope 350,000 km in diameter – almost the distance between the Earth and the Moon. This made RadioAstron the instrument with the highest angular resolution in the history of astronomy. The RadioAstron project was led by the Astro Space Center of the Lebedev Physical Institute of the Russian Academy of Sciences and the Lavochkin Scientific and Production Association under a contract with the State Space Corporation ROSCOSMOS, in collaboration with partner organizations in Russia and other countries. Astronomical data from this mission is being analyzed by individual scientists around the world, producing results like those presented here.
The following contributors to the presented work are affiliated with MPIfR, in order of appearance in the list of authors: Guang-Yao Zhao, Andrei P. Lobanov, Yuri Y. Kovalev, Efthalia (Thalia) Traianou, Jae-Young Kim, Eduardo Ros, and Tuomas Savolainen. Collaborators Rocco Lico and Gabriele Bruni were also affiliated with MPIfR during the RadioAstron mission.
Yuri Y. Kovalev recognizes the Friedrich Wilhelm Bessel Research Award from the Alexander von Humboldt Foundation.
