ROSCOSMOS & DLR - Spectrum-RG (Spektr-RG) patch.
Oct. 21, 2021
The LOFAR radio interferometer and the eROSITA telescope, installed at the Russian orbiting astrophysical observatory Spektr-RG, are studying impressive traces of supermassive black hole activity hundreds of millions of years ago in a nearby group of galaxies. By combining radio and X-ray images, astrophysicists have investigated a group of galaxies that contain an unusually rich array of radio-bright filaments immersed in an atmosphere of hot X-ray emitting gas. The results of the study are published in the journal Nature Astronomy.
These filaments were originally formed as a result of the activity of a supermassive black hole several hundred million years ago - around the time when dinosaurs appeared on Earth. Despite their venerable age, the filaments still have clear boundaries and form a strikingly complex web of filaments and geometric shapes, reminiscent of the structures that form when hot clouds of smoke rise in the atmosphere. The absence of complete mixing between X-ray and radio-emitting plasmas is especially interesting for the development of physical models of the influence of supermassive black holes on the environment.
Massive halos in our Universe, such as giant elliptical galaxies, galaxy groups and clusters are mostly composed of dark matter that forms their deep gravitational pits. However, a small part of their mass is accounted for by ordinary matter, that is, baryons, which form a hot (10 or 100 million degrees) gaseous atmosphere that fills the potential well of the halo. This gas emits in the X-ray range and is studied using modern space observatories such as, for example, Chandra (NASA), XMM-Newton (ESA) and Spektr-RG (Roscosmos State Corporation).
In the central part of each halo, the gas density is high, and it can cool and condense, providing material for the formation of new stars. However, for some reason this does not happen, and old stars dominate in the center of the halo. This mystery led to the development of a theory about the effect of supermassive black holes in cluster centers on the environment - the so-called feedback mechanism. According to this theory, as the gas cools, the supermassive black hole increases the accretion rate and begins to release a huge amount of mechanical energy in the form of plasma jets. This energy heats up the gas, preventing it from further cooling.
There are many analytical and numerical models that support this idea. But from first principles it is difficult to say unambiguously which specific physical processes are responsible for heating a relatively cold gas in a halo. These can be waves, turbulence, cosmic rays, viscosity, etc. To answer these questions, it is necessary to study nearby clusters and groups of galaxies, and preferably in different spectral ranges, since gas of different temperatures emits photons of different energies.
NEST200047 is one of the closest group of galaxies, about 75 megaparsecs from us (for comparison, the distance from the solar system to the center of our Galaxy is only 8 kiloparsecs). It is one of tens of thousands of similar objects found in galaxy catalogs. It was observed by radio telescopes of the ground-based radio interferometer LOFAR (short for Low Frequency Array, created by the Dutch Institute of Radio Astronomy ASTRON) and the eROSITA space telescope in radio and X-ray surveys. The characteristic wavelengths of these telescopes differ by about 5 billion times, and the data from the two observatories complement each other perfectly.
The X-ray data were obtained during two surveys of the entire sky by the Russian observatory "Spektr-RG". The effective exposure was 645 seconds. These observations confirm that the NEST200047 group has a hot gas atmosphere emitting X-rays. At its center is a giant elliptical galaxy, the core of which is a bright radio source. These are typical components for a group of galaxies in which the central black hole plays an important role.
The NEST200047 turned out to be very special. Radio emission comes not only from the center, but also from a rich and complex system of fibers covering an area of more than 200 kiloparsecs. It shows structures that resemble vortex rings. They are similar to those previously found in the famous galaxy M87, but ten times larger. Radio and X-ray images show that the plasma ejected by the supermassive black hole was deformed by complex motions over a hundred million years, but during this time it has not completely mixed with the surrounding thermal plasma, most likely due to the presence of a dynamically important magnetic fields.
Spectrum-RG (Spektr-RG)
Overall, NEST200047 provides a unique example of an object that can trace the history of a supermassive black hole's activity over hundreds of millions of years. Rising bubbles of relativistic plasma work like a giant spoon, "stirring" the thermal X-ray plasma, preventing it from cooling.
The study is the result of a collaborative effort by an international group of astrophysicists. It included employees of the Institute of Space Research of the Russian Academy of Sciences E. Churazov, I. Khabibullin, N. Lyskova, R. Burenin and R. Sunyaev and Kazan Federal University I. Bikmaev, as well as the University of Bologna, INAF, Turin Observatory (Italy), Leiden Observatory, ASTRON (Netherlands), Hamburg Observatory, Institute of Astrophysics Society. Max Planck (Germany), University of Herdfordshire (UK), IASF, DIAS, SRON, WPI, Paris Observatory (France), Rhodes University (South Africa).
Black Holes, Neutron Stars, White Dwarfs, Beyond Space and Time
The Spektr-RG spacecraft, developed at the S.А. Lavochkin (part of the Roscosmos State Corporation), was launched on July 13, 2019 from the Baikonur cosmodrome. It was created with the participation of Germany within the framework of the Federal Space Program of Russia by order of the Russian Academy of Sciences. The observatory is equipped with two unique X-ray mirror telescopes: ART-XC (IKI RAS, Russia) and eROSITA (MPE, Germany), operating on the principle of oblique incidence X-ray optics. The telescopes are installed on the Navigator space platform (NPO Lavochkina, Russia), adapted to the project's objectives. The main goal of the mission is to map the entire sky in the soft (0.3–8 keV) and hard (4–20 keV) ranges of the X-ray spectrum with unprecedented sensitivity. The observatory must operate in space for at least 6.5 years.
Scientific director of the orbital X-ray observatory "Spektr-RG" Academician Rashid Sunyaev Scientific director of the ART-XC telescope named after M.N. Pavlinsky (Russia): Professor of the Russian Academy of Sciences Alexander Lutovinov Supervisor of the eROSITA telescope (Germany): Dr. Andrea Merloni.
Source: IKI RAN.
Related links:
ROSCOSMOS Press Release: https://www.roscosmos.ru/33030/
IKI RAN: https://www.roscosmos.ru/tag/iki-ran/
Spektr-RG: https://www.roscosmos.ru/tag/spektr-rg/
Images, Video, Text, Credits: ROSCOSMOS/IKI RAN/Evren Cinarli/Orbiter.ch Aerospace/Roland Berga.
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