In the vast space, China's "eyes" know heroes.
The latest discovery, there is a "crown" that can escape the black hole!
For the celestial black hole with extremely strong gravitational force in the universe, people often use "light can not escape" to describe it as terrible enough to swallow everything.
However, the latest research by a team of Chinese scientists through the observational data of China’s first space X-ray astronomical satellite "Hui Eye" (HXMT) found that a plasma stream commonly known as "corona" can escape the black hole, which will give people a strong gravitational attraction to the black hole. New understanding of the field.
The "Wise Eye" satellite detected the dynamic evolution of the corona for the first time.
Photo courtesy of the research team
Discover the "corona" that escaped the black hole
The reporter learned from the Institute of High Energy Physics of the Chinese Academy of Sciences (Institute of High Energy Physics, Chinese Academy of Sciences) on February 15 that the internationally renowned academic journal "Nature Communications" published online the latest scientific research results of China's "Wisdom Eye" satellites on the same day-the team of scientists analyzed the "Wisdom Eye" satellite observations According to the data, the corona that escaped the strong gravitational field of the black hole was discovered in the black hole X-ray binary star "MAXI J1820+070", and the velocity evolution of the corona was observed for the first time in the black hole binary star.
The study shows that the corona tends to shrink toward the black hole, and it also moves outward at a relativistic speed, and the smaller the scale of the corona, the greater the speed.
At the same time, this result also provides an important basis for studying the motion of the coronal in the process of black hole accretion.
The latest result of the paper is titled "The "Wisdom Eye" satellite discovered the outward moving corona in the black hole X-ray binary star MAXI J1820+070", jointly by researchers from Wuhan University, Institute of High Energy Energy, Chinese Academy of Sciences, National Astronomical Observatory of Chinese Academy of Sciences, Nanjing University, Tsinghua University and other researchers carry out.
Dr. You Bei from the Center for Astrophysics of Wuhan University is the first author. Professor Wang Wei of Wuhan University and researcher Zhang Shuangnan from the Institute of High Energy Research of the Chinese Academy of Sciences are the co-corresponding authors.
Black hole X-ray binary star research history
According to the Institute of High Energy, Chinese Academy of Sciences, as early as the 1960s, astronomers detected X-ray radiation sources in the Milky Way.
Among these X-ray sources, Cygnus X-1 (Cygnus X-1) is the first binary star system thought to have a black hole.
Since then, with the development of astronomy, more and more black hole X-ray binary star systems have been discovered in the Milky Way.
It is generally believed that in black hole X-ray binary stars, the companion star material is captured by the black hole's gravity, and rotates and gradually moves toward the black hole, forming an accretion disk structure, and a high-temperature corona is formed near the inner region of the accretion disk.
However, how the corona moves near the black hole has always been an unsolved mystery in the study of compact celestial bodies.
The evolution of the intensity of the thermal corona on the accretion disk.
Photo courtesy of the research team
In March 2018, the black hole X-ray binary star MAXI J1820+070, which is about 11,300 light-years away from the earth, broke out, and it was one of the brightest X-ray sources in the sky for a long time. The explosion of this celestial body is observed frequently.
In 2020, a research team led by the Institute of High Energy of the Chinese Academy of Sciences analyzed the time-varying data of the "Wisdom Eye" satellite and found the highest energy low-frequency quasi-periodic oscillation (QPO) signal so far in MAXI J1820+070, providing a signal that is emitted from near the black hole horizon. Observational evidence of relativistic jets (plasma flows moving outward at high speed).
Recently, a research team led by the Center for Astrophysics of Wuhan University has analyzed the energy spectrum data of the "Wisdom Eye" satellite and found that when the X-ray radiation intensity gradually decreases, that is, when the corona gradually weakens, the degree of exposure to the accretion disk (that is, from the corona) The ratio of the outgoing photons to the flow rate of the accretion disk and infinity) is also weakening.
The research team pointed out that the intensity of the X-ray photons emitted from the corona on the accretion disk depends on the speed of the corona and the gravitational field of the black hole.
Data map: The artistic imagination of the low-frequency QPO originating from the high-speed jet precessing around the black hole.
Photo courtesy of the "Wise Eye" satellite team of the Institute of High Energy, Chinese Academy of Sciences
The latest "Mian Wang" research confirmed
The crown that can escape the gravitational pull of a black hole is certainly called the "king of crown", and research confirms that its "crowning" has attracted much attention.
The research team pointed out that it is not clear how the corona moves during the accretion of a black hole. Previous studies have focused more on theory, with relatively little observational evidence.
Theoretically, when the corona moves outwards at a relativistic speed, the relativistic bundling effect will weaken the corona's radiation to the accretion disk.
The team’s X-ray time-varying analysis of MAXI J1820+070 in the same period showed that when the X-ray radiation intensity gradually decreases, the geometric scale of the corona tends to shrink (that is, the scale is decreasing); the closer to the black hole, the gravitational bending effect The stronger, the larger the opening angle of the accretion disk relative to the corona, and the X-ray photons radiated by the corona should irradiate the accretion disk in a larger proportion, enhancing the corona’s radiation to the accretion disk.
Data map: Artistic imagination of the quasi-periodic modulated signal generated by the jet stream closest to the black hole discovered by the "Huiyan" satellite.
Photo courtesy of the "Wise Eye" satellite team of the Institute of High Energy, Chinese Academy of Sciences
This is contrary to the analysis results of the research team on the observational data of "Wisdom Eye". Why?
The research team believes that the most reasonable explanation for this phenomenon is that while the crown is shrinking, the plasma flow in the crown is moving outward at a relativistic speed.
This provides independent observational evidence and physical explanations for the relativistic jets that are close to the black hole that the "eyes" team has discovered.
Further research found that the smaller the coronal size, the greater the velocity, so the relativistic bundling effect of the coronal matter motion suppresses the gravitational bending effect of the black hole.
The research team stated that the important results of the discovery and confirmation of the "Mianwang" are the first systematic depiction of the evolution of the velocity of the plasma stream escaping the gravitational field of the black hole during the explosion of the black hole X-ray binary star, which is useful for understanding the process of black hole accretion and The effect of relativity is of great significance.
Data map: The "Wisdom Eye" satellite detected low-frequency QPO with energy above 200keV for the first time.
Photo courtesy of the "Wise Eye" satellite team of the Institute of High Energy, Chinese Academy of Sciences
The "Huiyan" satellite shows its comprehensive advantages. The latest research result of the "Crown" is that the "Huiyan" satellite uses its time-varying data to discover a plasma flow and its relativistic velocity moving outwards near the black hole horizon of MAXI J1820+070. During the precession process, at the same time, using the energy spectrum data of the "Smart Eye" satellite, we also discovered the evolution of the plasma flow and its velocity moving outwards at a relativistic velocity.
According to the research team, these two mutually corroborating research results demonstrate the comprehensive advantages of the "Wise Eye" satellite for wide-energy range time-varying and energy spectrum research.
It is understood that the Hard X-ray Modulation Telescope (HXMT) satellite is China’s first space astronomy satellite (also known as space astronomy telescope, space astronomy observatory), which can achieve wide-band, The large field of view X-ray survey can also study the short-time scale light variation and wide-band energy spectrum of high-energy celestial bodies such as black holes and neutron stars. It is also a gamma-ray burst all-sky monitor with high sensitivity.
Data map: "Wisdom Eye" satellite's artistic imagination map in space.
Photo courtesy of the "Wise Eye" satellite team of the Institute of High Energy, Chinese Academy of Sciences
As China's first space X-ray telescope, the "Wisdom Eye" satellite officially entered the engineering development stage in 2011, and was successfully launched in mid-June 2017 to carry out scientific observations.
It carries three high-, medium-, and low-energy X-ray telescopes. The main scientific objectives include: searching for new temporary sources on the silver disk, monitoring known sources of variation; and observing X-ray binary stars to study the effects of strong gravitational or magnetic fields. Motion and radiation mechanism; monitor and study gamma-ray bursts and gravitational wave electromagnetic counterparts.
The "Wisdom Eye" satellite project was proposed by the Institute of High Energy of the Chinese Academy of Sciences and took the lead in charge of satellite payloads, ground application systems and scientific research. Its successful launch and operation have given China an important place in the highly competitive high-energy astrophysics observation field.
Reporter: Sun Zifa