At the center of many galaxies,supermassive black hole” exists, and in the process of inhaling large amounts of gas, it radiates a huge amount of energy. Analysis of the flow of matter toward a black hole on a scale smaller than a few tens of light years has not been well understood.
A research team led by Takuma Izumi of the National Astronomical Observatory of Japan is developing a large-scale radio interferometer calledALMA (Atacama Large Millimeter/Submillimeter Interferometer) (Atacama Desert, Chile)Compass constellation galaxyWe observed the center of the black hole and analyzed in detail the flow of gas flowing into the black hole. the result,Succeeded in analyzing the material state and momentum of gas on an extremely small scale of about 1 light yearDid. This is the highest resolution analysis of this type of research.
[▲Figure1:AnimaginarydrawingoftheareaaroundablackholethatreflectstheresultsofthisresearchPlasmagasflowsverticallyawayfromtheblackholewhilemolecularandatomicgasesflowdiagonallyIthasalsobeenrevealedthatthisgasflowmoveslikeafountainreturningtotheaccretiondisk(Credit:ALMA(ESO/NAOJ/NRAO)TIzumietal)
■Details of the situation around the black hole are unknown.
Almost all galaxies have a “supermassive black hole‘ is known to exist. A black hole’s powerful gravity pulls in a large amount of matter, but because a black hole’s size is small compared to its gravitational strength, the attracted matter concentrates and creates a traffic jam. What is formed at this time is the “accretion disk“is.
The materials in the accretion disk rub against each other, reaching temperatures of several million degrees Celsius, and emitting a huge amount of energy, mainly X-rays. Sometimes it is more than the sum of the radiation from all the stars in the galaxy, and galaxies with such active centers are known as “active galaxy” is called.
Because the energy radiation becomes more intense as you move toward the center, it is thought that some of the matter in the accretion disk does not fall into the black hole, but flies out on the radiation. The flow of matter to such black holes has been well analyzed both theoretically and observationally, from the scale of 100,000 light-years, which includes the entire galaxy, to the scale of several hundred light-years, which is the scale of the center of the galaxy.
However, the density of matter extremely close to a black hole is high, making direct observation difficult. In addition, near a black hole, the speed and temperature of matter change drastically, and the movement also changes depending on whether the state of the material is molecules, atoms, or plasma. Analysis that takes these into account requires a huge amount of calculations, and it is difficult to consider it theoretically. For this reason, there are many mysteries about the movement of matter in units smaller than a few tens of light years, which are extremely close to a black hole, including the basic question of what proportion of matter is sucked into the black hole or escapes. Even I didn’t really understand.
■ Observe the detailed flow of gas with “ALMA”
[▲Figure 2: False color image of the center of the Compass galaxy observed with ALMA. The molecular gases carbon monoxide (red) and hydrogen cyanide (green), the atomic gas carbon atoms (blue), and the plasma gas hydrogen (pink) are reflected (Credit: ALMA (ESO/NAOJ/NRAO) , T. Izumi et al.)]
Mr. Izumi and his research team discovered an active galaxy located approximately 13 million light-years away from Earth.Compass constellation galaxy” was observed with ALMA, and the flow of gas within a few light years of the galactic center was observed. As a result, for a range of about 6 light years around the center,Succeeded in observing the flow of gas with the highest resolution ever of approximately 1 light yearDid.
The first observation was that light from the center of the galaxy was absorbed by molecular gas, creating a shadow. Detailed observations reveal that the molecular gas is moving away from the observer, which corresponds to falling toward the black hole at its center.
We also obtained observations of the momentum of the observed gas accretion disk. The momentum of the gas disk generates pressure, which supports the gas disk’s gravity, but this observation result showed that the gravity is too large to be supported by pressure. In this state, the gas disk collapses under its own gravity and forms a complex structure.Gravity is unstable”, and the gas disk changes from orbiting around the black hole to falling. This research at ALMA isThe first case in which gravitational instability was revealed through observation resultshave become.
Furthermore, the gas flow in the center was quantitatively understood from the observation results of gas density and velocity. It has now been revealed that the amount of gas falling into a black hole, calculated from the intensity of radiation from active galaxies, is only 3% of the gas density and velocity revealed by ALMA observations. Ta. In other words, the black hole is “devouring” the falling gas, with most of it flying outward.
So, how does that gas scatter? ALMA has clarified the details of gas by dividing it into three phases: molecules, atoms, and plasma. It was found that all gas phases escape from the black hole, and that the amounts of molecular gas and atomic gas are particularly large. It was also revealed that many of them are not fast enough to break through the black hole’s gravity and fly out, so they return to the accretion disk. In other words, ALMA isA “fountain” of gas appears around a supermassive black hole
I made it.
*…In this research, carbon monoxide and hydrogen cyanide were observed as molecular gases, carbon atoms were observed as atomic gases, and hydrogen was observed as plasma gas.
■Monumental achievements in supermassive black hole research
The results of this observation revealed an extremely detailed picture of the gas flow that occurs around a supermassive black hole. The dynamics around supermassive black holes and the conditions under which they suck in matter and grow are still poorly understood, and it is said that they are involved in the evolution of galaxies themselves, so it is extremely difficult to understand the details. It is important. Mr. Izumi described this result as “a monumental achievement in the history of supermassive black hole research.”
Source Takuma Izumi, et al.“Supermassive black hole feeding and feedback observed on subparsec scales”. (Science) Takuma Izumi.
“Finally elucidated! The growth mechanism of supermassive black holes and the circulation of matter at the center of galaxies”. (ALMA)
Written by Riri Aya
