Confirmation of a black hole with an estimated mass of ‘32.7 billion suns’ using gravitational lensing | Sorae Portal site to space

「supermassive black hole (A supermassive black hole is an extremely massive black hole that is said to be at the center of most galaxies. It is estimated that even a small cluster has a mass of several hundred thousand times the mass of the Sun, and a large mass exceeds 10 billion times.

However, the nature of supermassive black holes remains largely unknown. One reason for this is the lack of direct or indirect observational data for supermassive black holes.

Most black holes rely on estimating even the most basic information about an astronomical object, that is, the value of its mass. For example, the Sagittarius A* supermassive black hole at the center of the Milky Way is estimated to be 4.3 million times the mass of the Sun. This is unusual because it is a black hole so close to us that it can be calculated from the stars orbiting it. The masses of most supermassive black holes are estimated primarily from the total mass of the galaxies containing the black holes, and from the energy radiated from the galactic center and the properties of the spectral lines. However, neither has observed a supermassive black hole itself, and its estimation model is incomplete, so only very fuzzy numbers are calculated.

against this background,Abel 1201 BCGThe galaxy named Abell 1201 BCG is one of the few galaxies in which the mass of a supermassive black hole can be measured directly. At Abel 1201 BCG, which is about 2.7 billion light-years away, recent observations have detected an arc-shaped structure. This is because Abel 1201 BCGgravitational lens effectIt is believed to be caused by light bending and distorting the image of the galaxy behind Abel 1201 BCG as seen from Earth.

Gravitational lensing is an effect predicted by general relativity in which gravity warps space-time, and it is possible to calculate how light bends. The arc-shaped structures of Abel 1201 BCG are the result of extremely narrow radii and massive objects whose density can only be explained by supermassive black holes.

advertisement

A preliminary analysis in 2017 estimated that the supermassive black hole in Abel 1201 BCG has a mass of about 13 billion times that of the Sun. However, at the time, we were unable to obtain high-resolution images of the arc-shaped structure, nor were we able to estimate the amount and distribution of other gravitational sources such as stars and dark matter in galaxies. Therefore, there was a problem that the accuracy was not very high.

▲ Figure 2: Observation image of Abell 1201 BCG. The differences between top and bottom indicate observations at different wavelengths. The middle row is an image with the main body of Abell 1201 BCG removed by subtraction, and the remaining arc-shaped structure is a distorted image of the galaxy behind Abell 1201 BCG due to gravitational lensing (Credit: Nightingale, et al.)]

A research team led by JW Nightingale of Durham University re-observed and analyzed the Abel 1201 BCG to improve this situation.

First, the research team found that the Hubble Space Telescopewide field camera 3 (WFC3/UVIS) “For a total of 5 observations with an exposure time of 7150 seconds, new images of Abel 1201 BCG were obtained in ultraviolet and visible light. Next, the UK Integrated Supercomputing Facility”Dirac(Distributed Research Using Advanced Computing) “Gravitational Lensing Model Program”Biotulines biotulinesIt was analyzed by a supercomputer.

The analysis using DiRAC is to verify the model that matches the image captured by the Hubble Space Telescope by running hundreds of thousands of simulations that assume the existence of galaxies with different masses and positions of supermassive black holes. This method allows us to estimate the mass of the supermassive black hole at the center of Abel 1201 BCG.

Verification result, the model that best matches the pictured,The Abel 1201 BCG supermassive black hole is about 32.7 billion times the mass of the Sun (between 11.5 billion and 51.9 billion times)It has been estimated. This mass value indicates that the Abel 1201 BCG supermassive black hole isThe most massive black hole was discovered without resorting to indirect estimation methods such as radiative energymean to be

Even under the unrealistic assumption that there is no black hole at the center of Abel 1201 BCG and no bright objects, the upper limit for the mass of matter in the center is estimated to be 53 billion times the mass of the Sun. The fact that the calculation results for the model based on different assumptions showed almost the same upper bound also validates the computation model.

advertisement

On the other hand, the findings of this research raise questions about conventional wisdom. Based on the results of observations so far, it is said that there is a correlation between the mass of supermassive black holes and the speed of movement of celestial bodies in the galaxy. However, from the results of this observation, it was also found that the mass of the Abel 1201 BCG supermassive black hole is a value that deviates significantly from the correlation.

In recent years, in galaxies in which the masses of supermassive black holes have been observed in detail, the number of incoherent values ​​like these is increasing. The traditional idea of ​​estimating the mass of a supermassive black hole from the speed of a celestial body’s motion may need to be revised.

source

Text: Rare Aya