More and more binary star mergers were discovered during the observation of the scoper
The latest study on black hole mergers suggests that black holes in binary black hole systems typically have similar masses — suggesting that binary black hole systems most likely evolved from "massive star pairs."
With the operation of the Laser Interferometer Gravitational Wave Observatory (LIGO) and the Virgo Interferometer (a large gravitational wave detector near Pisa, Italy), more and more black hole mergers have been discovered. People are starting to wonder: What do these merging black holes have in common? Or is their merger purely accidental?
Pictured above is a simulated image of a black hole merger (orthopedic), and LIGO shows that they detected ten double-black hole mergers in their first two observations.
Image source: "SXS Lensing"
The binary black hole system and its origins
The causes of binary black hole systems (BBHs) are inconclusive, and the phenomenon that black hole masses in the system tend to be higher than expected makes the origin of binary black hole systems more complicated. Some astronomers believe that the binary black hole system is the product of a massive binary star system, while others have proposed the hypothesis that black holes in dense star populations meet and pair with each other. Another possibility is that black holes in binary black hole systems formed in the early universe — thus skipping stellar forms and eventually forming binary black hole systems.
The image above shows the artist's depiction of the merging process of two black holes
Image source: T Pyle (from LIGO)
Studying binary black hole mergers is a great way to explore the composition of binary black holes. Gravitational waves produced during a black hole merger contain parameters (e.g., mass) about the composition of two black holes. The Laser Interferometer Gravitational Wave Observatory and the Virgo Interferometer detected 10 binary black hole mergers in their first two observations, with black hole masses ranging from 18 to 84 solar masses.
In a new study, Maya Fishbach and Daniel Holz of the University of Chicago explored the effects of the masses of two black holes in the system on their pairing mechanism. They found something interesting – the common denominator of black holes in binary black hole systems may be far greater than one might expect!
Possible pairing mechanisms
Fishbach and Holz attempt to understand the binary black hole pairing mechanism through differences in the distribution of black hole masses, dividing it into three cases:
The mass distribution in a binary black hole system is only affected by the largest and least massive black holes in the system.
The distribution of black hole mass in a binary black hole system depends on the largest and least massive black holes and the mass ratio of the two black holes in the system.
The distribution of black hole mass in a binary black hole system depends on the distribution of the maximum and least massive black holes, the mass ratio between the two black holes, and the total mass of the binary black hole system.
The blue marker above shows the estimated mass of the binary black hole system detected by the Laser Interferometer Gravitational-Wave Observatory (LIGO) in the previous two observations (regardless of uncertainty). If uncertainty is taken into account, all 10 binary black hole systems observed by the Laser Interferometer Gravitational-Wave Observatory (LIGO) all have the same component masses.
Source: LIGO-Virgo/Frank Elavsky/Northwestern U.
Fishbach and Holz made two major discoveries after modeling the above three hypotheses on observations of the 10 binary black hole merger processes: Random pairing is almost impossible. 2. Black holes in binary black hole systems are five times more likely to have similar masses than in other situations.
Models that eventually form similar mass binary black hole systems usually evolve from massive binary star models. Of course, this does not mean that other mechanisms of binary black hole system formation can be excluded, fishbach and Holz research show that future models may need to take into account the mass ratio of two black holes in a binary black hole system.
Of course, the study is based on data on only ten binary black hole mergers, and as more observations are made at the Laser Interferometer Gravitational-Wave Observatory and the Virgo Interferometer, astronomers will soon be able to obtain more observations and unravel the mystery of how the binary black hole system was formed.
BY: AAS NOVA
FY: Milo_Guo
If there is any infringement of the relevant content, please contact the author to delete it after the work is published
Please also obtain authorization to reprint, and pay attention to maintaining completeness and indicating source