球状星団M22の2つの恒星質量ブラックホール
Jay Strader1, Laura Chomiuk, Thomas J Maccarone
1Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA. strader@pa.msu.edu
Nature
|October 6, 2012
まとめ
M22球状星団で2つの恒星質量ブラックホールが発見され,射出理論に挑戦しました. この発見は,球状星団がこれまで考えられていたよりも多くのブラックホールを保持している可能性があることを示唆しています.
科学分野:
- 天文学 天文学
- 天体物理学 天体物理学
- 恒星力学 恒星力学とは
背景:
- 球状星団は,ダイナミックな相互作用により,ほとんどの恒星質量ブラックホールを放出すると予測されています.
- 銀河系の球状星団で観測されたブラックホール/X線バイナリの希少性は,この放出仮説を裏付けている.
- 以前の銀河系外球状星団におけるブラックホールの検出では,質量の決定が欠け,中等質量のブラックホールである可能性がある.
研究 の 目的:
- 銀河系球状星団M22内のコンパクトな天体の存在と性質を調査する.
- 球状星団の恒星質量ブラックホールの集団と動態に関する理論的予測を検証する.
主な方法:
- M22球状星団内のフラットスペクトルの無線源の検出と分析.
- ラジオとX線流量比分析により,収縮するオブジェクトの特徴を特定する.
- 球状星団におけるブラックホールの理論モデルと観測された性質の比較.
主要な成果:
- 球状星団M22の2つの増加中の恒星質量ブラックホール (それぞれ約10〜20太陽質量) の特定.
- これらのブラックホールの高周波対X線流量比の観測は,クラスター環境で予測されるより大きな質量と一致しています.
- 球状星団からのブラックホールの放出は,ほとんどのモデルが予測するよりも効率が低いことを示唆する証拠があります.
結論:
- M22球状星団には,星質量5~100個のブラックホールの有意な集団が宿っている可能性が高い.
- これらのブラックホールの存在は,ダイナミックな加熱によるM22の大きな核半径を説明する可能性がある.
- この発見は,ブラックホールの保持と球状星団内の動態に関するモデルの見直しを必要とします.
関連する概念動画
01:54Molar Mass
65.5K
The identity of a substance is defined not only by the types of atoms or ions it contains but by the quantity of each type of atom or ion. For example, water, H2O, and hydrogen peroxide, H2O2, are alike in that their respective molecules are composed of hydrogen and oxygen atoms. However, because a hydrogen peroxide molecule contains two oxygen atoms, as opposed to the water molecule, which has only one, the two substances exhibit very different properties.
65.5K
01:27Gravity between Spherical Bodies
7.2K
Newton's law of gravitation describes the gravitational force between any two point masses. However, for extended spherical objects like the Earth, the Moon, and other planets, the law holds with an assumption that masses of spherical objects are concentrated at their respective centers.
This assumption can be proved easily by showing that the expression for gravitational potential energy between a hollow sphere of mass (M) and a point mass (m) is the same as it would be for a pair of extended...
This assumption can be proved easily by showing that the expression for gravitational potential energy between a hollow sphere of mass (M) and a point mass (m) is the same as it would be for a pair of extended...
7.2K
01:21Schwarzschild Radius and Event Horizon
2.2K
No object with a finite mass can travel faster than the speed of light in a vacuum. This fact has an interesting consequence in the domain of extremely high gravitational fields.
The minimum speed required to launch a projectile from the surface of an object to which it is gravitationally bound so that it eventually escapes the object’s gravitational field is called the escape velocity. The escape velocity is independent of the mass of the object. Merging the idea of escape...
The minimum speed required to launch a projectile from the surface of an object to which it is gravitationally bound so that it eventually escapes the object’s gravitational field is called the escape velocity. The escape velocity is independent of the mass of the object. Merging the idea of escape...
2.2K
01:10Detection of Black Holes
1.7K
Although black holes were theoretically postulated in the 1920s, they remained outside the domain of observational astronomy until the 1970s.
Their closest cousins are neutron stars, which are composed almost entirely of neutrons packed against each other, making them extremely dense. A neutron star has the same mass as the Sun but its diameter is only a few kilometers. Therefore, the escape velocity from their surface is close to the speed of light.
Not until the 1960s, when the first neutron...
Their closest cousins are neutron stars, which are composed almost entirely of neutrons packed against each other, making them extremely dense. A neutron star has the same mass as the Sun but its diameter is only a few kilometers. Therefore, the escape velocity from their surface is close to the speed of light.
Not until the 1960s, when the first neutron...
1.7K
01:14Gravitation Between Spherically Symmetric Masses
1.5K
The gravitational potential energy between two spherically symmetric bodies can be calculated from the masses and the distance between the bodies, assuming that the center of mass is concentrated at the respective centers of the bodies.
1.5K
01:12Reduced Mass Coordinates: Isolated Two-body Problem
2.5K
In classical mechanics, the two-body problem is one of the fundamental problems describing the motion of two interacting bodies under gravity or any other central force. When considering the motion of two bodies, one of the most important concepts is the reduced mass coordinates, a quantity that allows the two-body problem to be solved like a single-body problem. In these circumstances, it is assumed that a single body with reduced mass revolves around another body fixed in a position with an...
2.5K