銀河団の衝突におけるダークマターの非重力相互作用
David Harvey1, Richard Massey2, Thomas Kitching3
1Laboratoire d'Astrophysique, École Polytechnique Fédérale de Lausanne, Observatoire de Sauverny, 1290 Versoix, Switzerland. Royal Observatory, University of Edinburgh, Blackford Hill, Edinburgh EH9 3HJ, UK. david.harvey@epfl.ch.
Science (New York, N.Y.)
|March 28, 2015
まとめ
銀河団の衝突は暗黒物質の性質を明らかにする. 72の衝突の新しい分析は,暗黒物質の自己相互作用が限られていることを示し,標準モデルを超えた理論を制限しています.
科学分野:
- 天体物理学 天体物理学
- コスモロジー・コスモロジーとは
- 素粒子物理学 素粒子物理学について
背景:
- 銀河団の衝突は,暗黒物質の基本的な性質についてのユニークな洞察を提供します.
- 弾丸星団のような以前の観測は,遠距離力に対する暗黒物質の自己相互作用の断面を制限しました.
研究 の 目的:
- ダークマターの自己相互作用の制約を洗練するために,より大きな銀河団衝突 (72イベント) のサンプルを統計的に分析する.
- ダークマターに作用する非重力力をテストするために,衝突時にダークマターの振る舞いを調べます.
主な方法:
- チャンドラ宇宙望遠鏡とハッブル宇宙望遠鏡のデータを活用して,大・小の両方の合併を含む72の銀河団の衝突を観測した.
- これらの観測を統計的に組み合わせて,暗黒物質の位置と性質を正確に決定した.
主要な成果:
- 7.6シグマの統計的有意性を持つダークマスの存在が確認されました.
- 暗黒質量が関連星と密接に並んでいる (5.8 ± 8.2 キロパーセク以内) ことを発見した.
- 質量単位あたりの暗黒物質の自己相互作用の横断面の厳格な上限を導き出した: 95%の信頼レベルで σ (((DM) /m < 0.47 cm (((2) /g.
結論:
- 衝突する星団の恒星と暗黒物質の観測された配列は,その自己相互作用の断面を大幅に制限する.
- これらの発見は,より強い暗黒物質の自己相互作用を予測する粒子物理学の標準モデルへの特定の提案された拡張を否定しています.
関連する概念動画
01:24Comparison Between Electrical And Gravitational Forces
4.4K
There are four fundamental forces in nature: the gravitational force, the electromagnetic force, the strong nuclear force, and the weak nuclear force. To compare the numerical strengths of the first two, take two particles of the same kind. Since electrons are fundamental particles, they are a good example.
Since both are inverse square law forces, the distance gets canceled when the ratio of the two forces is considered. Instead, the ratio of the electrical and gravitational forces depends on...
Since both are inverse square law forces, the distance gets canceled when the ratio of the two forces is considered. Instead, the ratio of the electrical and gravitational forces depends on...
4.4K
01:10Detection of Black Holes
2.6K
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...
2.6K
01:15Newton's Law of Gravitation
18.0K
Our everyday observation tells us that all objects close to the Earth naturally tend to fall to the ground. Early philosophers assumed that this downward force was unique to Earth. By the 16th century, Nicolaus Copernicus (1473-1543) put forward the heliocentric theory, which suggested that Earth and other planets orbited the sun, while the Moon orbited the Earth. However, it was Isaac Newton (1642-1727) who linked these two motions together in the 17th century. He reasoned that the force of...
18.0K
01:21Schwarzschild Radius and Event Horizon
3.1K
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...
3.1K
01:05Collisions in Multiple Dimensions: Introduction
7.5K
It is far more common for collisions to occur in two dimensions; that is, the initial velocity vectors are neither parallel nor antiparallel to each other. Let's see what complications arise from this. The first idea is that momentum is a vector. Like all vectors, it can be expressed as a sum of perpendicular components (usually, though not always, an x-component and a y-component, and a z-component if necessary). Thus, when the statement of conservation of momentum is written for a...
7.5K
01:24Newton's Law of Gravitational Attraction
1.9K
Sir Isaac Newton established the universality of the law of gravitational attraction based on empirical evidence and inductive reasoning. He published his work in Philosophiae Naturalis Principia Mathematica ("the Principia") on July 5, 1687.
Newton's law of gravitational attraction is a fundamental law of physics that governs the attraction between objects. It states that the magnitude of the gravitational force between any two objects is proportional to their masses and inversely...
Newton's law of gravitational attraction is a fundamental law of physics that governs the attraction between objects. It states that the magnitude of the gravitational force between any two objects is proportional to their masses and inversely...
1.9K