関連する実験動画
Updated: Apr 30, 2026

10:52
Direct Imaging of Laser-driven Ultrafast Molecular Rotation
Published on: February 4, 2017
9.5K
回転する中性子星からの一時的なラジオバースト
M A McLaughlin1, A G Lyne, D R Lorimer
1Jodrell Bank Observatory, University of Manchester, Macclesfield, Cheshire SK11 9DL, UK. Maura.McLaughlin@manchester.ac.uk
Nature
|February 17, 2006
まとめ
天文学者は,短時間,分散した電波を放射する11の新しいラジオ源を発見しました. これらの急速な無線信号は,我々の銀河系に新種の回転中性子星が存在することを示唆している.
科学分野:
- 天文学と天体物理学について
- ラジオ天文学 ラジオ天文学
- 中性子星物理学 中性子星物理学
背景:
- ラジオ空は,高い潜在能力にもかかわらず,一時的な信号のためにほとんど未探査のままです.
- 最近の発見は,これまで未知の変数放射源を分から時間スケールで強調しています.
研究 の 目的:
- より短い時間スケール (ミリ秒) で一時的な行動を示す無線源を検索し,特徴づけます.
- 新しく発見されたこれらの短命な無線源の性質と人口を調査する.
主な方法:
- 急速無線トランジエントの捜索を行いました.
- 周期性を特定するためにバスト到着時間を分析しました.
- 測定されたパルス周期の変化と,選択されたソースの磁場強度推論.
主要な成果:
- 2〜30 msの単一の分散した爆発を持つ11個のオブジェクトを検出しました.
- 10つの情報源で周期性 (0.4〜7秒) を特定し,旋回中性子星の存在を示唆した.
- 1つの源に対して高い磁場強度 (5 x 10^13 G) を推論した.
結論:
- 発見された光源は,一時的な,潜在的に回転する中性子星の新しい集団を表しています.
- この集団は,電磁スペクトル全体で観測された,孤立した中性子星の他のクラスに関連している可能性があります.
- これらの光源の銀河の総数は,既知の電波パルサーの総数を上回る可能性が高い.
関連する概念動画
Nuclear Transmutation
12.9K
Nuclear transmutation is the conversion of one nuclide into another. It can occur by the radioactive decay of a nucleus, or the reaction of a nucleus with another particle. The first manmade nucleus was produced in Ernest Rutherford’s laboratory in 1919 by a transmutation reaction, the bombardment of one type of nuclei with other nuclei or with neutrons. Rutherford bombarded nitrogen-14 atoms with high-speed α particles from a natural radioactive isotope of radium and observed...
12.9K
Atomic Nuclei: Larmor Precession Frequency
3.5K
The earth's gravitational field produces a 'twisting force' perpendicular to the angular momentum of a spinning mass (such as a spinning top) that causes the mass to 'wobble' around the gravitational field axis in a phenomenon called precession. Similarly, the magnetic moment (μ) of a spinning nucleus precesses due to an external magnetic field directed along the z-axis. The precession of the magnetic moment vector about the magnetic field is called Larmor precession,...
3.5K
Atomic Nuclei: Magnetic Resonance
1.2K
The number of nuclear spins aligned in the lower energy state is slightly greater than those in the higher energy state. In the presence of an external magnetic field, as the spins precess at the Larmor frequency, the excess population results in a net magnetization oriented along the z axis. When a pulse or a short burst of radio waves at the Larmor frequency is applied along the x axis, the coupling of frequencies causes resonance and flips the nuclear spins of the excess population from the...
1.2K
Atomic Nuclei: Nuclear Relaxation Processes
1.1K
In the absence of an external magnetic field, nuclear spin states are degenerate and randomly oriented. When a magnetic field is applied, the spins begin to precess and orient themselves along (lower energy) or against (higher energy) the direction of the field. At equilibrium, a slight excess population of spins exists in the lower energy state. Because the direction of the magnetic field is fixed as the z-axis, the precessing magnetic moments are randomly oriented around the z-axis.
1.1K
NMR Spectrometers: Radiofrequency Pulses and Pulse Sequences
1.8K
A pulse is a short burst of radio waves distributed over a range of frequencies that simultaneously excites all the nuclei in the sample. Upon passing a radio frequency pulse along the x-axis, the nuclei absorb energy corresponding to their Larmor frequencies and achieve resonance. This shifts the net magnetization vector from the z-axis toward the transverse plane. This angle of rotation of the magnetization vector, or the flip angle, is proportional to the duration and intensity of the pulse.
1.8K
Atomic Nuclei: Types of Nuclear Relaxation
1.1K
Nuclear relaxation restores the equilibrium population imbalance and can occur via spin–lattice or spin–spin mechanisms, which are first-order exponential decay processes.
In spin–lattice or longitudinal relaxation, the excited spins exchange energy with the surrounding lattice as they return to the lower energy level. Among several mechanisms that contribute to spin–lattice relaxation, magnetic dipolar interactions are significant. Here, the excited nucleus transfers...
In spin–lattice or longitudinal relaxation, the excited spins exchange energy with the surrounding lattice as they return to the lower energy level. Among several mechanisms that contribute to spin–lattice relaxation, magnetic dipolar interactions are significant. Here, the excited nucleus transfers...
1.1K

