関連する実験動画
Updated: Dec 5, 2025

06:14
Simulating Imaging of Large Scale Radio Arrays on the Lunar Surface
Published on: July 30, 2020
5.2K
H I 銀河の集合体からの21センチメートルの放射は,平均赤道偏移1で
Aditya Chowdhury1, Nissim Kanekar2, Jayaram N Chengalur1
1National Centre for Radio Astrophysics, Tata Institute of Fundamental Research, Pune, India.
Nature
|October 15, 2020
まとめ
科学者は銀河の原子水素 (H I) ガス質量を赤偏移1で測定した. このガスの質量は恒星質量に似ており 恒星形成を1〜20億年しか維持できず ガス蓄積不足が宇宙の恒星形成の減少を引き起こしたことを示唆している.
科学分野:
- 銀河の宇宙進化
- 天体物理学と宇宙学
- 銀河のガス含有量
背景:
- 銀河の進化には,ガスの蓄積,星への変換,そして星形成が含まれています.
- 宇宙の恒星形成は 赤偏移1〜3でピークに達し 10億年にわたって著しく減少しました
- 遠くの銀河で原子水素 (H I) ガス質量を測定することは,信号の弱さのために困難でした.
研究 の 目的:
- 恒星形成の銀河の H I 質量の平均を測定する
- 恒星形成と銀河の進化における 原子ガスの役割を理解するために
- 宇宙の恒星形成率の減少の原因を調査する
主な方法:
- 赤道1の銀河からの 個々のH I21センチメートルの 放射信号の積み重ねを利用した.
- 1.4ギガヘルツのラジオ連続観測を用いた平均恒星形成率の推定.
- 観測された恒星形成率の燃料需要と測定されたH Iガス質量を比較した.
主要な成果:
- 赤道1の恒星形成銀河の平均H I質量は,それらの平均恒星質量と同等であることが判明した.
- 観測されたH Iガスの質量は 新鮮なガスが落ちることなく 観測された恒星形成の速度を わずか"〜20億年間 維持できるのです
- これは,赤偏移が1つ未満の銀河にガスの蓄積が不十分であったことを示唆している.
結論:
- 赤偏移1の銀河の限られた原子ガス貯蔵庫は 十分なガス蓄積を示唆している.
- この不十分なガスの蓄積は,赤偏移が1未満で宇宙の恒星形成率の密度が低下した可能性があります.
- 銀河の進化を完全に理解するには ガス崩壊を理解することが重要です
関連する概念動画
Emission Spectra
74.6K
When solids, liquids, or condensed gases are heated sufficiently, they radiate some of the excess energy as light. Photons produced in this manner have a range of energies, and thereby produce a continuous spectrum in which an unbroken series of wavelengths is present.
74.6K
Atomic Emission Spectroscopy: Lab
450
AES is a powerful analytical technique, especially effective when used with plasma sources, producing abundant spectra in characteristic emission lines. The Inductively Coupled Plasma (ICP), in particular, yields superior quantitative analytical data due to its high stability, low noise, low background, and minimal interferences under optimal experimental conditions. However, newer air-operated microwave sources are emerging as promising alternatives that could be more cost-effective than...
450
Atomic Emission Spectroscopy: Overview
3.2K
Atomic emission spectroscopy (AES) is an analytical technique used to determine the elemental composition of a sample by analyzing the light emitted from excited atoms. In AES, atoms in a sample are excited to higher energy levels by thermal energy from high-temperature sources, such as plasma, arcs, or sparks. When these excited atoms return to lower energy states, they emit light at specific wavelengths characteristic of each element. The resulting atomic emission spectrum, which consists of...
3.2K
Super-resolution Fluorescence Microscopy
12.0K
Super-resolution fluorescence microscopy (SRFM) provides a better resolution than conventional fluorescence microscopy by reducing the point spread function (PSF). PSF is the light intensity distribution from a point that causes it to appear blurred. Due to PSF, each fluorescing point appears bigger than its actual size, and it is the PSF interference of nearby fluorophores that causes the blurred image. Various approaches to achieving higher resolution through SRFM have recently been...
12.0K
Flame Photometry: Lab
686
In a flame photometer, when a solution like potassium chloride is aspirated into the flame, the solvent evaporates, leaving behind dehydrated salt. This salt dissociates into free gaseous atoms in their ground state. Some of these atoms absorb energy from the flame, leading to their excitation. The excited atoms return to the ground state, emitting photons at characteristic wavelengths. Because only electronic transitions are involved, the resulting emission lines are very narrow. The intensity...
686
Detection of Black Holes
2.4K
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...
2.4K

