Three-dimensional distribution of molecular & atomic hydrogen in galaxies
- Category
Science & Technology
- Published
1st Jun, 2021
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A researcher has estimated the three-dimensional distribution of molecular and atomic hydrogen in a nearby galaxy which can help lead to clues to the star formation processes and the evolution of the galaxy.
Context
A researcher has estimated the three-dimensional distribution of molecular and atomic hydrogen in a nearby galaxy which can help lead to clues to the star formation processes and the evolution of the galaxy.
- The research was conducted at Raman Research Institute (RRI), Bengaluru, an autonomous organisation of the Department of Science and Technology (DST), Government of India.
- It was funded by the DST, Government of India.
Key Features of the Study
- The estimates are based on the phenomenon of the galaxies like, the Milky Way, which consists of discs containing stars, molecular and atomic hydrogen, and helium.
- The estimation was carried out by mathematical calculations on the computer and used publicly available data.
- Study: Under the study a single galaxy about 20 million light-years away from the Milky Way was focused.
- The spectral lines of carbon monoxide (CO) were studied to accurately trace molecular hydrogen, whose spectral lines are more difficult to observe.
What are Spectral lines?
- These are narrow emission or absorption features in the spectra of gaseous and ionized sources.
- Spectral lines are powerful diagnostics of physical and chemical conditions in astronomical objects.
- Their rest frequencies identify the specific atoms and molecules involved, and their Doppler shifts measure radial velocities.
- These velocities yield the redshifts and Hubble distances of extragalactic sources, plus rotation curves and radial mass distributions for resolved galaxies.
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- Spectral lines of the CO molecule are used to infer the three-dimensional distribution of both the narrow disc component and the diffuse component of molecular hydrogen.
What is the role of Molecular Hydrogen gas in star formation?
- The molecular hydrogen gas converts to individual stars under the pull of gravity, thus holding clues to the star formation processes and the evolution of the galaxy.
- The atomic hydrogen extends both above and below the discs.
- It has also been estimated that molecular hydrogen extends farther from the disc in both directions, up to about 3000 light-years.
- This gaseous component is warmer than the one straddling the disc and has comparatively lesser densities. This is known as the ‘diffuse’ component of the molecular disc.
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What are the outcomes of the study?
- The research says that the extension of gas may explain the occurrence of stars at a few thousand light-years perpendicular to the galactic disc.
- Research found that the diffuse component makes up about 70 percent of the molecular hydrogen, and this fraction remains roughly constant along the radius of the disc.