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Updated: Sep 22, 2025
09:40
Measurement and Analysis of Atomic Hydrogen and Diatomic Molecular AlO, C2, CN, and TiO Spectra Following Laser-induced Optical Breakdown
Published on: February 14, 2014
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Resolving the H I in damped Lyman α systems that power star formation
Rongmon Bordoloi1, John M O'Meara2, Keren Sharon3
1Department of Physics, North Carolina State University, Raleigh, NC, USA. rbordol@ncsu.edu.
Nature
|May 18, 2022
Summary
Damped Lyman-alpha systems, reservoirs of dense gas, were found to be larger than 238,000 square kilometers. These systems contain significant neutral hydrogen, fueling future star formation in early galaxies.
Area of Science:
- Cosmic gas reservoirs
- Early universe galaxy formation
- Astrophysical spectroscopy
Background:
- Dense atomic gas, primarily hydrogen, constitutes 90% of neutral gas at redshift 3.
- Damped Lyman-alpha systems (DLAs) absorb specific photons, studied via background quasars and gamma-ray bursts.
- Previous studies lacked constraints on the physical extent of DLAs.
Purpose of the Study:
- To determine the physical extent and properties of damped Lyman-alpha systems.
- To investigate the neutral hydrogen content and mass of these early cosmic structures.
- To assess their role in fueling subsequent star formation.
Main Methods:
- Integral-field spectroscopy of a gravitationally lensed galaxy at redshift 2.7.
- Analysis of two foreground damped Lyman-alpha systems.
- Measurement of system extent, neutral hydrogen column densities, and total mass.
Main Results:
- Two DLAs were identified with extents greater than 238,000 square kilometers.
- Neutral hydrogen column densities varied significantly on small scales (<3 kiloparsecs).
- Mean column densities ranged from 10^20.46 to 10^20.84 cm^-2, with masses exceeding 5.5x10^8 to 1.4x10^9 solar masses.
Conclusions:
- DLAs are physically large structures, significantly larger than previously inferred.
- These systems possess substantial neutral hydrogen reservoirs, indicating ample fuel for star formation.
- The findings support the role of DLAs in the evolution of massive, low-luminosity primeval galaxies at high redshifts.
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