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An absorption profile centred at 78 megahertz in the sky-averaged spectrum
Judd D Bowman1, Alan E E Rogers2, Raul A Monsalve1,3,4
1School of Earth and Space Exploration, Arizona State University, Tempe, Arizona 85287, USA.
Nature
|March 2, 2018
Summary
Scientists detected a radio signal distortion from early stars interacting with primordial hydrogen gas. The signal
Area of Science:
- Cosmology
- Astrophysics
- Radio Astronomy
Background:
- Early stars emitted ultraviolet light, influencing the primordial hydrogen gas.
- This interaction was expected to create an observable radio spectral distortion.
Purpose of the Study:
- To detect and analyze the spectral distortion caused by early stars in the early Universe.
- To investigate discrepancies between observed signals and theoretical predictions.
Main Methods:
- Observation of the sky-averaged radio spectrum at frequencies below 200 megahertz.
- Analysis of a detected absorption profile centered at 78 megahertz.
Main Results:
- Detection of a flattened absorption profile with specific frequency and amplitude characteristics.
- Observed amplitude was significantly higher than predicted by standard astrophysical models.
Conclusions:
- The discrepancy suggests either colder primordial gas or hotter background radiation.
- Dark matter-baryon interactions are a potential explanation for the observed signal amplitude.
- Evidence for early star formation and Lyman-α photon background by 180 million years post-Big Bang.
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