nLab cosmic microwave background radiation

Idea

(…)

Properties

Hydrogen line

It has been argued (Higan-Rees 79) that observation of a absorption at the 21cm hydrogen line in the cosmic microwave background would be a signal from the time when the first stars? formed and ignited, a cosmological epoch not otherwise accessible to observation. A claim of detection of this signal by the EDGES experiment appeared in BRMMM 18.

Related concepts

• cosmology, standard model of cosmology

• inhomogeneous cosmology

• dark radiation

• hydrogen line

References

General

Lecture notes includes

• Daniel Baumann, from section 3 on in TASI Lectures on Primordial Cosmology (arXiv:1807.03098)

See also the references at cosmic inflation.

See also

• Wikipedia, Cosmic microwave backround radiation

On the hydron line

• C. J. Hogan, Martin Rees, Spectral appearance of non-uniform gas at high $z$, Monthly Notices of the Royal Astronomical Society, Volume 188, Issue 4, 1 October 1979, Pages 791–798 (doi:10.1093/mnras/188.4.791)

A claim of detection of the cosmological signal by the EDGES experiment is due to

• Judd D. Bowman, Alan E. E. Rogers, Raul A. Monsalve, Thomas J. Mozdzen, Nivedita Mahesh, An absorption profile centred at 78 megahertz in the sky-averaged spectrum, Nature volume 555, pages 67–70 (01 March 2018) (doi:10.1038/nature25792)

Discussion of this claim incluces

• Adam Falkowski, 21cm to dark matter, March 2018

Applying topological data analysis/persistent homology to the CMB in search for signatures of inhomogeneous cosmology:

• Pratyush Pranav, Thomas Buchert, Homology reveals significant anisotropy in the cosmic microwave background (arXiv:2308.10738)