Intergalactic heating by Lyman-alpha photons including hyperfine structure corrections

Abstract

Lyman-alpha photons from the first radiating sources in the Universe play a pivotal role in 21-cm radio detections of Cosmic Dawn and the Epoch of Reionization. Comments are provided on the effect of the hyperfine structure of hydrogen on the rate of heating or cooling of the Intergalactic Medium. It is shown that heating of the still neutral hydrogen by the Cosmic Microwave Background is negligible, with a characteristic heating time of 1e27 s/ (1+z) at redshift z.

arXiv commentAccepted for publication in Research Notes of the AAS. (Missing reference added.)

References in corpus (6)

• 21-cm Tomography of the Intergalactic Medium at High Redshift
• Wouthuysen-Field coupling strength and application to high-redshift 21 cm radiation
• The Spin-Kinetic Temperature Coupling and the Heating Rate due to Lyman Alpha Scattering before Reionization: Predictions for 21cm Emission and Absorption
• UV pumping of hyperfine transitions in the light elements, with application to 21-cm hydrogen and 92-cm deuterium lines from the early universe
• The Spin-Resolved Atomic Velocity Distribution and 21-cm Line Profile of Dark-Age Gas
• Energy transfer by the scattering of resonant photons

Cited by in corpus (3)

• HERA Phase I Limits on the Cosmic 21-cm Signal: Constraints on Astrophysics and Cosmology During the Epoch of Reionization
• Measuring the cosmic expansion rate using 21-cm velocity acoustic oscillations
• Constraining exotic dark matter models with the dark ages 21-cm signal