Journal Article

Correlations between 21-cm radiation and the cosmic microwave background from active sources

Aaron Berndsen, Levon Pogosian and Mark Wyman

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 407, issue 2, pages 1116-1122
Published in print September 2010 | ISSN: 0035-8711
Published online September 2010 | e-ISSN: 1365-2966 | DOI:

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Neutral hydrogen is ubiquitous, absorbing and emitting 21-cm radiation throughout much of the Universe's history. Active sources of perturbations, such as cosmic strings, would generate simultaneous perturbations in the distribution of neutral hydrogen and in the cosmic microwave background (CMB) radiation from recombination. Moving strings would create wakes leading to 21-cm brightness fluctuations, while also perturbing CMB light via the Gott–Kaiser–Stebbins effect. This would lead to spatial correlations between the 21-cm and CMB anisotropies. Passive sources, like inflationary perturbations, predict no cross-correlations prior to the onset of reionization. Thus, observation of any cross-correlation between CMB and 21-cm radiation from dark ages would constitute evidence for new physics. We calculate the cosmic string-induced correlations between CMB and 21-cm radiation and evaluate their observability.

Keywords: cosmic background radiation; cosmology: observations; dark ages, reionization, first stars; large scale structure of Universe

Journal Article.  5493 words.  Illustrated.

Subjects: Astronomy and Astrophysics