English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The thermal evolution of the cosmic gas decoupled from that of the cosmicmicrowave background (CMB) at a redshift z~200. Afterwards and before the firststars had formed, the cosmic neutral hydrogen absorbed the CMB flux at itsresonant 21cm spin-flip transition. We calculate the evolution of the spintemperature for this transition and the resulting anisotropies that areimprinted on the CMB sky due to linear density fluctuations during this epoch.These anisotropies at an observed wavelength of 10.56[(1+z)/50] meters, containan amount of information that is orders of magnitude larger than any othercosmological probe. Their detection, although challenging, could tightlyconstrain any possible running of the spectral index from inflation (assuggested by WMAP), small deviations from Gaussianity, or any significantcontribution from neutrinos or warm dark matter to the cosmic mass budget.Comment: 4 pages, 3 figures, accepted for publication in Physical Review  Letter

Measuring the Small-Scale Power Spectrum of Cosmic Density Fluctuations through 21 cm Tomography Prior to the Epoch of Structure Formation