Detectability of the 21-cm CMB cross-correlation from the epoch of reionization

Hiroyuki Tashiro, Nabila Aghanim, Mathieu Langer, Marian Douspis, Saleem Zaroubi, Vibor Jelic

Research output: Contribution to journalArticlepeer-review


The 21-cm line fluctuations and the cosmic microwave background (CMB) are powerful probes of the epoch of reionization of the Universe. We study the potential of the cross-correlation between 21-cm line fluctuations and CMB anisotropy to obtain further constraints on the reionization history. We analytically compute the 21-cm cross-correlation with the CMB temperature anisotropy and polarization, and we calculate the signal-to-noise ratio (S/N) for its detection with together with LOw Frequency ARray (LOFAR), Murchison Widefield Array (MWA) and Square Kilometer Array (SKA). We find, on the one hand, that the 21-cm cross-correlation signal with CMB temperature from the instant reionization can be detected with an S/N of ∼2 for LOFAR and ∼10 for SKA. On the other hand, we confirm that the detection of the 21-cm cross-correlation with CMB polarization is practically infeasible.

Original languageEnglish
Pages (from-to)2617-2625
Number of pages9
JournalMonthly Notices of the Royal Astronomical Society
Issue number4
StatePublished - Mar 2010
Externally publishedYes


  • Cosmic microwave background
  • Cosmology: theory
  • Large-scale structure of Universe


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