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تسجيل مستخدم جديدThe cross-correlation of the CMB polarisation and the 21-cm line fluctuations from cosmic reionisation
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The cosmic microwave background (CMB) polarisation and the 21 cm line fluctuations are powerful probes of cosmological reionisation. We study how the cross-correlation between the CMB polarisation (E-modes) and the 21 cm line fluctuations can be used to gain further understanding of the reionisation history, within the framework of inhomogeneous reionisation. Since the E-mode polarisation reflects the amplitude of the quadrupole component of the CMB temperature fluctuations, the angular power spectrum of the cross-correlation exhibits oscillations at all multipoles. The first peak of the power spectrum appears at the scale corresponding to the quadrupole at the redshift that is probed by the 21 cm line fluctuations. The peak reaches its maximum value in redshift when the average ionisation fraction of the universe is about half. On the other hand, on small scales, there is a damping that depends on the duration of reionisation. Thus, the cross-correlation between the CMB polarisation and the 21 cm line fluctuations has the potential to constrain accurately the epoch and the duration of reionisation.
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In this letter, 21 cm intensity maps acquired at the Green Bank Telescope are cross-correlated with large-scale structure traced by galaxies in the WiggleZ Dark Energy Survey. The data span the redshift range 0.6 < z < 1 over two fields totaling ~41
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Tapomoy Guha Sarkar
, Kanan K. Datta
, Somnath Bharadwaj (Indiann Institute of Technology
2009
The late-time growth of large scale structures (LSS) is imprinted in the CMBR anisotropy through the Integrated Sachs Wolfe (ISW) effect. This is perceived to be a very important observational probe of dark energy. Future observations of redshifted 2
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