Abstract
We present a theoretical estimate for a new observable: the cross correlation between the Lyman-α flux fluctuations in quasar spectra and the convergence of the cosmic microwave background as measured along the same line of sight. As a first step toward the assessment of its detectability, we estimate the signal-to-noise ratio using linear theory. Although the signal-to-noise is small for a single line of sight and peaks at somewhat smaller redshifts than those probed by the Lyman-α forest, we estimate a total signal-to-noise of 9 for cross correlating quasar spectra of SDSS-III with Planck and 20 for cross correlating with a future polarization based cosmic microwave background experiment. The detection of this effect would be a direct measure of the neutral hydrogen-matter cross correlation and could provide important information on the growth of structures at large scales in a redshift range which is still poorly probed.
Original language | English (US) |
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Article number | 091304 |
Journal | Physical review letters |
Volume | 103 |
Issue number | 9 |
DOIs | |
State | Published - Aug 28 2009 |
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)