First detection of cosmic microwave background lensing and Lyman- α forest bispectrum

Cyrille Doux, Emmanuel Schaan, Eric Aubourg, Ken Ganga, Khee Gan Lee, David N. Spergel, Julien Tréguer

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


We present the first detection of a correlation between the Lyman-α forest and cosmic microwave background gravitational lensing. For each Lyman-α forest in SDSS-III/BOSS DR12, we correlate the one-dimensional power spectrum with the cosmic microwave background lensing convergence on the same line of sight from Planck. This measurement constitutes a position-dependent power spectrum, or a squeezed bispectrum, and quantifies the nonlinear response of the Lyman-α forest power spectrum to a large-scale overdensity. The signal is measured at 5σ and is consistent with the expectation of the standard ΛCDM cosmological model. We measure the linear bias of the Lyman-α forest with respect to the dark matter distribution and constrain a combination of nonlinear terms including the nonlinear bias. This new observable provides a consistency check for the Lyman-α forest as a large-scale structure probe and tests our understanding of the relation between intergalactic gas and dark matter. In the future, it could be used to test hydrodynamical simulations and calibrate the relation between the Lyman-α forest and dark matter.

Original languageEnglish (US)
Article number103506
JournalPhysical Review D
Issue number10
StatePublished - 2016

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy (miscellaneous)


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