The benefits of CMB delensing

Selim C. Hotinli, Joel Meyers, Cynthia Trendafilova, Daniel Green, Alexander Van Engelen

Research output: Contribution to journalArticlepeer-review

Abstract

The effects of gravitational lensing of the cosmic microwave background (CMB) have been measured at high significance with existing data and will be measured even more precisely in future surveys. Reversing the effects of lensing on the observed CMB temperature and polarization maps provides a variety of benefits. Delensed CMB spectra have sharper acoustic peaks and more prominent damping tails, allowing for improved inferences of cosmological parameters that impact those features. Delensing reduces B-mode power, aiding the search for primordial gravitational waves and allowing for lower variance reconstruction of lensing and other sources of secondary CMB anisotropies. Lensing-induced power spectrum covariances are reduced by delensing, simplifying analyses and improving constraints on primordial non-Gaussianities. Biases that result from incorrectly modeling nonlinear and baryonic feedback effects on the lensing power spectrum are mitigated by delensing. All of these benefits are possible without any changes to experimental or survey design. We develop a self-consistent, iterative, all-orders treatment of CMB delensing on the curved sky and demonstrate the impact that delensing will have with future surveys.

Original languageEnglish (US)
Article number020
JournalJournal of Cosmology and Astroparticle Physics
Volume2022
Issue number4
DOIs
StatePublished - Apr 1 2022
Externally publishedYes

Keywords

  • CMBR polarisation
  • cosmological parameters from CMBR
  • gravitational waves and CMBR polarization
  • weak gravitational lensing

ASJC Scopus subject areas

  • Astronomy and Astrophysics

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