Delensing Degree-Scale $B$-Mode Polarization with High-Redshift Line Intensity Mapping

Abstract

Cosmic microwave background (CMB) experiments that constrain the tensor-to-scalar ratio $r$ are now approaching the sensitivity at which delensing---removing the $B$ modes induced by the gravitational lensing of large-scale structure---is necessary. We consider the improvement in delensing that maps of large-scale structure from tomographic line intensity mapping (IM) experiments targeting $2<z<10$ could provide. Compared to a nominal baseline of cosmic infrared background and internal delensing at CMB-S4 sensitivity, we find that the addition of high-redshift IM data could improve delensing performance by ~11%. Achieving the requisite sensitivity in the IM data is feasible with next-generation experiments that are now being planned. However, these results are contingent on the ability to measure low-$k$ modes along the line of sight. Without these modes, IM datasets are unable to to correlate with the lensing kernel and do not aid in delensing.

9 pages, 4 figures, 1 table. Matches version published in Phys. Rev. D

References in corpus (11)

• Measurement of 21 cm brightness fluctuations at z ~ 0.8 in cross-correlation
• Canadian Hydrogen Intensity Mapping Experiment (CHIME) Pathfinder
• The Epoch of Reionization Window: II. Statistical Methods for Foreground Wedge Reduction
• HIRAX: A Probe of Dark Energy and Radio Transients
• First Season MWA EoR Power Spectrum Results at Redshift 7
• Carbon monoxide line emission as a CMB foreground: tomography of the star-forming universe with different spectral resolutions
• Demonstration of cosmic microwave background delensing using the cosmic infrared background
• Dissecting the high-z interstellar medium through intensity mapping cross-correlations
• Cosmic 21-cm Delensing of Microwave Background Polarization and the Minimum Detectable Energy Scale of Inflation
• MKID development for SuperSpec: an on-chip, mm-wave, filter-bank spectrometer
• Intensity Mapping in the Presence of Foregrounds and Correlated Continuum Emission

Cited by in corpus (11)

• Line-Intensity Mapping: Theory Review
• The Simons Observatory: Constraining inflationary gravitational waves with multi-tracer B-mode delensing
• Limitations of CMB B-mode template delensing
• Comparison of delensing methodologies and assessment of the delensing capabilities of future experiments
• LiteBIRD Science Goals and Forecasts: Improving Sensitivity to Inflationary Gravitational Waves with Multitracer Delensing
• The impact of extragalactic foregrounds on internal delensing of CMB B-mode polarization
• A numerical study of observational systematic errors in lensing analysis of CMB polarization
• A multi-tracer empirically-driven approach to line-intensity mapping lightcones
• Large Scale Structure Reconstruction with Short-Wavelength Modes
• Delensing of Cosmic Microwave Background Polarization with machine learning
• Characterization of Extragalactic Point-Sources on E- and B-mode Maps of the CMB Polarization