Gravitational lensing of line intensity maps

Dec 03, 2018 - 11:00 am to 12:00 pm

Campus, Varian 355

Simon Foreman (CITA, Toronto)

Gravitational lensing of the cosmic microwave background (CMB) has emerged as a powerful cosmological probe, made possible by the development and characterization of nearly-optimal estimators for extracting the lensing signal from temperature and polarization maps. One can ask whether similar tools can be applied to upcoming "intensity maps" of emission lines at various wavelengths (e.g. 21cm). Following an introduction to the essential concepts of CMB lensing, I will present recent work in this direction, focusing on the impact of nonlinear gravitational clustering on standard CMB lensing estimators when applied to intensity maps. I will show how these nonlinearities can provide a significant contaminant to lensing reconstruction, but will also describe how this contamination can largely be mitigated by modifying the lensing estimator. Finally, I will present estimates for the detectability of lensing in ongoing and future intensity mapping surveys, and highlight related work on reconstructing large-angle information in galaxy surveys and CMB maps.