Dartmouth Events

Abstract: Gravitational lensing of the cosmic microwave background has emerged as a powerful cosmological probe, made possible by the development and detailed 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 other wavelengths (e.g. 21cm). In this talk, I will present ongoing work in this direction, focusing in particular on the impact of gravitational nonlinearities on traditional quadratic lensing estimators. I will show how these nonlinearities can provide a significant contaminant to lensing reconstruction, even for observations at reionization-era redshifts, but will also describe how this contamination can largely be mitigated by modifying the lensing estimator. I will also present estimates for the detectability of lensing in ongoing and future intensity mapping surveys.