11:00 am–12:00 pm ERC 401
Hannah Fronenberg (McGill University) "Constraining Cosmology With CMB and LIM Lensing"
Despite concerted effort, we have yet to stitch together a complete and uninterrupted cosmic timeline. Through weak gravitational lensing, the cosmic microwave background (CMB) already has encoded in it information about the history of the matter density field between the surface of last scattering and us, the observer. This information, however, is projected onto a single observable and the high-redshift contribution to this CMB lensing map is dwarfed by that of the low-redshift universe. Luckily, Maniyar et al. 2021 have shown that using a linear combination of lensing maps from both CMB and line intensity mapping (LIM) observations, one can exactly null the low-redshift contribution to CMB lensing, leaving behind the high-redshift matter density field. In this talk, I will discuss the ways in which this new "CMB x LIM-nulling" probe can help us constrain cosmology at high-redshift. Using next-generation instruments we find that the CMB x LIM-nulling convergence serve as a model-independent test of cosmology beyond LambdaCDM and can help constrain various properties of the high-redshift matter power spectrum. I will also discuss how the CMB x LIM-nulling estimator can be used to tomographically measure the baryon acoustic oscillation (BAO) scale across a large portion of cosmic history.
