PIRSA:25120028

Cosmology and astrophysics from the combination of CMB and galaxy lensing

Ouellette, A. (2025). Cosmology and astrophysics from the combination of CMB and galaxy lensing. Perimeter Institute. https://pirsa.org/25120028

Ouellette, Aaron. Cosmology and astrophysics from the combination of CMB and galaxy lensing. Perimeter Institute, Dec. 11, 2025, https://pirsa.org/25120028 

          @misc{ pirsa_PIRSA:25120028,
            doi = {10.48660/25120028},
            url = {https://pirsa.org/25120028},
            author = {Ouellette, Aaron},
            keywords = {Cosmology},
            language = {en},
            title = {Cosmology and astrophysics from the combination of CMB and galaxy lensing},
            publisher = {Perimeter Institute},
            year = {2025},
            month = {dec},
            note = {PIRSA:25120028 see, \url{https://pirsa.org}}
          }

Aaron Ouellette University of Illinois

Talk numberPIRSA:25120028
DOI10.48660/25120028
Collection
Talk Type Scientific Series
Subject

Abstract

Weak lensing of galaxies and of the CMB provide direct probes of the cosmic matter density field, but are sensitive to different redshift ranges and different survey systematics. The combination of these probes provides a way to calibrate systematics and test LCDM across cosmic time. I will talk about the cross-correlation of cosmic shear and CMB lensing using DES Y3 and new lensing reconstructions from SPT-3G. The main result of this analysis is a first high-significance measurement of the lensing-shear cross-correlation using polarization-only lensing maps, allowing us to sidestep the issue of extragalactic foregrounds without losing much constraining power on large scales. Additionally, using a pure blue shear sample and a variety of foreground-mitigated CMB lensing reconstructions we are able to conduct data-driven tests to ensure our results are robust to both galaxy intrinsic alignments and foregrounds in the CMB.