Testing the Cosmological Model with Weak Lensing


Alexandra Amon


Apr 29, 2024






Weak gravitational lensing provides an immense opportunity to test the standard LCDM cosmology in the non-linear regime. Over the last decade, it has matured as a high-precision tool with on-going surveys like the Dark Energy Survey (DES), which has imaged 5000 square degrees and 100 million galaxies. Intriguingly, weak-lensing surveys have consistently reported a mild cosmological tension:  low values of the clustering amplitude parameter (S_8) compared to that predicted by observations of the Cosmic Microwave Background. Is this a hint of a tension between the early and late Universe, as typically presented, or between linear and non-linear scales?  On the eve of Rubin Observatory's Legacy Survey of Space and Time (LSST), which will measure weak lensing with billions of galaxies, I will present new approaches to exploit these data and test the scale-dependence of the cosmological model.


Alexandra Amon is an Assistant Professor in Astrophysics at Princeton University. Her research focuses on cosmology and understanding our dark Universe, mostly using 'weak gravitational lensing'. She co-leads the weak lensing team in the Dark Energy Survey (DES). She has previously held postdoctoral fellowships at Cambridge University and Stanford University, and obtained her PhD from the University of Edinburgh. She has won both the Royal Astronomical Society's Pension Thesis Award (2018) and the Winton Early Career Award (2023). She was elected a 2020 Rising Star in Physics. Amon is passionate about science outreach and an advocate for making STEM fields more accessible and welcoming to everyone.

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