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Résumé : Galaxy clusters are the largest gravitationally bound objects in the Universe and provide crucial insight to the standard model of Cosmology. Their abundance as a function of mass and redshift is highly sensitive to cosmological parameters such as the amplitude of matter fluctuations and the dark energy equation of state.

Though galaxy clusters are powerful probes of cosmology, they are currently limited by a ~15% mass uncertainty. Future optical (LSST) and X-ray (eROSITA) surveys will provide even larger samples of galaxy clusters; our ability to fully realise the potential of these samples depends on better mass estimates. Gravitational lensing is widely considered as the gold standard in mass estimation.

In this talk I will present a method to extract the lensing signal from the Cosmic Microwave Background (CMB) data. With this method we predict mass uncertainties will be improved to 3-6% for upcoming CMB experiments (SPT-3G, AdvACT etc) to less than 1% for next stage CMB experiment (CMB-S4).

Measuring the mass of galaxy clusters with cosmic microwave background lensing

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