Extending Cluster Lensing Mass Inversion (?-CLUMI+): Combining Dynamics and Lensing for Accurate Galaxy Cluster Mass Reconstruction in the Infall Region
Michele Pizzardo (Academia Sinica, Taiwan)
Tuesday 23/06/2026 @ 14:00, Sala Antonio Sollima (IV piano Battiferro)
Accurate reconstruction of galaxy cluster mass profiles beyond the virial radius is vital for testing non-equilibrium halo assembly, dark matter physics, and modified gravity. In this talk, we present ?-CLUMI+, a minimally model-dependent, data-driven, multi-probe framework that reconstructs the mass distribution in and around galaxy clusters by combining weak lensing (shear and magnification) and dynamical (escape velocity) observations. ?-CLUMI+ is an extension of the original CLUMI+ methodology, which models escape velocity within a standard Newtonian framework. ?-CLUMI+ now incorporates the effects of accelerated cosmic expansion into the modeling of the escape velocity profile. Using a statistical sample of synthetic lensing and phase-space observations from the IllustrisTNG-300 simulation, we show that both approaches yield unbiased mass profile reconstructions up to ?10 Mpc. Crucially, accounting for cosmic acceleration mitigates systematic modeling errors and improves the accuracy of the reconstruction within the cluster infall region. Furthermore, we demonstrate that the ?-CLUMI+ methodology provides robust mass reconstructions even in the absence of magnification data, establishing a powerful baseline for cosmological applications in the era of wide-field imaging and spectroscopic surveys such as DESI, Euclid, and the Nancy Grace Roman Space Telescope.