Poster Presentation

Spectrotomography: Weak Lensing Signal Detection Using Only Spectroscopic Redshifts

Author(s): Lillian Wright (Seoul National University) Jubee Sohn (Seoul National University)

Presenter: Lillian Wright (Seoul National University)

We perform spectroscopic weak lensing tomography for seven massive galaxy clusters at z ∼ 0.1. This is the second reported detection of the cluster weak lensing signal using exclusively spectroscopically confirmed source galaxies, following Dell’Antonio et al. (2020). We utilize high-resolution r2-band imaging from the Subaru Hyper Suprime-Cam and dense spectroscopy from the MMT Hectospec to identify source galaxies and measure shear across source redshift bins. To compare our observations with theory, we model the expected shear as a function of scaled radius for a mock source galaxy sample, assuming an NFW profile and incorporating caustic mass estimates. We detect a significant weak lensing signal (∼3.3σ) for the cluster with the densest spectroscopic sampling, Abell 2255 (M200 ∼ 8.43e14M⊙). To increase source number density and probe the weak lensing signal at smaller radii, we also perform cluster stacking.