Can we use Weak Lensing to Measure Total Mass Profiles of Galaxies on 20 kiloparsec Scales?

Understand

Current constraints on dark matter density profiles from weak lensing are typically limited to radial scales greater than 50-100 kpc.

• In this paper, we explore the possibility of probing the very inner regions of galaxy/halo density profiles by measuring stacked weak lensing on scales of only a few tens of kpc.
• Our forecasts focus on scales smaller than the equality radius (Req) where the stellar component and the dark matter component contribute equally to the lensing signal.
• We compute the evolution of Req as a function of lens stellar mass and redshift and show that Req=7-34 kpc for galaxies with the stellar mass of 10^{9.5}-10^{11.5} solar masses.