Time-delay cosmographic forecasts with strong lensing and JWST stellar kinematics

Understand

We present a joint strong lensing and stellar dynamical framework for future time-delay cosmography purposes.

• Based on a pixelated source reconstruction and the axisymmetric Jeans equations, we are capable of constraining cosmological distances and hence the current expansion rate of the Universe ($H_0$) to the few percent level per lens, when high signal-to-noise integral field unit (IFU) observations from the next generation of telescopes become available.
• For illustrating the power of this method, we mock up IFU stellar kinematic data of the prominent lens system RXJ1131-1231, given the specifications of the James Webb Space Telescope.
• Our analysis shows that the time-delay distance ($D_{\Delta t}$) can be constrained with 3.1% uncertainty at best, if future IFU stellar kinematics are included in the fit and if the set of candidate model parameterisations contains the true lens potential.