Quantifying the Line-of-Sight Halo Contribution to the Dark Matter Convergence Power Spectrum from Strong Gravitational Lenses

Understand

Galaxy-galaxy strong gravitational lenses have become a popular probe of dark matter (DM) by providing a window into structure formation on the smallest scales.

• In particular, the convergence power spectrum of subhalos within lensing galaxies has been suggested as a promising observable to study DM.
• However, the distances involved in strong-lensing systems are vast, and we expect the relevant volume to contain line-of-sight (LOS) halos that are not associated with the main lens.
• We develop a formalism to calculate the effect of LOS halos as an effective convergence power spectrum.