H0LiCOW VIII. A weak lensing measurement of the external convergence in the field of the lensed quasar HE$\,$0435$-$1223

Understand

We present a weak gravitational lensing measurement of the external convergence along the line of sight to the quadruply lensed quasar HE$\,$0435$-$1223.

• Using deep r-band images from Subaru-Suprime-Cam we observe galaxies down to a 3$\sigma$ limiting magnitude of $\sim 26$ mags resulting in a source galaxy density of 14 galaxies / arcmin$^2$ after redshift-based cuts.
• Using an inpainting technique and Multi-Scale Entropy filtering algorithm, we find that the region in close proximity to the lens has an estimated external convergence of $\kappa=-0.012^{+0.020}_{-0.013}$ and is hence marginally under-dense.
• We also rule out the presence of any halo with a mass greater than $M_{\rm vir}=1.6\times10^{14}h^{-1}M_\odot$ (68$\%$ confidence limit).