JWST Lensed quasar dark matter survey II: Strongest gravitational lensing limit on the dark matter free streaming length to date

Understand

This is the second in a series of papers in which we use JWST MIRI multiband imaging to measure the warm dust emission in a sample of 31 multiply imaged quasars, to be used as a probe of the particle nature of dark matter.

• We present measurements of the relative magnifications of the strongly lensed warm dust emission in a sample of 9 systems.
• The warm dust region is compact and sensitive to perturbations by populations of halos down to masses $\sim 10^6$ M$_{\odot}$.
• Using these warm dust flux-ratio measurements in combination with 5 previous narrow-line flux-ratio measurements, we constrain the halo mass function.