Kinematic Lensing Ratio: Reviving Weak Lensing Cosmography as a Geometric Dark Energy Probe
Published in arXiv e-prints, 2026
Qinxun Li "Kinematic Lensing Ratio: Reviving Weak Lensing Cosmography as a Geometric Dark Energy Probe." arXiv e-prints, 2026.
Abstract
We introduce the kinematic lensing ratio (KiLeR), a geometric dark-energy probe from weak lensing. Combining shear ratios with intrinsic galaxy shapes inferred from kinematics, KiLeR naturally mitigates most first-order lensing systematics, including redshift errors, intrinsic alignments, and baryonic effects. The forecast on Roman shows a 192% improvement in the state-of-the-art dark energy constraints from adding KiLeR, providing independent tests of the evolving dark energy hint in the DESI DR2 BAO+CMB+SN analysis. We quantify the science requirements on systematic and statistical error control and discuss the pathways towards KiLeR observation.