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arXiv · 2604.26015

Kinematic Lensing Ratio: Reviving Weak Lensing Cosmography as a Geometric Dark Energy Probe

Qinxun Li
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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.

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Qinxun Li. 2026-04-28. Kinematic Lensing Ratio: Reviving Weak Lensing Cosmography as a Geometric Dark Energy Probe. https://arxiv.org/abs/2604.26015

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