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arXiv · 2511.00788

A cosmographic analysis using DESI-DR2 and strong lensing: I. Time-Delay measurements

Darshan Kumar·Deepak Jain·Shobhit Mahajan
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Abstract

Strong gravitational lensing time-delay measurements, together with the distance sum rule (DSR), offer a model-independent approach to probe the geometry and expansion of the universe without relying on a fiducial cosmological model. In this work, we perform a cosmographic analysis by combining the latest Type Ia supernova datasets (PantheonPlus, DESY5, and Union3), baryon acoustic oscillation data from DESI-DR2, and updated time-delay distances from strong lensing systems. The analyses using SGL with individual SNIa datasets (SGL+PantheonPlus, SGL+DESY5, and SGL+Union3) indicate a preference for an open universe, though they remain consistent with spatially flat universe at the $95%$ confidence level. When DESI-DR2 data is included in each combination, the constraints tighten and shift slightly toward a closed universe, while flatness remains supported at the $68%$ confidence level. The best-fit values of $q_0$ and $j_0$ agree with $\Lambda$CDM expectations within $95%$ or $99%$ confidence depending on the dataset, whereas $s_0$ remains weakly constrained in all cases. This work is the first in a series of two companion papers on cosmography with DESI-DR2 and strong lensing.

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Darshan Kumar, Deepak Jain, Shobhit Mahajan. 2025-11-02. A cosmographic analysis using DESI-DR2 and strong lensing: I. Time-Delay measurements. https://arxiv.org/abs/2511.00788

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