Year: 2025
Type: preprint
Abstract: We investigate late-time cosmology using a compiled sample of ≈ 85 galaxy-scale strong gravitational lenses, exploiting the fact that lensing directly probes geometry through the distance ratio D ls /D s while remaining effectively independent of the Hubble constant H 0 .For each system we infer D ls /D s from the observed Einstein radius and stellar velocity dispersion under a standard, spherically symmetric mass description of the lens galaxy.We then confront these measurements with the predictions of two dark-energy scenarios in a spatially flat universe: ΛCDM (cosmological constant) and wCDM with a constant, yet free, equationof-state parameter w.The theoretical distance ratios are computed from the expansion history E(z) and line-of-sight integrals between the lens and source redshifts.Parameter estimation proceeds via a straightforward χ 2 minimization built from per-lens uncertainties, yielding (i) profiled one-dimensional likelihood curves for Ω m0 and w, and (ii) joint confidence contours in the (Ω m0 , w) plane.The resulting constraints demonstrate that strong lensing alone provides precise, H 0 -independent information on the matter density and dark-energy phenomenology.In ΛCDM, the best-fit matter density and its confidence interval are obtained from the profiled χ 2 curve; in wCDM, the twoparameter contours capture the expected degeneracy between Ω m0 and w while still delivering competitive bounds on each.Overall, our analysis shows that a uniform treatment of galaxy-scale lenses-linking well-measured imaging and stellar kinematics to distance-ratio predictions-offers a clean and efficient route to cosmological constraints.The framework is simple, reproducible, and readily extensible: it can incorporate alternative lens models, larger samples, or be combined with complementary probes (e.g., supernovae, BAO, CMB) to further sharpen constraints and test the robustness of the late-time expansion.
DOI: 10.58445/rars.3130
Authors: Yashvardhan Marda, Dron Paul Choudhury
Institution: University of California, Los Angeles
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
OpenAlex ID: W4414580811
Cites:
Cited by:
Related to: