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arXiv · 2509.15012

Constraining Cosmology with Double-source-plane Strong Gravitational Lenses from the AGEL Survey

Abstract

Double-source-plane strong gravitational lenses (DSPLs), with two sources at different redshifts, are independent cosmological probes of the dark energy equation of state parameter $w$ and the matter density parameter $Ω_{\rm m}$. We present the lens model for the DSPL AGEL035346$-$170639 and infer cosmological constraints from this system for flat $Λ$ cold dark matter and flat $w$CDM cosmologies. From the joint posterior of $w$ and $Ω_{\rm m}$ in the flat $w$CDM cosmology, we extract the following median values and 1$σ$ uncertainties: $w = -1.52^{+0.49}_{-0.33}$ and $Ω_{\rm m} = 0.192^{+0.305}_{-0.131}$ from AGEL0353 alone. Combining our measurements with two previously analyzed DSPLs, we present the joint constraint on these parameters from a sample of three, the largest galaxy-scale DSPL sample used for cosmological measurement to date. The combined precision of $w$ from three DSPLs is higher by 15% over AGEL0353 alone. Combining DSPL and cosmic microwave background (CMB) measurements improves the precision of $w$ from CMB-only constraints by 39%, demonstrating the complementarity of DSPLs with the CMB. Despite their promising constraining power, DSPLs are limited by sample size, with only a handful discovered so far. Although ongoing and near-future wide-area sky surveys will increase the number of known DSPLs by up to two orders of magnitude, these systems will still require dedicated high-resolution imaging and spectroscopic follow-ups like those presented in this paper. Our ASTRO 3D Galaxy Evolution with Lenses collaboration is undertaking such follow-up campaigns for several newly discovered DSPLs and will provide cosmological measurements from larger samples of DSPLs in the future.

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BibTeXRIS

Duncan J. Bowden, Nandini Sahu, Anowar J. Shajib, Kim-Vy Tran, Tania M. Barone, Keerthi Vasan G. C., Daniel J. Ballard, Thomas E. Collett, Faith Dalessandro, Giovanni Ferrami, Karl Glazebrook, William J. Gottemoller, Leena Iwamoto, Tucker Jones, Glenn G. Kacprzak, Geraint F. Lewis, Haven McIntosh-Lombardo, Hannah Skobe, Sherry H. Suyu, Sarah M. Sweet. 2025-11-04. Constraining Cosmology with Double-source-plane Strong Gravitational Lenses from the AGEL Survey. https://doi.org/10.3847/1538-4357%2Fae092e

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