2025/04/01 by Nandini Sahu, Anowar J. Shajib, Sahu, Nandini +31 · 2 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics of Galaxies (astro-ph.GA) #Cosmology and Gravitation Theories #Cosmology and Nongalactic Astrophysics (astro-ph.CO) #FOS: Physical sciences #Galaxies: Formation, Evolution, Phenomena
paper · pdf · doi:10.48550/arxiv.2504.00656
openalex publication_date 2025/04/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Strong gravitational lenses with two background sources at widely separated redshifts are a powerful and independent probe of cosmological parameters. We can use these systems, known as Double-Source-Plane Lenses (DSPLs), to measure the ratio (β) of angular-diameter distances of the sources, which is sensitive to the matter density (Ωm) and the equation-of-state parameter for dark-energy (w). However, DSPLs are rare and require high-resolution imaging and spectroscopy for detection, lens modeling, and measuring β. Here we report only the second DSPL ever used to measure cosmological parameters. We model the DSPL AGEL150745+052256 from the ASTRO 3D Galaxy Evolution with Lenses (AGEL) survey using HST/WFC3 imaging and Keck/KCWI spectroscopy. The spectroscopic redshifts for the deflector and two sources in AGEL1507 are z\rm defl=0.594, z\rm S1=2.163, and z\rm S2=2.591. We measure a stellar velocity dispersion of σ\rm obs=109 ± 27 km s-1 for the nearer source. Using σ\rm obs for the main deflector (from literature) and S1, we test the robustness of our DSPL model. We measure β=0.953+0.008-0.010 for AGEL1507 and infer Ω\rm m=0.33+0.38-0.23 for ΛCDM cosmology. Combining AGEL1507 with the published model of the Jackpot lens improves the precision on Ω\rm m (ΛCDM) and w (wCDM) by ∼ 10 %. The inclusion of DSPLs significantly improves the constraints when combined with Plancks cosmic microwave background observations, enhancing precision on w by 30 %. This paper demonstrates the constraining power of DSPLs and their complementarity to other standard cosmological probes. Tighter future constraints from larger DSPL samples discovered from ongoing and forthcoming large-area sky surveys would provide insights into the nature of dark energy.