Follow-up of SN 2025wny V: Lens Modelling and Cosmography of a Strongly Lensed Superluminous Supernova at z = 2.015 using Space Data

@misc{mortsell2026followup,
  title = {{Follow-up of SN 2025wny V: Lens Modelling and Cosmography of a Strongly Lensed Superluminous Supernova at $z = 2.015$ using Space Data}},
  author = {Edvard Mörtsell and Joel Johansson and Ariel Goobar and Alice Townsend and Hannah C. Turner and Suhail Dhawan and Cameron Lemon and Peter Nugent and Thomas E. Collett and Stephen Thorp and Jacob Osman Hjortlund and Jakob Nordin and Lin Yan and Graham P. Smith and Christoffer Fremling},
  howpublished = {arXiv},
  year = {2026},
  month = aug,
  doi = {10.48550/arxiv.2608.28430},
  eprint = {2608.28430},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2608.28430},
  note = {CC BY 4.0},
}

TY  - UNPB
TI  - Follow-up of SN 2025wny V: Lens Modelling and Cosmography of a Strongly Lensed Superluminous Supernova at z = 2.015 using Space Data
AU  - Edvard Mörtsell
AU  - Joel Johansson
AU  - Ariel Goobar
AU  - Alice Townsend
AU  - Hannah C. Turner
AU  - Suhail Dhawan
AU  - Cameron Lemon
AU  - Peter Nugent
AU  - Thomas E. Collett
AU  - Stephen Thorp
AU  - Jacob Osman Hjortlund
AU  - Jakob Nordin
AU  - Lin Yan
AU  - Graham P. Smith
AU  - Christoffer Fremling
PY  - 2026
DA  - 2026/08/28
PB  - arXiv
DO  - 10.48550/arxiv.2608.28430
UR  - https://arxiv.org/abs/2608.28430
AB  - We present a lensing and cosmographic analysis of the strongly lensed Type I superluminous supernova SN 2025wny at redshift z=2.015, multiply imaged by two foreground galaxies at z=0.376. Using imaging obtained with the Hubble Space Telescope and the James Webb Space Telescope, we model the lens system with two elliptical power-law mass distributions and an external shear component. In addition to the supernova image positions, the modelling incorporates the surface-brightness distribution of the lensed host galaxy. The inferred Einstein radii are θ_E,1≃ 1.6" and θ_E,2≃ 0.7 - $0.8$", with broadly consistent results across all filters. After accounting for microlensing by stars in the lens galaxies, the posterior distribution spans total magnifications of approximately μ_tot∼ 5--$50$, with flux ratios of the multiple images consistent with observations. Combining the lens models with spectroscopically and photomerically measured time delays yields a filter-marginalized constraint of H_0 = 66.7^+7.6_−6.3 km s^−1 Mpc^−1, for a fiducial model with isothermal mass profiles. Allowing the density slopes of the lens galaxies to vary over a broad range results in H_0 = 70.8^+8.2_−6.1 km s^−1 Mpc^−1. These values are conditional on the adopted parameterization of the lens mass distribution, the assumed priors on the density slopes, and possible additional lensing contributions from the surrounding large-scale environment. We find that incorporating the currently available stellar kinematic measurements has only a modest effect on the inferred value of H_0. Future measurements of the lens-galaxy kinematics and a detailed characterization of the lens environment will further strengthen the utility of SN 2025wny as a cosmological probe.
ER  -