Cold Dark Matter and Self-interacting Dark Matter Interpretations of the Strong Gravitational Lensing Object JWST-ER1

Abstract

van Dokkum et al. reported the discovery of JWST-ER1, a strong lensing object at redshift z ≈ 2, using data from the James Webb Space Telescope. The lens mass within the Einstein ring is 5.9 times higher than the expected stellar mass from a Chabrier initial mass function, indicating a high dark matter density. In this work, we show that a cold dark matter halo, influenced by gas-driven adiabatic contraction, can account for the observed lens mass. We interpret the measurement of JWST-ER1 in the self-interacting dark matter scenario and show that the cross section per particle mass σ/m ≈ 0.1 cm2 g−1 is generally favored. Intriguingly, σ/m ≈ 0.1 cm2 g−1 can also be consistent with the strong lensing observations of early-type galaxies at redshift z ≈ 0.2, where adiabatic contraction is not observed overall.

Self-interacting Dark Matter Interpretation of Crater II

“…There are stringent constraints on the cross section on the scales of galaxy clusters σ/m  0.1 cm 2 g −1 for Ṽmax -1500 km s 1 (Peter et al 2013;Rocha et al 2013;Harvey et al 2015;Kaplinghat et al 2016;Sagunski et al 2021;Andrade et al 2022) and elliptical galaxies (Kong 2024). Thus, a viable SIDM model must have a velocity-dependent cross section, which is strong in dwarf galaxies, while diminishing toward the clusters; see Tulin & Yu (2018) and references therein for the discussion about particle physics realizations of SIDM.…”