Project Leda

Highlights

Probing the dark matter distribution on scales of a few hundred parsecs requires a high angular resolution of a few milli-arcseconds. Currently, this is only provided by interferometric arrays at cm and mm-wavelengths. In order to analyse this type of data, this ERC-funded group has developed a new lens modelling code that fits the data directly in the visibility space. By applying our technique to milli-arcsecond angular-resolution data taken with the Global Very Long Baseline Interferometer network we have set competitive limits on Fuzzy dark matter. We have gravitationally imaged what is currently the lowest-mass dark-matter halo to have been gravitationally detected so far and shown that its properties are in strong tension with CDM. At the same time, we have developed a lens modelling code that allows us to simultaneously and self-consistently constrain the polarised properties of the lensed source, the mass distribution of the lens and the magnetic-ionic properties of its ISM.

Members

Simona Vegetti
Simon Ndiritu
Devon Powell
Hannah Stacey

Publications

A self-consistent framework to study magnetic fields with strong gravitational lensing and polarised radio sources.
Ndiritu et al. (2024), MNRAS, 538, 671

Complex angular structure of three elliptical galaxies from high-resolution ALMA observations of strong gravitational lenses.
Stacey et al. (2024), A&A, 688, A110

Strong gravitational lensing as a probe of dark matter.
Vegetti et al. (2024), Space Science Reviews, 220, 58

A lensed radio jet at milli-arcsecond resolution - II. Constraints on fuzzy dark matter from an extended gravitational arc.
Powell et. al (2023), MNRAS, 524, 84

A lensed radio jet at milliarcsecond resolution I: Bayesian comparison of parametric lens models.
Powell et. al (2022), MNRAS, 516, 1808

A novel approach to visibility-space modelling of interferometric gravitational lens observations at high angular resolution.
Powell et. al (2021), MNRAS, 501, 515

The rocky road to quiescence: compaction and quenching of quasar host galaxies at z ∼ 2.
Stacey et. al (2020), MNRAS, 500, 3667