Dark Matter Group 2015 - 2020

Highlights

Using optical data, this MPRG group (2015–2020) searched for the presence of low-mass dark matter haloes and found the results to be consistent with the predictions of cold dark matter. For the first time, we combined constraints from strong gravitational lensing with those from Milky Way satellite galaxies and the Lyman-α forest, enabling a unified test of dark matter models across a wide range of scales. This joint analysis allowed us to rule out the 7.1 keV sterile neutrino dark matter scenario, as well as specific models of self-interacting dark matter. We further demonstrated that low-mass haloes along the line of sight (field haloes) make a significant contribution to the population of detectable perturbers, and that the angular resolution of the data is a key factor in determining sensitivity to these objects. In parallel, we developed a three-dimensional Bayesian gravitational-lens modelling code to study the kinematic properties of lensed high-redshift galaxies. By combining this novel framework with high-angular-resolution observations from ALMA, we identified, for the first time, dynamically cold, rotating disc galaxies at redshifts four and five.

Members

Simona Vegetti
Giulia Despali
Wolfgang Enzi
Elisa Ritondale
Francesca Rizzo

Publications

Dynamical properties of z~4.5 dusty star-forming galaxies and their connection with local early-type galaxies. Rizzo et al. (2021), MNRAS, 507, 3952

Joint constraints on thermal relic dark matter from strong gravitational lensing, the Ly α forest, and Milky Way satellites. Enzi et al. (2021), MNRAS, 506, 5848

A dynamically cold disk galaxy in the early Universe. Rizzo et al. (2020), Nature, 584, 201

Systematic errors in strong gravitational lensing reconstructions, a numerical simulation perspective. Enzi et al. (2020), MNRAS, 496, 1718

The lensing properties of subhaloes in massive elliptical galaxies in sterile neutrino cosmologies. Despali et al. (2020), MNRAS, 491, 1295

Low-mass halo perturbations in strong gravitational lenses at redshift z ∼ 0.5 are consistent with CDM. Ritondale et al. (2019), MNRAS, 485, 2179

The interplay of self-interacting dark matter and baryons in shaping the halo evolution. Despali et al. (2019), MNRAS, 484, 4563

Resolving on 100 pc scales the UV-continuum in Lyman-α emitters between redshift 2 and 3 with gravitational lensing. Ritondale et al. (2019), MNRAS, 482, 4744

A novel 3D technique to study the kinematics of lensed galaxies. Rizzo et al. (2018), MNRAS, 481, 5606

Constraining sterile neutrino cosmologies with strong gravitational lensing observations at redshift z ∼ 0.2. Vegetti et al. (2018), MNRAS, 481, 3661

Modelling the line-of-sight contribution in substructure lensing. Despali et al. (2018), MNRAS, 475, 5424

The impact of baryonic physics on the subhalo mass function and implications for gravitational lensing. Despali et al. (2017), MNRAS, 469, 1997