From the analysis of optical data, this MPRG group (2015-2020) has searched for the presence of low-mass dark matter haloes and found it to be consistent with cold dark matter predictions. For the first time, we have combined constraints on dark matter from strong gravitational lensing, the Milky-Way satellite galaxies and the Lyman-alpha Forest. This has allowed us to rule out the 7.1 keV sterile neutrino dark matter model, as well as specific models of self-interacting dark matter. We have also shown how low-mass haloes located along the line-of-sight (field haloes) represent an important contribution to the total number of detectable objects and how the angular resolution of the data plays a key role in setting the data sensitivity to the presence of these objects. At the same time, we have developed a 3D Bayesian gravitational lens modelling code to study the kinematic properties of lensed high-redshift galaxies. By combining the power of this novel technique with high-angular resolution observations from ALMA, we have identified, for the first time, the existence of dynamically cold rotating disc galaxies at redshift four and five.


Simona Vegetti
Giulia Despali
Wolfgang Enzi
Elisa Ritondale
Francesca Rizzo


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.
Despli 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