Neutrinos are the only known form of dark matter, comprising between half and a few percent of the total dark mass in the Universe. Due to thermal motion, neutrino clustering is suppressed on scales below the free-streaming length, which strongly affects the formation of cosmic structure. As a result, galaxy clustering diagnostics are sensitive to the cosmic neutrino content, providing by far the most stringent constraints on the sum of neutrino masses, a key Standard Model parameter that has yet to be measured. At the same time, clustering is also affected by astrophysical processes, such as feedback from active galactic nuclei. To make progress in disentangling these effects, we recently carried out the largest hydrodynamical neutrino simulations to date, using a new sub-grid physics model called FLAMINGO (Schaye et al., 2023) and a sophisticated treatment of massive neutrinos (see below).

Use the slider to view the same large-scale perturbations in the density of stars, neutrinos, cold dark matter, and gas.

Fig. 1 Mass densities of stars, neutrinos, CDM, and gas in a slice of the baseline 1 Gpc FLAMINGO simulation. You can move the slider in the middle to compare the different components.

FLAMINGO papers (galaxy formation model, calibration)

Joop Schaye, Roi Kugel, Matthieu Schaller, John C. Helly, Joey Braspenning, Willem Elbers et al. (2023), The FLAMINGO project: cosmological hydrodynamical simulations for large-scale structure and galaxy cluster surveys, Monthly Notices of the Royal Astronomical Society, 526 (4), 4978-5020. Available at https://doi.org/10.1093/mnras/stad2419.

Roi Kugel, Joop Schaye, Matthieu Schaller, John C. Helly, Joey Braspenning, Willem Elbers et al. (2023), FLAMINGO: Calibrating large cosmological hydrodynamical simulations with machine learning, Monthly Notices of the Royal Astronomical Society, 526 (4), 6103-6127. Available at https://doi.org/10.1093/mnras/stad2540.

Main neutrino reference (non-linear treatment of neutrinos)

Willem Elbers, Carlos S. Frenk, Adrian Jenkins, Baojiu Li, and Silvia Pascoli (2021), An optimal nonlinear method for simulating relic neutrinos, Monthly Notices of the Royal Astronomical Society, 507 (2), 2614-2631. Available at https://doi.org/10.1093/mnras/stab2260.

Higher-order initial conditions with neutrinos

Willem Elbers, Carlos S. Frenk, Adrian Jenkins, Baojiu Li, and Silvia Pascoli (2022), Higher order initial conditions with massive neutrinos, Monthly Notices of the Royal Astronomical Society, 516 (3), 3821–3836. Available at https://doi.org/10.1093/mnras/stac2365.

Treatment of neutrinos at high redshift & relativistic equations of motion

Willem Elbers (2022), Geodesic motion and phase-space evolution of massive neutrinos, arXiv:2207.14256. Available at http://arxiv.org/abs/2207.14256.