Alvaro tells us about a recent paper where he an collaborators detect the transition between a core (flat density profile) and halo (power law density profile) in dwarf galaxies.
The full core + halo profile matches very closely what is expected in wave/ultralight/fuzzy/axionic dark matter simulations (without baryonic effects included). That is, there is a very flat core, which then drops off suddenly and then flattens off to a decaying power-law profile. The core matches the soliton expected in wave dark matter and the halo matches an outer NFW profile expected outside the soliton.
They also detect evidence for tidal stripping of the matter in the galaxies. The galaxies closer to the centre of the milky way have their transition point between core and halo happen at smaller densities (despite the core density itself not being systematically smaller). The transition also appears to happen closer to the centre of the galaxy, which matches simulations.
Of course the core-+halo pattern they have clearly observed might be due to something else, but the match between wave dark matter simulations and observations is impressive.
The huge caveat is that the mass for the dark matter that they use is very small and in significant tension with Lyman Alpha constraints for wave-like dark matter. This might indicate that the source of this universal core+halo pattern they’re observing comes from something else, or it might indicate that the wave dark matter is more complicated than vanilla models…
Stay tuned to the arXiv for future papers looking at this in more detail!
Cosmology Talks 