FDM Structure Formation

H.-Y. Schive, T. Chiueh, and T. Broadhurst, Nature Physics, 2014

Quantifying Mixed Fuzzy and Cold Dark Matter Halo Dynamics

• Radial density profiles
• CDM velocity dispersion vs. FDM granular structure
• Solitonic core dynamics

using

• AMR grid structure
• Finite differencing
• Spectral codes
• N-body algorithms

AxioNyx: Simulating Mixed Fuzzy and Cold Dark Matter

Goal:

• AMR simulations for Mixed Dark Matter
• CDM -> N-body scheme
• FDM -> Spectral/Finite-difference method
• Baryonic physics -> Nyx modules for hydrodynamics and feedback

BS,  MS, Christoph Behrens, Jens C. Niemeyer, and Richard Easther, arXiv:2007.08256

Spherical Collapse - linear

Spherical Collapse - Non-linear

Spherical Collapse - Non-linear

Conclusions

• Distinguishing features of FDM: Strong stochastic density fluctuations in halos on deBroglie length and time scales and formation of stable, oscillating soliton cores in center of  halos
  • Local FDM density important for experiments but not well constraint yet
  • Heavier FDM mass can be best constrained on non-linear, galactic scales (soliton osc., soliton mergers, gravitational heating/cooling, tidal disruption,...)

-- Need further dedicated FDM simulations on galactic scales --

• FDM structure formation similar to CDM on super deBroglie scales (except cut-off in initial power spectrum as for WDM)
  • Weakly non-linear probes like Lyman-alpha exclude