Unified Halo Mass Function Spans 21 Orders of Magnitude from Planetary to Cluster Scales in ΛCDM
Zheng et al. combine VVV and large-box ΛCDM simulations to produce a single halo mass function fit valid from planetary to cluster masses and z=30 to 0. The subsampling method recovers unbiased abundances from void regions with 2-3% accuracy at low redshift. This bridges previously disconnected scales and supplies a practical tool for cosmology and structure-formation calculations.
The work combines the high-resolution VVV void-in-void simulations with lower-resolution large-volume runs and introduces a subsampling technique to recover the global mass function from biased underdense regions. This approach directly addresses the dynamic-range problem that has fragmented prior studies into separate planetary, galactic, and cluster regimes. The resulting analytic fit, extending Reed et al., reproduces the simulated abundance to within 2-3% at z<2 and 7% at z>5 while remaining robust under modest cosmological parameter shifts.
Previous narrow-scale simulations missed the continuous power-law behavior that emerges when the thermal cutoff at 100 GeV CDM particle mass is connected to cluster-scale collapse. The new coverage reveals that the low-mass slope remains stable across environments once voids are properly reweighted, tightening constraints on small-scale power that affect both primordial black hole bounds and subhalo abundance predictions.
The public Python implementation enables immediate use in semi-analytic models and mock catalog generation. Future high-resolution zoom simulations targeting the 10^8-10^10 solar mass gap will test whether the quoted 3% floor holds once baryonic back-reaction is included at all redshifts.
The formula's claimed universality will be falsified if next-generation simulations with running spectral index or light dark matter particles exceed 10% deviation below 10^{-3} solar masses by 2028.
Zheng: JWST and Euclid cluster counts will show <5% tension with the new mass function at 10^{14} solar masses by 2029 if ΛCDM holds.
Sources (3)
- [1]Primary Source(https://arxiv.org/abs/2607.05505)
- [2]Supporting Source(https://arxiv.org/abs/astro-ph/0611101)
- [3]Supporting Source(https://ui.adsabs.harvard.edu/abs/2023MNRAS.518.1891W)