Can velocity-dependent dark-matter self-interaction satisfy small-galaxy and cluster constraints simultaneously?
Public summary of an internal test, not yet independently validated or published.
Question investigated
Can velocity-dependent dark-matter self-interaction satisfy small-galaxy and cluster constraints simultaneously?
Test conditions
Assess the velocity dependence of self-interaction using the galactic ranges and published cluster limits. Comparison with a baryonic explanation requires fitting the halo models to each galaxy and performing a hierarchical comparison, which has not yet been completed.
Result
An approximately inverse dependence on velocity is compatible with the ranges examined: median exponent −0.973 and a 95% interval from −1.921 to −0.476. Because the decisive model comparison was not calculated, these values do not establish a preference for self-interaction over the baryonic alternative.
Key figure
Exponent
-0.973
[-1.921, -0.476]
Median exponent
Source: Tower public snapshot
Specific limitations
- This test assesses phenomenological compatibility across velocity scales. Uncertainties in the modeling of stars and gas remain relevant to the comparison of halo models.
- The plot shows the median and 95% interval of the exponent. The source does not specify whether the interval is frequentist or Bayesian. Without the normalization and individual data, the interaction curve as a function of velocity cannot be determined. The decisive model comparison remains pending.