Regime-Dependent Validity in Energy-Flow Cosmology: Evidence from SPARC Galaxy Rotation Curves and the EFC-R Framework

AbstractBackground: Energy-Flow Cosmology (EFC) offers a thermodynamic alternative to dark matter for explaining galaxy rotation curves. However, previous applications have shown inconsistent performance across different galaxy types, with no systematic understanding of when or why EFC succeeds or fails.Methods: We analyzed 20 galaxies from the SPARC database spanning diverse morphological types (LSB, dwarf, spiral, barred). For each galaxy, we fit both EFC and standard ΛCDM models, comparing performance via the Akaike Information Criterion (ΔAIC). We constructed a phenomenological "latent field proxy" to quantify structural complexity and tested for correlations with model preference.Results: EFC performance shows clear morphological stratification: 100% success for LSB galaxies, 80% for dwarfs, 70% for spirals, and 0% for barred/disturbed systems. The correlation between structural complexity and ΔAIC is statistically significant (Spearman ρ = 0.705, p = 0.0005). A tipping-point-like regime transition is observed around L ≈ 0.5.Interpretation: We introduce the EFC-R framework—not as a replacement for EFC, but as a domain-of-validity layer. EFC-R distinguishes between "flow-dominated" regimes (α → 1, EFC valid) and "latent-dominated" regimes (α → 0, EFC invalid) through the decomposition E_total = E_flow + E_latent. EFC-R is proposed as an empirically-motivated interpretive framework; its mathematical completion is left for future work.Scope: This is a pilot study (N=20). Results apply only at galactic scales; cosmological-scale constraints (e.g., CMB, BAO) remain outside scope. Independent validation on larger samples is essential before drawing definitive conclusions.Data Source: SPARC database (Lelli, McGaugh & Schombert 2016, AJ 152, 157)Project URL: https://energyflow-cosmology.com/