PreprintCC BY 4.0Zenodo
Why the Baryonic Tully-Fisher Slope is Not 4
- 1Artificial Epistemology
Abstract
MOND predicts that the baryonic Tully-Fisher relation (BTFR) has an exact slope of n = 4. Two independent 2026 analyses of SPARC galaxies reject this prediction at ≥4σ, finding n = 3.47 ± 0.10 (135 galaxies, ODR) and n = 3.50 ± 0.11 (175 galaxies, MCMC). We show that a mass-dependent MOND acceleration scale predicts n = 4/(1+x), which is necessarily less than 4. For x ≈ 0.15, consistent with our independent measurement from rotation curve fitting, n = 3.48. One equation, one parameter, two measurements explained. The BTFR slope joins the cluster mass discrepancy as a second independent line of evidence for mass-dependent a₀.
Related
- The baryonic Tully-Fisher relation as an independent direct probe of cosmology and of the nature of dark matter
- Systematic uncertainties on DESI Tully-Fisher distances constrained with Integral Field Spectroscopy
- The ALPINE-CRISTAL-JWST Survey: The Tully-Fisher Relation at z = 4−6
- TULLY World 41: Documented Experimental Series
- A φ-Parameterized Bounded Phase Gate for Structured Residual Modulation Ablation-Ready Research Scaffold for the TULLY / Ly-Algebra Lineage
BibTeX
@misc{pec2026baryonic,
title = {{Why the Baryonic Tully-Fisher Slope is Not 4}},
author = {Philip AE Pec and Bebop},
howpublished = {Zenodo},
year = {2026},
month = oct,
doi = {10.5281/zenodo.23591229},
url = {https://zenodo.org/records/23591229},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Why the Baryonic Tully-Fisher Slope is Not 4
AU - Philip AE Pec
AU - Bebop
PY - 2026
DA - 2026/10/23
PB - Zenodo
DO - 10.5281/zenodo.23591229
UR - https://zenodo.org/records/23591229
AB - MOND predicts that the baryonic Tully-Fisher relation (BTFR) has an exact slope of n = 4. Two independent 2026 analyses of SPARC galaxies reject this prediction at ≥4σ, finding n = 3.47 ± 0.10 (135 galaxies, ODR) and n = 3.50 ± 0.11 (175 galaxies, MCMC). We show that a mass-dependent MOND acceleration scale predicts n = 4/(1+x), which is necessarily less than 4. For x ≈ 0.15, consistent with our independent measurement from rotation curve fitting, n = 3.48. One equation, one parameter, two measurements explained. The BTFR slope joins the cluster mass discrepancy as a second independent line of evidence for mass-dependent a₀.
ER -