>[!warning]
>This content has not been peer reviewed.
# SPARC Evaluation — Results Summary
Summary of the RST gravity-sector fit to the SPARC database. **Method and data:** **[[expanded theory/python calculations/SPARC Evaluation - Code|SPARC Evaluation - Code]]**. **Implementation:** **[[about systems/expanded theory/sparc evaluation/README|sparc evaluation/]]** (rst + notebooks). Data: [SPARC](http://astroweb.cwru.edu/SPARC/) (Lelli et al. 2016; see citation below).
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## Citation
**Data and method:** Lelli, F., McGaugh, S. S., & Schombert, J. M. (2016). *SPARC: Mass models for 175 disk galaxies with Spitzer photometry and accurate rotation curves.* Astron. J. 152, 157. [arXiv:1606.09251](https://arxiv.org/abs/1606.09251). Data: [http://astroweb.cwru.edu/SPARC/](http://astroweb.cwru.edu/SPARC/).
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## Summary
| Metric | Value |
|:---|:---|
| Galaxies fitted | 171 |
| $\Upsilon_{\text{disk}}$ median | 0.52 |
| $\Upsilon_{\text{disk}}$ mean | 0.68 |
| $\chi^2_{\text{red}}$ median | 1.60 |
| $\chi^2 < 2$ | 58% (99 galaxies) |
| $\chi^2 < 5$ | 80% (136 galaxies) |
| $\chi^2 < 10$ | 86% (147 galaxies) |
**Note on $\Upsilon_{\text{disk}}$:** The median from this evaluation run is 0.52. Other runs (e.g. calibration with fixed $n$, or different bounds) report median ≈ 0.49–0.491, often cited as "SPS-matched" (stellar population synthesis $\sim 0.5 \pm 0.1$). The spread 0.49–0.52 is run- and sample-dependent; both lie within the expected SPS range.
**RST parameters (fixed):** $a_0 = 1.042 \times 10^{-10}$ m/s² (from $cH_0/(2\pi)$), $n = 1.25$ (calibrated from transition-zone galaxies). No dark matter halo parameters.
**Interpretation:** **[[expanded theory/python calculations/SPARC Evaluation Verification]]**. **Method:** **[[expanded theory/python calculations/SPARC Evaluation - Code]]**. **Code (rst + notebooks):** **[[about systems/expanded theory/sparc evaluation/SPARC evaluation - Code]]**. Outputs (plots, CSV) are in `expanded theory/sparc evaluation/notebooks/output/`. Full predictions vs data index: **[[Predictions and data matching]]**.
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## Summary graphic
![[sparc_summary.png]]
![[highz_prediction.png]]
![[rar_local.png]]
![[rotation_curve.png]]
![[sparc_filtered_summary.png]]![[sparc_float_n_summary.png]]![[sparc_summary.png]]
![[sparc_n2_summary.png]]