SPARC Rotation Curve Fits: VMS vs NFW vs MOND

Single-script, publication-ready comparison of three galaxy rotation-curve models using SPARC data:
* VMS (Zhao n=0 spherical profile) Ð 1 free parameter (??)
* NFW Ð 1 free parameter (?_s)
* MOND Ð 0 free parameters (a? fixed at 1.2?10??? m/s?)

All units match the SPARC standard system (Nov 2025 version).

Requirements

Python 3.8+, NumPy, Pandas, SciPy
(standard on any scientific stack)

Data

Download the SPARC database from:
http://astroweb.cwru.edu/SPARC/

Unzip and place all *Rotmod.dat files in:
./sparc_data/
The script automatically handles both 5-column and 6-column SPARC formats.

Quick Start

Run a single-galaxy test:
python vms_analysis.py
This prints ??, RMS, and fitted parameters for VMS, NFW, and MOND.

A CSV summary is generated when the multi-galaxy batch runner is enabled.

Notes
* All models use explicit baryonic velocity V_bar as the base curve.
o MOND modifies it directly.
o VMS/NFW add a DM halo on top: v_total? = v_bar? + v_DM?.
* Errors are handled with a small floor (0.5 km/s) to avoid zero-? failures in SciPy.
* The script is intentionally minimal: no plotting, no GUI, nothing hidden.

Batch Mode (Optional)

At the bottom of the file, enable:
galaxy_list = ['UGC02259', 'NGC3198', 'NGC2403', ...]
This runs VMS, MOND, and NFW on each galaxy and saves:
sparc_vms_mond_nfw_summary.csv
Users are welcome to send their results or plots to the VMS Institute for inclusion on the website or to publish independently.