>[!warning] >This content has not been peer reviewed. # SPARC data **Citation:** If you use this data in scientific work, cite the SPARC primary paper: > Lelli, F., McGaugh, S. S. & Schombert, J. M. (2016). *SPARC: Mass Models for 175 Disk Galaxies with Spitzer Photometry and Accurate Rotation Curves.* AJ 152, 157. [arXiv:1606.09251](https://arxiv.org/abs/1606.09251). [ADS](https://ui.adsabs.harvard.edu/abs/2016AJ....152..157L/abstract) References to the original HI+Hα rotation curves are in Table1.mrt on the SPARC site. Cite the original rotation-curve sources when relevant. **Download:** [http://astroweb.cwru.edu/SPARC/](http://astroweb.cwru.edu/SPARC/) --- ## Mass-model columns Each galaxy file (e.g. `NGC6503_rotmod.dat`) typically contains: | Column | Description | |:---|:---| | `Rad` | Radius (kpc) | | `Vobs` | Observed rotation velocity (km/s) | | `errV` | Velocity uncertainty (km/s) | | `Vgas` | Gas contribution (km/s) | | `Vdisk` | Stellar disk contribution (km/s) | | `Vbul` | Bulge contribution (km/s) | Place the rotmod files in this folder. --- ## Newtonian acceleration The Newtonian acceleration at each radius is computed as: $g_N(r) = \frac{V_{\text{gas}}^2 + \Upsilon_{\text{disk}}\, V_{\text{disk}}^2 + \Upsilon_{\text{bul}}\, V_{\text{bul}}^2}{r}$ where $\Upsilon$ is the mass-to-light ratio (often fixed at 1.0 for a first pass; see **[[about systems/expanded theory/sparc evaluation/SPARC evaluation - Code]]** and **[[../../python calculations/SPARC Evaluation - Code]]**).