# M31 CGMsum v19 primary-measurement data dictionary

This reader-facing table contains the 14 primary dual-MOS fields.
Frozen source file: `independent_cgm_v19_primary_dual_mos_measurements.csv`.
Frozen source SHA-256: `0f8ecd9fb3f183f00f364a2dd216a4b51e1a6ed299d3ac2f1d8623a3820280b9`.
The `cgmsum_*` columns are the preferred public fields. The corresponding
`mwhalo_*` columns are retained unchanged as historical frozen-fit fields
for provenance; each alias is byte-for-byte equal to its historical source.
No fit, flux, quality flag, or frozen source CSV is modified.

| Preferred public field | Historical frozen-fit field |
|---|---|
| `cgmsum_kt_keV` | `mwhalo_kt_keV` |
| `cgmsum_kt_err_keV` | `mwhalo_kt_err_keV` |
| `cgmsum_norm` | `mwhalo_norm` |
| `cgmsum_norm_err` | `mwhalo_norm_err` |
| `cgmsum_cov_kt_norm` | `mwhalo_cov_kt_norm` |
| `v18_cgmsum_kt_keV` | `v18_mwhalo_kt_keV` |
| `v18_cgmsum_kt_err_keV` | `v18_mwhalo_kt_err_keV` |
| `v18_cgmsum_norm` | `v18_mwhalo_norm` |

The historical component name does not establish a Milky-Way distance.
Throughout the manuscript, CGMsum denotes the directly measured cool
line-of-sight component, potentially containing MW, M31, and named
Local-Group contributions.