This page gives details of the flags found in the GALAH DR4 catalogues. The main flags that will be of interest to most users of GALAH are the overall quality flag flag_sp and the individual abundance flag flag_X_fe.
For science cases involving stellar parameters, it is highly recommended that you only consider stars where flag_sp == 0. For science cases involving the abundance of element X, it is highly recommended that you only consider X_fe where flag_X_fe == 0 and snr_px_ccd3 > 30.
flag_sp
This flag is found in the galah_dr4_allstar_240705 (and galah_dr4_allspec_240705) catalogues and is the final bit-flag for the stellar parameter quality flag. Its value is found via the summation of the individual flags as tabulated below.
| Value | Description |
|---|---|
| 0 | No identified problems with stellar parameter determination |
| 1 | Emission lines |
| 2 | Data from at least one CCD is missing |
| 4 | Single-line spectroscopic binary |
| 8 | Double-line spectroscopic binary |
| 16 | Chi squared for the model spectrum is larger than 3 sigma |
| 32 | Warning on v sin i value |
| 64 | Warning on vmic value |
| 128 | Triple star warning |
| 256 | Warning on Teff value |
| 512 | Warning on log g value |
| 1024 | Warning on [Fe/H] value |
| 2048 | Low S/N |
| 4096 | Fit did not converge |
| 8192 | Extrapolated model; stellar parameters outside the MARCS grid |
| 16384 | No analysis results |
flag_X_fe
These flags are found in GALAH_dr4_allstar_240705 and are the final bit-flag for the elemental abundance quality for the elemental abundance X_fe. Their values are found via the summation of the individual flags as tabulated below.
| Value | Meaning |
|---|---|
| 0 | No identified problems with abundance determination of element X_fe |
| 1 | Value is an upper limit |
| 2 | Line is not detectable |
| 4 | Fit did not converge |
| 8 | Value above the analysis limit |
| 16 | Value below the analysis limit |
| 32 | Measurement issue with C, N, or O |
| 64 | Measurement issue with Li, Ca, or Ba |
Other flags
There are a number of other flags found in the GALAH catalogues. Most are only of interest for expert users.
flag_red
The spectrum reduction pipeline quality flag.
flag_sp_fit
A diagnostic flag from the analysis pipeline.
flag_fe_h
A diagnostic flag from the analysis pipeline. Its value is found via the summation of the individual flags as tabulated below. However, there is an error in the upper limit bit, and this flag should not be used in its current state.
| Value | Meaning |
|---|---|
| 0 | No identified problems with determination of fe_h |
| 1 | Value is an upper limit |
| 2 | No measurement available |
| 4 | Fit did not converge |
| 8 | Value above the analysis limit |
| 16 | Value below the analysis limit |