Value-Added Catalogues
GALAH DR2
Median spectra
In GALAH, we determine radial velocity in two ways: through cross-correlation against a grid of synthetic spectra, and through cross-correlation against median GALAH spectra constructed for small well-populated regions in Teff - log(g) - [Fe/H] space.
The median spectra are a high-quality empirical spectral library for stars in well-populated regions of the H-R diagram, in bins with width 50 K in Teff, 0.2 dex in log(g) and 0.1 dex in [Fe/H]. There are 1277 such median spectra, composed of between 103 and 2276 individual GALAH spectra. A file containing all of the median spectra can be downloaded from this link.
A paper describing the median spectra and the RV determination is available on arXiv.