GALAH Data Release 2 Overview
This release is deprecated and superseded by Data Release 3.
The GALAH survey released our second data release on 18 April 2018. It contains data for 342682 stars with up to 23 elemental abundances per star.
Update: On 9 May 2018 we released the GALAH survey DR2.1. This contains a fix to three columns related to radial velocities, populates the gaia_dr2_id column, and adds a collection of high-SNR median spectra. See the changelog for more details.
The catalogue is accessible through:
- The query services on the AAO Data Central webpage
- TAP via https://datacentral.org.au/vo/tap
- Direct download (the median spectra are also downloadable here)
There are a number of important documents that describe this release:
What's in GALAH DR2?
GALAH DR2 contains stellar parameters and abundances for 342682 stars observed as part of the main GALAH survey between 2014 January 16 and 2018 January 29.
The initial catalogue for GALAH DR2 is quite straightforward:
- All stars from the GALAH main survey (field_id 0 through 6545)
Stars are then excluded from the DR2 catalogue if any of the criteria below are met:
- The data reduction pipeline failed to measure rv_synt (radial velocity from cross-correlation against a grid of synthetic spectra)
- The e_rv_synt uncertainty is above 3 km/s
- If fewer than 5 stars in a single configuration successfully achieved parameter estimation through cross-correlation against a grid of synthetic spectra, all stars from that configuration are rejected
It is unusual for us to have multiple observations of a particular star, and for stars observed multiple times we include only the observation with the highest signal to noise ratio in the DR2 catalogue.
The 23 elements for which we provide abundances are (and their dominant nucleosynthetic origin):
- light elements: Li, C, O
- odd-Z elements: Na, Al, K
- α-elements: Mg, Si, Ca, Ti
- iron-peak elements: Sc, V, Cr, Mn, Fe, Co, Ni, Cu, Zn
- light and heavy slow neutron capture elements: Y, Ba, La
- rapid neutron capture element: Eu
Questions about DR2? Email Sarah Martell, s.martell -at- unsw.edu.au