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# Documentation

Find information, examples, FAQs and extensive descriptions of the data, curated by the survey teams.

#### GALAH

The Galactic Archaeology with HERMES survey is collecting stellar parameters and abundances for one million stars in the Milky Way. GALAH yields a comprehensive view of the formation & evolution of the Galaxy.
Nov. 6, 2020 by J. Simpson
May 5, 2021, 10:55 a.m. J. Simpson

GALAH DR3

## Quick start

Do you want the entire GALAH DR3 catalogue of stellar parameters and abundances for your research?

We recommend you use the galah_dr3.main_star catalogue. This catalogue can be directly downloaded from here (it has the file name GALAH_DR3_main_allstar_v2.fits), or by using wget (removing the --spider flag):

wget --spider https://cloud.datacentral.org.au/teamdata/GALAH/public/GALAH_DR3/GALAH_DR3_main_allstar_v2.fits

For science cases involving stellar parameters, it is highly recommended that you only consider stars where flag_sp == 0 and flag_fe_h == 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_c3_iraf > 30. See the Using GALAH Data page for helpful guide to the tables and our recommendations.

### GALAH DR3 Catalogue Summary

We provide two versions of the main GALAH DR3 catalogue, and several value-added catalogues. See also the documentation on the Table Schema, and the Value-Added Catalogues.

Catalogue name File name File size Description
galah_dr3.main_star GALAH_DR3_main_allstar_v2.fits 833 MB Strongly recommend the use of this catalogue. One entry per star observed. Radial velocity, stellar parameters and abundance data. Important data from Gaia, 2MASS, and WISE.
galah_dr3.main_spec GALAH_DR3_main_allspec_v2.fits 2.1 GB One entry per observation. Radial velocity, stellar parameters for each observation. Also contains abundances derived for each individual line. Important data from Gaia, 2MASS, and WISE.
galah_dr3.vac_gaiaedr3 GALAH_DR3_VAC_GaiaEDR3_v2.fits 338 MB Gaia eDR3 data for all stars in GALAH DR3
galah_dr3.vac_ages GALAH_DR3_VAC_ages_v2.fits 362 MB Ages, masses, distances and other parameters estimated using isochrones
galah_dr3.vac_dynamics GALAH_DR3_VAC_dynamics_v2.fits 554 MB Galactic kinematic and dynamic parameters
galah_dr3.vac_rv GALAH_DR3_VAC_rv_v2.fits 67 MB Collated radial velocity measurements
FGK binary stars Identification of likely for double-lined spectroscopic binaries. This VAC is served on the Centre de Données astronomiques de Strasbourg rather than Data Central.
galahfco target/galahfco_3_public.txt 957 kB List of fields and field configurations. Each field has a unique ra, dec coordinates and field_id. Multiple configurtations can have same field_id.

### Accessing the catalogues

There are two methods for accessing these catalogues depending on your requirements

#### The entire catalogues

The catalogues listed above can be downloaded in their entirety as FITS files here, or using the following command (removing the --spider flag and replacing with the appropriate file name from the table above)

# Download the galah_dr3.main_star catalogue
wget --spider https://cloud.datacentral.org.au/teamdata/GALAH/public/GALAH_DR3/GALAH_DR3_main_allstar_v2.fits

#### ADQL query

The catalogues can be accessed using the query services provided by Data Central. For example, if you are interested in all of the entries for stars likely to be members of the globular cluster omega Centauri, these could be found using a query like:

SELECT
TOP 100
*
FROM galah_dr3.main_star
WHERE
1=CONTAINS(POINT('ICRS', ra, dec),
CIRCLE('ICRS', 201.6836, -47.5068, 1.0 ))
AND sqrt(power(pmra-(-3.2),2)+power(pmdec-(-6.9),2)) < 1.5
AND rv_galah > 170

The catalogues of GALAH DR3 must be joined or cross-matched using the sobject_id. Do not use Gaia source_id or the star_id for joining catalogues. These value-added catalogues are based upon the extended catalogue which contains measurements per observed spectrum. About 50000 stars were observed multiple times, and therefore have multiple observed spectra. The sobject_id column is our internal ID for each observation and using this column for joining will ensure that you are matching information derived from the same spectrum. For instance, to join the galah_dr3.main_star to the value-added catalogue of ages (galah_dr3.vac_ages), the following ADQL query could be used:

SELECT
TOP 100
g_ms.source_id, g_ages.sobject_id, g_ages.age_bstep, g_ages.e_age_bstep
FROM galah_dr3.main_star AS g_ms
JOIN galah_dr3.vac_ages AS g_ages
ON g_ms.sobject_id = g_ages.sobject_id
Nov. 6, 2020 by J. Simpson
May 5, 2021, 10:55 a.m. J. Simpson