Data products

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The Survey will yield GIRAFFE spectra for around 105 stars, UVES spectra for around 104 stars, most of which are observed at two different epochs. Raw data will automatically be public. The products to be delivered during Phase 3 include extracted spectra, with relevant ancillary information, and value added deliverables, along with information on the data.

The Survey requires several observations of each target star to provide sufficient information to initiate spectrum processing and analysis. Thus we distinguish carefully between the time when a spectrum is taken, and the time when all spectra for a target are delivered, at suitable signal to noise ratio (SNR). It is this second date which initiates the timing for release of advanced data products. See also Timeline for delivery of data products to the ESO archive. Regular data releases to ESO will include, for all targets with completed observations:

1. Semester Advanced Data Product Releases

These are the outputs of Working Groups 1-9.

  • One-dimensional, wavelength calibrated, sky-subtracted, normalised, UVES and/or GIRAFFE spectra for each Survey target, extracted using the current ESO pipelines. Where no radial velocity (RV) variability is detected, co-added sum spectra will be provided, in addition to single-epoch spectra. UVES spectra will be provided as sets of single echelle orders and a merged spectrum
  • The associated variance spectrum
  • Associated quality control information
  • Supplementary value-added data:

    • The photometry (and additional membership information for clusters) used to select the targets
    • Object classification
    • Radial velocity and its error distribution function
    • Analysis for RV variability
    • Projected rotational velocity and error estimate (where relevant).

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2. Annual Advanced Data Product Releases

Advanced data products from expanded and refined spectral analysis, calibrated using the current Gaia-ESO calibrations. These are the outputs of iterative homogenization and quality control involving Working Groups 10-15, and science verification analysis.

For stars observed with GIRAFFE:

  • Whenever possible stellar astrophysical parameters: effective temperature, surface gravity
  • Equivalent widths of absorption and emission lines (when present)
  • Whenever possible stellar metallicity [Fe/H]
  • Whenever possible [α/Fe] ratios
  • Measurements of stellar activity or mass accretion/ejection rates, for cluster members (where relevant)
  • Quantitative mass loss estimates, for early-type stars
  • Elemental abundances, with the specific elements depending on target type
  • Quantitative uncertainties on the delivered quantities, derived from the multiple reduction systems implemented.

For stars observed with UVES:

  • Stellar astrophysical parameters: effective temperature, surface gravity, microturbulence
  • Stellar metallicity [Fe/H]
  • Equivalent widths of absorption and emission lines (when present)
  • Elemental abundance estimates for some or all of the following elements (where stellar abundance and astrophysical parameters permit) Li, C, O, Na, Mg, Si, Ca, Sc, Ti, Cr, Mn, Ni, Zn, Y, Zr, Ba, La, Ce, Eu
  • Chromospheric activity measurement, when relevant
  • Quantitative uncertainties on all the above parameters, derived from the multiple reduction systems implemented.

The data release will also include selected matched multi-wavelength photometric data for each source. The amount of such data will increase with time during the Survey as on-going surveys become public.

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3. Final Advanced Data Product Release

This final data-release will include best values for all deliverables listed above for all stars, calibrated onto the final Gaia-ESO calibration system. In addition, for open cluster members, it will include

  • Average RV for the clusters
  • Refined membership classification
  • Binarity flags
  • Cluster mean metallicity determinations with standard deviation
  • Cluster mean elemental abundances with standard deviations.

Following the agreed schedule, and after validation and Co-PI sign-off, the Survey products will be delivered to the ESO Science Archive Facility (SAF) during Phase 3 and will comply with the data standards and policies which are published on Each release will be supported by a release description that specifies content, data properties, and format.

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Page last updated: 19/03/2013