Goal
The goal of the AMBRE project is to homogeneously determine the stellar parameters (and chemical indices) from all the stellar high and medium resolution spectra (from the FEROS, HARPS, UVES and FLAMES spectrographs) available in the ESO archive. The results of the AMBRE project will be made available to the international community through the ESO archive and the Virtual Observatory. From this analysis of the largest existing high resolution spectra archive, we will derive a chemical map of the Milky Way based on very homogeneously derived data. New constraints on the formation history of the Galaxy, mainly from its chemical characteristics, will be derived from these data.
Method
AMBRE is building up on the experience of our group with automated stellar-parameters determination from spectroscopy (developed in the framework of the Gaia DPAC). Such methods will be needed by all future projects on galactic archaeology, to chemically analyse large amounts of stars in order to characterize the different stellar populations. For this purpose, we have developed the MATrix Inversion for Spectral SynthEsis (MATISSE, Recio-Blanco et al., 2006) algorithm. The MATISSE method is an automated procedure for the derivation of atmospheric parameters (Teff, log g, [M/H]) and individual chemical abundances from stellar spectra. The parameters are estimated by projections on relevant functions derived from a multi-linear regression. MATISSE is currently part of the stellar spectroscopic parametrization pipeline of the Gaia Data Processing and Analysis consortium and it is being applied with success to other projects concerning large samples of VLT/FLAMES spectra (Gazzano et al. 2009, in preparation; Recio-Blanco et al. 2009, oral presentation).
Archival data
The project is based on analysing ESO’s high (and medium) resolution public archive. ESO is providing pipeline products, to a stage of 1-D, extracted, wavelength-calibrated, merged spectra.
- FEROS:
- FEROS archive, comprising spectra from 2005 to 2008 included.
- 26000 spectra
- Delivered by ESO in 2009
- HARPS
- UVES
- FLAMES
