a LEGACY-type data base of spectropolarimetric data

© JF Donati

A homogeneous set of ESPaDOnS/CFHT and NARVAL/TBL spectra

All ESPaDOnS/CFHT and NARVAL/TBL spectra collected during allocated runs will be reprocessed in a homogeneous way with Libre_ESpRIT, the dedicated spectropolarimetric reduction package especially designed for ESPaDOnS and NARVAL data. Spectra are reduced using Optimal Extraction as devised by Horne & Marsh and include error bar estimates at all wavelength pixels.

The collected reduced spectra will feed a database, to be accessible by the entire astrophysical community. This database is expected to be very useful for most studies in stellar & solar physics, just as databases of synthetic spectra or atmospheric models are nowadays; it should also be very useful to investigate a posteriori, eg secular changes in the properties of stars of given stellar classes. This database should also provide a new source of reliable information to other domains of astrophysics, like for instance atomic physics (eg to investigate the formation and properties of molecular lines) or galactic physics (eg to study stellar populations from high resolution composite spectra of galaxies). This database thus clearly features a LEGACY dimension; as for the HST database, we expect that it will also further increase the impact of spectropolarimetric data and associated instruments in terms of refereed publications and citations.

Automatic spectral classification

We are building up an Automatic Spectral Classification tool based on the MATISSE (Recio-Blanco et al, 2006, MNRAS 370, 141) algorithm (sharing similarities with Principal Component Analysis). Ultimately, this tool should yield accurate stellar atmospheric parameters for all reduced ESPaDOnS/NARVAL spectra, from a comparison to both synthetic spectra (POLLUX data base) and observed reference stellar spectra (collected with ESPaDOnS and NARVAL).

The complete data base

The complete data base will include each observed spectrum, the corresponding Least-Squares Deconvolution (LSD, Donati et al 1997, MNRAS 291, 658) profile and all relevant characteristics derived either from LSD profiles (rotation and radial velocity, binary, magnetic field detection), from the automatic spectral classification tool (effective temperature, logarithmic gravity, metallicity, veiling), from comparisons to stellar evolution models (mass, radius, age) and from comparisons of multiple exposures (variability).
The data base will be accessible to the whole astronomical community and will feature links to the SIMBAD and POLLUX databases. The first version of this database should be operational in 2008/2009 - it will then be regularly updated, with new spectra brought online as soon as they enter public domain.

Possible extensions

Possible extensions to other spectropolarimetric data sets (eg FORS1, MuSiCoS) are being discussed.

Core team and collaborators

Thread coordinator: P Petit, A Lèbre, S Bagnulo, D Bohlender
Agency/Country Core team Collaborators
F Aurière, Bouret, Donati, Josselin, deLaverny, Lèbre, Martins, Mathias, Neiner, Palacios, Petit, Recio-Blanco, Soubiran
O Bagnulo Bailer-Jones
C Bohlender, Landstreet, Wade
US Valenti