The ELODIE Archive
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The ELODIE Archive


Introduction

This archive aims to preserve all data taken with the ELODIE spectrograph for long-term usage and to make it available through the Web in a readily useable form.

ELODIE was an echelle spectrograph used at the 1.93m telescope of Observatoire de Haute Provence (OHP) between late 1993 and mid 2006. The instrument was open to visiting observers on 1 August 1994. It was designed for very precise radial-velocity measurements (the discovery of the first extra-solar planet, 51 Peg B, by Mayor and Queloz in 1995 was made using Elodie spectra) but has also been used for many programs in stellar physics and galactic structure.

Principal investigators are now granted exclusive rights to data taken with OHP telescopes for a period of one year. Thereafter they are made automatically available to the astronomical community (a longer period of 5 years applies to the search for extra-solar planet programs).

The spectra have a nominal resolution of R=42000. Only data with a S/N (@5500 Å) > 3 have entered the archive. They can be visualized on-screen or downloaded in FITS format and can be re-processed on the fly. This re-processing allows in particular to reconnect the echelle orders, to resample the data in wavelength, and to correct for the incomplete removal of the instrument signature.

For more detailed information about Elodie spectra and about archive data products, please read the Elodie for Dummies page. See also the page on More advanced ways to access the Elodie archive.

Object identification and search criteria

The archive can be interrogated using either (1) object naming conventions or (2) positions. For example HD141569, BD+292355, HIP062384, GJ_719, VV_Ser, Arcturus, MOON, J17:28:50.1 +00:19:15 or J154958.1-035515 are all valid search criteria. In the case of positions, the search is carried in a region around the coordinates given by the user.

In preparing the archive we have strived to label as much science data as possible with a meaningful object name. In doing so we have relied first on the name and catalog coordinates given by the observer and second on the telescope coordinates. The results may not always be satisfactory due to unrecognized or unavoidable errors. We hope to solve these problems in the forthcoming future. User feedback is requested here.

Contents of the archive

Update : All data in the Archive (35535 spectra) are public since August 2011.

As of April 2009 the archive contained nearly 35000 spectra with S/N > 5 in V (5500 Å), originally stored on 400 CD-ROMs (since October 1995), with some data stored on DAT tapes previous to this. The archived data were taken between 8 July 1994 and 13 August 2006. There are more than 7700 distinct object names, but the actual number of distinct objects is probably closer to 3000, due to the use of different aliases for the same star that we did not yet resolve. A cross-identification process is in progress to remove these aliases. The histogram at left shows the early distribution of the signal-to-noise ratio (at 5500 Å) for the whole sample of archive spectra. Note the peak near S/N=40.

Gallery

See a brief presentation of archive data products for information about the different formats available.

The team and their responsibilities

Philippe Prugniel (CRAL, Lyon Obs.) Pleinpot and PostgreSQL software
Caroline Soubiran (Bordeaux Obs.) [Fe/H] data and cross-identifications
Sergio Ilovaisky (OHP) local management of database
Jihanne Moultaka and Mina Koleva have contributed to the project.

Future evolution

The ELODIE spectrograph was replaced in August 2006 by a new instrument, SOPHIE, with improved capabilities in terms of stability and limiting magnitude. We plan to extend the present archive to host the spectra from SOPHIE.

In the meantime, the content of the Elodie archive will continue to be updated and efforts are undertaken to improve the quality assessment of the material and the quality of the cross-identifications...

New processing functions may also become available and links with other projects will be developed. See for example the page on upcoming features.

Questions and feedback

We encourage feedback from all users. Please address all questions and remarks to ohp.database AT osupytheas.fr.

Use of data retrieved

The data in the Elodie archive are made freely available to the astronomical community but remain the property of the Observatoire de Haute-Provence (OHP). Any organized re-distribution of the spectra retrieved from the archive is unauthorized. Commercial use is strictly prohibited without our prior agreement.

Publications based on data obtained from this archive should be accompanied by the statement: "Based on spectral data retrieved from the ELODIE archive at Observatoire de Haute-Provence (OHP)". The paper by Moultaka et al. (2004) PASP, 116, 693 should be cited in the bibliography. A list of papers based on ELODIE archival data is now available.

Acknowledgements

We thank the MIGALE project who develop and distribute the Pleinpot package on which the present project is built. Pleinpot is itself using several open sources packages and in particular fitsio and PostgreSQL which are very important in the framework of the current project.

We acknowledge the use of the Simbad (© ULP) and HyperLeda databases for checking the cross-identifications and decoding the designations provided by the users.

This project is supported by Observatoire Astronomique de Marseille Provence (OAMP), Programme National de Physique Stellaire (PNPS) and Observatoire de Haute-Provence (INSU-CNRS). The project would not have been feasible without the long term efforts of the OHP staff to maintain and secure copies of all the observations on DAT or CD-ROM.


S.A.Ilovaisky
revised version: 23 January 2013