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  Gaia Data Release 2 : Processing the spectroscopic data

Sartoretti, P., Katz, D., Cropper, M., Panuzzo, P., Seabroke, G. M., Viala, Y., et al. (2018). Gaia Data Release 2: Processing the spectroscopic data. Astronomy and Astrophysics, 616: A6. doi:10.1051/0004-6361/201832836.

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Sartoretti, P., Author
Katz, D., Author
Cropper, M., Author
Panuzzo, P., Author
Seabroke, G. M., Author
Viala, Y., Author
Benson, K., Author
Blomme, R., Author
Jasniewicz, G., Author
Jean-Antoine, A., Author
Huckle, H., Author
Smith, M., Author
Baker, S., Author
Crifo, F., Author
Damerdji, Y., Author
David, M., Author
Dolding, C., Author
Frémat, Y., Author
Gosset, E., Author
Guerrier, A., Author
Guy, L. P., AuthorHaigron, R., AuthorJanßen, K., AuthorMarchal, O., AuthorPlum, G., AuthorSoubiran, C., AuthorThévenin, F., AuthorAjaj, M., AuthorAllende Prieto, C. A, AuthorBabusiaux, C., AuthorBoudreault, Steve1, Author              Chemin, L., AuthorDelle Luche, C. , AuthorFabre, C., AuthorGueguen, A., AuthorHambly, N. C., AuthorLasne, Y., AuthorMeynadier, F., AuthorPailler, F., AuthorPanem, C., AuthorRiclet, F., AuthorRoyer, F., AuthorTauran, G., AuthorZurbach, C., AuthorZwitter, T., AuthorArenou, F., AuthorGomez, A., AuthorLemaitre, V., AuthorLeclerc, N., AuthorMorel, T., AuthorMunari, U., AuthorTuron, C., AuthorŽerjal, M., Author more..
1Department Solar and Stellar Interiors, Max Planck Institute for Solar System Research, Max Planck Society, ou_1832287              


Free keywords: techniques: spectroscopic / catalogs / techniques: radial velocities / surveys / methods: data analysis
 Abstract: Context. The Gaia Data Release 2 (DR2) contains the first release of radial velocities complementing the kinematic data of a sample of about 7 million relatively bright, late-type stars. Aims. This paper provides a detailed description of the Gaia spectroscopic data processing pipeline, and of the approach adopted to derive the radial velocities presented in DR2. Methods. The pipeline must perform four main tasks: (i) clean and reduce the spectra observed with the Radial Velocity Spectrometer (RVS); (ii) calibrate the RVS instrument, including wavelength, straylight, line-spread function, bias non-uniformity, and photometric zeropoint; (iii) extract the radial velocities; and (iv) verify the accuracy and precision of the results. The radial velocity of a star is obtained through a fit of the RVS spectrum relative to an appropriate synthetic template spectrum. An additional task of the spectroscopic pipeline was to provide first-order estimates of the stellar atmospheric parameters required to select such template spectra. We describe the pipeline features and present the detailed calibration algorithms and software solutions we used to produce the radial velocities published in DR2. Results. The spectroscopic processing pipeline produced median radial velocities for Gaia stars with narrow-band near-IR magnitude GRVS ≤ 12 (i.e. brighter than V ~ 13). Stars identified as double-lined spectroscopic binaries were removed from the pipeline, while variable stars, single-lined, and non-detected double-lined spectroscopic binaries were treated as single stars. The scatter in radial velocity among different observations of a same star, also published in Gaia DR2, provides information about radial velocity variability. For the hottest (Teff ≥ 7000 K) and coolest (Teff ≤ 3500 K) stars, the accuracy and precision of the stellar parameter estimates are not sufficient to allow selection of appropriate templates. The radial velocities obtained for these stars were removed from DR2. The pipeline also provides a first-order estimate of the performance obtained. The overall accuracy of radial velocity measurements is around ~200–300 m s−1, and the overall precision is ~1 km s−1; it reaches ~200 m s−1 for the brightest stars.


Language(s): eng - English
 Dates: 2018-08-292018
 Publication Status: Published online
 Pages: -
 Publishing info: -
 Table of Contents: -
 Rev. Type: Peer
 Identifiers: DOI: 10.1051/0004-6361/201832836
 Degree: -



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Title: Astronomy and Astrophysics
  Other : Astron. Astrophys.
Source Genre: Journal
Publ. Info: Berlin : Springer-Verlag
Pages: - Volume / Issue: 616 Sequence Number: A6 Start / End Page: - Identifier: ISSN: 0004-6361
CoNE: https://pure.mpg.de/cone/journals/resource/954922828219_1