High-resolution spectroscopy of RGB stars in the Sagittarius streams I. Radial velocities and chemical abundances

L. Monaco, M. Bellazzini, P. Bonifacio, A. Buzzoni, F. R. Ferraro, G. Marconi, L. Sbordone, S. Zaggia

Resultado de la investigación: Contribución a una revistaArtículo

57 Citas (Scopus)

Resumen

Context. The Sagittarius (Sgr) dwarf spheroidal galaxy is currently being disrupted under the strain of the Milky Way. A reliable reconstruction of Sgr star formation history can only be obtained by combining core and stream information. Aims. We present radial velocities for 67 stars belonging to the Sgr Stream. For 12 stars in the sample we also present iron (Fe) and α-element (Mg, Ca) abundances. Methods. Spectra were secured using different high resolution facilities: UVES@VLT, HARPS@3.6 m, and SARG@TNG. Radial velocities are obtained through cross correlation with a template spectra. Concerning chemical analysis, for the various elements, selected line equivalent widths were measured and abundances computed using the WIDTH code and ATLAS model atmospheres. Results. The velocity dispersion of the trailing tail is found to be σ = 8.3 ± 0.9 km s-1, i.e., significantly lower than in the core of the Sgr galaxy and marginally lower than previous estimates in the same portion of the stream. Stream stars follow the same trend as Sgr main body stars in the [α/Fe] vs. [Fe/H] plane. However, stars are, on average, more metal poor in the stream than in the main body. This effect is slightly stronger in stars belonging to more ancient wraps of the stream, according to currently accepted models of Sgr disruption.

Idioma originalInglés
Páginas (desde-hasta)201-209
Número de páginas9
PublicaciónAstronomy and Astrophysics
Volumen464
N.º1
DOI
EstadoPublicada - mar 2007

Áreas temáticas de ASJC Scopus

  • Ciencias planetarias y espacial
  • Astronomía y astrofísica

Huella Profundice en los temas de investigación de 'High-resolution spectroscopy of RGB stars in the Sagittarius streams I. Radial velocities and chemical abundances'. En conjunto forman una huella única.

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    Monaco, L., Bellazzini, M., Bonifacio, P., Buzzoni, A., Ferraro, F. R., Marconi, G., Sbordone, L., & Zaggia, S. (2007). High-resolution spectroscopy of RGB stars in the Sagittarius streams I. Radial velocities and chemical abundances. Astronomy and Astrophysics, 464(1), 201-209. https://doi.org/10.1051/0004-6361:20066228