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: Article

55 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 originalEnglish
Páginas (desde-hasta)201-209
Número de páginas9
PublicaciónAstronomy and Astrophysics
Volumen464
N.º1
DOI
EstadoPublished - mar 2007

Huella dactilar

radial velocity
spectroscopy
stars
high resolution
wrap
dwarf galaxies
chemical analysis
cross correlation
chemical
star formation
templates
histories
galaxies
trends
iron
atmospheres
atmosphere
metal
estimates
history

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Citar esto

Monaco, L. ; Bellazzini, M. ; Bonifacio, P. ; Buzzoni, A. ; Ferraro, F. R. ; Marconi, G. ; Sbordone, L. ; Zaggia, S. / High-resolution spectroscopy of RGB stars in the Sagittarius streams I. Radial velocities and chemical abundances. En: Astronomy and Astrophysics. 2007 ; Vol. 464, N.º 1. pp. 201-209.
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title = "High-resolution spectroscopy of RGB stars in the Sagittarius streams I. Radial velocities and chemical abundances",
abstract = "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.",
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Monaco, L, Bellazzini, M, Bonifacio, P, Buzzoni, A, Ferraro, FR, 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, vol. 464, n.º 1, pp. 201-209. https://doi.org/10.1051/0004-6361:20066228

High-resolution spectroscopy of RGB stars in the Sagittarius streams I. Radial velocities and chemical abundances. / Monaco, L.; Bellazzini, M.; Bonifacio, P.; Buzzoni, A.; Ferraro, F. R.; Marconi, G.; Sbordone, L.; Zaggia, S.

En: Astronomy and Astrophysics, Vol. 464, N.º 1, 03.2007, p. 201-209.

Resultado de la investigación: Article

TY - JOUR

T1 - High-resolution spectroscopy of RGB stars in the Sagittarius streams I. Radial velocities and chemical abundances

AU - Monaco, L.

AU - Bellazzini, M.

AU - Bonifacio, P.

AU - Buzzoni, A.

AU - Ferraro, F. R.

AU - Marconi, G.

AU - Sbordone, L.

AU - Zaggia, S.

PY - 2007/3

Y1 - 2007/3

N2 - 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.

AB - 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.

KW - Galaxies: abundances

KW - Galaxies: dwarf

KW - Galaxies: evolution

KW - Galaxies: individual: Sgr dSph

KW - Stars: abundances

KW - Stars: atmospheres

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U2 - 10.1051/0004-6361:20066228

DO - 10.1051/0004-6361:20066228

M3 - Article

AN - SCOPUS:33947121529

VL - 464

SP - 201

EP - 209

JO - Astronomy and Astrophysics

JF - Astronomy and Astrophysics

SN - 0004-6361

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