Chemical abundances in the nucleus of the Sagittarius dwarf spheroidal galaxy

A. Mucciarelli, M. Bellazzini, R. Ibata, D. Romano, S. C. Chapman, L. Monaco

Resultado de la investigación: Article

11 Citas (Scopus)

Resumen

We present iron, magnesium, calcium, and titanium abundances for 235 stars in the central region of the Sagittarius dwarf spheroidal galaxy (within 9:00∼70 pc from the centre) from medium-resolution Keck/Deep Imaging Multi-Object Spectrograph spectra. All the considered stars belong to the massive globular cluster M 54 or to the central nucleus of the galaxy (Sgr, N). In particular we provide abundances for 109 stars with [Fe/H] ≥-1:0, more than doubling the available sample of spectroscopic metallicity and-elements abundance estimates for Sgr dSph stars in this metallicity regime.We find for the first time a metallicity gradient in the Sgr,N population, whose peak iron abundance goes from [Fe/H] =-0:38 for R ≤2:50 to [Fe/H] =-0:57 for 5:0 < R 9:0. On the other hand, the trends of [Mg/Fe], [Ca/Fe], and [Ti/Fe] with [Fe/H] are the same over the entire region explored by our study.We reproduce the observed chemical patterns of the Sagittarius dwarf spheroidal as a whole with a chemical evolution model which implies that a high mass progenitor (MDM = 6 1010 M) and a significant event of mass-stripping occurred a few Gyr ago, presumably starting at the first peri-Galactic passage after infall.

Idioma originalEnglish
Número de artículoA46
PublicaciónAstronomy and Astrophysics
Volumen605
DOI
EstadoPublished - 1 sep 2017

Huella dactilar

dwarf galaxies
metallicity
stars
nuclei
iron
chemical evolution
stripping
globular clusters
titanium
spectrographs
magnesium
calcium
galaxies
trends
gradients
chemical
estimates

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Citar esto

Mucciarelli, A. ; Bellazzini, M. ; Ibata, R. ; Romano, D. ; Chapman, S. C. ; Monaco, L. / Chemical abundances in the nucleus of the Sagittarius dwarf spheroidal galaxy. En: Astronomy and Astrophysics. 2017 ; Vol. 605.
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abstract = "We present iron, magnesium, calcium, and titanium abundances for 235 stars in the central region of the Sagittarius dwarf spheroidal galaxy (within 9:00∼70 pc from the centre) from medium-resolution Keck/Deep Imaging Multi-Object Spectrograph spectra. All the considered stars belong to the massive globular cluster M 54 or to the central nucleus of the galaxy (Sgr, N). In particular we provide abundances for 109 stars with [Fe/H] ≥-1:0, more than doubling the available sample of spectroscopic metallicity and-elements abundance estimates for Sgr dSph stars in this metallicity regime.We find for the first time a metallicity gradient in the Sgr,N population, whose peak iron abundance goes from [Fe/H] =-0:38 for R ≤2:50 to [Fe/H] =-0:57 for 5:0 < R 9:0. On the other hand, the trends of [Mg/Fe], [Ca/Fe], and [Ti/Fe] with [Fe/H] are the same over the entire region explored by our study.We reproduce the observed chemical patterns of the Sagittarius dwarf spheroidal as a whole with a chemical evolution model which implies that a high mass progenitor (MDM = 6 1010 M) and a significant event of mass-stripping occurred a few Gyr ago, presumably starting at the first peri-Galactic passage after infall.",
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Chemical abundances in the nucleus of the Sagittarius dwarf spheroidal galaxy. / Mucciarelli, A.; Bellazzini, M.; Ibata, R.; Romano, D.; Chapman, S. C.; Monaco, L.

En: Astronomy and Astrophysics, Vol. 605, A46, 01.09.2017.

Resultado de la investigación: Article

TY - JOUR

T1 - Chemical abundances in the nucleus of the Sagittarius dwarf spheroidal galaxy∗

AU - Mucciarelli, A.

AU - Bellazzini, M.

AU - Ibata, R.

AU - Romano, D.

AU - Chapman, S. C.

AU - Monaco, L.

PY - 2017/9/1

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N2 - We present iron, magnesium, calcium, and titanium abundances for 235 stars in the central region of the Sagittarius dwarf spheroidal galaxy (within 9:00∼70 pc from the centre) from medium-resolution Keck/Deep Imaging Multi-Object Spectrograph spectra. All the considered stars belong to the massive globular cluster M 54 or to the central nucleus of the galaxy (Sgr, N). In particular we provide abundances for 109 stars with [Fe/H] ≥-1:0, more than doubling the available sample of spectroscopic metallicity and-elements abundance estimates for Sgr dSph stars in this metallicity regime.We find for the first time a metallicity gradient in the Sgr,N population, whose peak iron abundance goes from [Fe/H] =-0:38 for R ≤2:50 to [Fe/H] =-0:57 for 5:0 < R 9:0. On the other hand, the trends of [Mg/Fe], [Ca/Fe], and [Ti/Fe] with [Fe/H] are the same over the entire region explored by our study.We reproduce the observed chemical patterns of the Sagittarius dwarf spheroidal as a whole with a chemical evolution model which implies that a high mass progenitor (MDM = 6 1010 M) and a significant event of mass-stripping occurred a few Gyr ago, presumably starting at the first peri-Galactic passage after infall.

AB - We present iron, magnesium, calcium, and titanium abundances for 235 stars in the central region of the Sagittarius dwarf spheroidal galaxy (within 9:00∼70 pc from the centre) from medium-resolution Keck/Deep Imaging Multi-Object Spectrograph spectra. All the considered stars belong to the massive globular cluster M 54 or to the central nucleus of the galaxy (Sgr, N). In particular we provide abundances for 109 stars with [Fe/H] ≥-1:0, more than doubling the available sample of spectroscopic metallicity and-elements abundance estimates for Sgr dSph stars in this metallicity regime.We find for the first time a metallicity gradient in the Sgr,N population, whose peak iron abundance goes from [Fe/H] =-0:38 for R ≤2:50 to [Fe/H] =-0:57 for 5:0 < R 9:0. On the other hand, the trends of [Mg/Fe], [Ca/Fe], and [Ti/Fe] with [Fe/H] are the same over the entire region explored by our study.We reproduce the observed chemical patterns of the Sagittarius dwarf spheroidal as a whole with a chemical evolution model which implies that a high mass progenitor (MDM = 6 1010 M) and a significant event of mass-stripping occurred a few Gyr ago, presumably starting at the first peri-Galactic passage after infall.

KW - Galaxies: Dwarf

KW - Galaxies: Stellar content

KW - Local Group

KW - Stars: Abundances

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