J/A+A/605/A46 Sgr dSph nucleus stars chemical abundances (Mucciarelli+, 2017)
Chemical abundances in the nucleus of the Sagittarius dwarf spheroidal galaxy.
Mucciarelli A., Bellazzini M., Ibata R., Romano D., Chapman S.C., Monaco L.
<Astron. Astrophys. 605, A46 (2017)>
=2017A&A...605A..46M 2017A&A...605A..46M (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, spectra ; Stars, population II ; Abundances
Keywords: galaxies: dwarf - galaxies: Local Group - galaxies: stellar content -
stars: abundances
Abstract:
We present Iron, Magnesium, Calcium, and Titanium abundances for 235
stars in the central region of the Sagittarius dwarf spheroidal galaxy
(within 9.0'~=70pc from the center) from medium-resolution Keck/DEIMOS
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
α-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≤2.5' to [Fe/H]=-0.57 for 5.0<R≤9.0 arcmin. 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 implying a high mass
progenitor (MDM=6x1010M☉) and a significant event of
mass-stripping occurred a few Gyr ago, presumably starting at the
first peri-Galactic passage after infall.
Description:
Abundance ratios for iron, magnesium, calcium and titanium of 235
giant stars in the central region of the Sagittarius dwarf spheroidal
galaxy. Coordinates and atmospheric parameters (effective temperature,
surface gravities and microturbulent velocities) are provided.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 117 235 Atmospheric parameters and abundance ratios
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See also:
J/A+A/459/777 : X-ray sources in Sagittarius & Carina dSph (Cignoni+, 2006)
J/A+A/465/815 : Abundances of Sgr dSph stars (Sbordone+, 2007)
J/A+A/513/A62 : Sgr dSph VIMOS photometry & RV (Giuffrida+, 2010)
J/A+A/520/A95 : M54 and Sgr dSph red giants abundances (Carretta+, 2010)
J/ApJ/756/74 : 2MASS view of Sgr dSph. VII. Kinematics (Frinchaboy+, 2012)
J/AJ/145/163 : Catalog of stars in Sgr dwarf galaxy (Newby+, 2013)
J/MNRAS/444/1812 : M54 red giants abundances (Mucciarelli+, 2014)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 7 I7 --- ID [1500190/4210645] Identification number
11- 20 F10.6 deg RAdeg Right ascension (J2000)
24- 33 F10.6 deg DEdeg Declination (J2000)
37- 40 I4 K Teff Effective temperature
44- 47 F4.2 [cm/s2] log(g) Surface gravity
51- 53 F3.1 km/s vt Microturbulent velocity
57- 61 F5.2 [Sun] [Fe/H] Relative abundance [Fe/H]
66- 69 F4.2 [Sun] e_[Fe/H] Uncertainty on [Fe/H]
73- 77 F5.2 [Sun] [Mg/Fe] ?=99.99 Relative abundance [Mg/Fe]
82- 85 F4.2 [Sun] e_[Mg/Fe] ?=0 Uncertainty on [Mg/Fe]
89- 93 F5.2 [Sun] [Ca/Fe] Relative abundance [Ca/Fe]
98-101 F4.2 [Sun] e_[Ca/Fe] Uncertainty on [Ca/Fe]
105-109 F5.2 [Sun] [Ti/Fe] ?=99.99 Relative abundance [Ti/Fe]
114-117 F4.2 [Sun] e_[Ti/Fe] ?=0 Uncertainty on [Ti/Fe]
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Acknowledgements:
Alessio Mucciarelli, alessio.mucciarelli2(at)unibo.it
(End) Patricia Vannier [CDS] 19-May-2017