التفاصيل البيبلوغرافية
| العنوان: |
Chemical abundances in the nucleus of the Sagittarius dwarf spheroidal galaxy. |
| المؤلفون: |
Mucciarelli, A.1,2 alessio.mucciarelli2@unibo.it, Bellazzini, M.2, Ibata, R.3, Romano, D.2, Chapman, S. C.4, Monaco, L.5 |
| المصدر: |
Astronomy & Astrophysics / Astronomie et Astrophysique. Sep2017, Vol. 605, p1-12. 12p. |
| مصطلحات موضوعية: |
*COSMIC abundances, *SAGITTARIUS dwarf spheroidal galaxy, *SPECTROGRAPHS, *MILKY Way, LOCAL Group (Astronomy) |
| مستخلص: |
We present iron, magnesium, calcium, and titanium abundances for 235 stars in the central region of the Sagittarius dwarf spheroidal galaxy (within 9:0' ≃ 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 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'. 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. [ABSTRACT FROM AUTHOR] |
| قاعدة البيانات: |
Academic Search Index |
Full Text Finder