Results 51 to 60 of about 206,370 (204)

Nebular Abundances of Nearby Southern Dwarf Galaxies [PDF]

open access: yesAstron.Astrophys. 401 (2003) 141, 2003
The results of optical spectroscopy of H II regions in a sample of southern dwarf irregulars consisting of five dwarf galaxies in the Centaurus A group, four dwarfs in the Sculptor group, and eight additional dwarf galaxies are presented. Oxygen abundances are derived using the direct method where [O III]4363 is detected; otherwise, abundances are ...
arxiv   +1 more source

Oxygen and nitrogen abundances in Virgo and field spirals [PDF]

open access: yes, 2001
The oxygen and nitrogen abundances in the HII regions of the nine Virgo spirals of the sample from Skillman et al (1996) and in nine field spiral galaxies are re-determined with the recently suggested P - method.
Alloin   +79 more
core   +2 more sources

The Gas-phase Mass–Metallicity Relation for Massive Galaxies at z ∼ 0.7 with the LEGA-C Survey

open access: yesThe Astrophysical Journal
The massive end of the gas-phase mass–metallicity relation (MZR) is a sensitive probe of active galactic nuclei (AGN) feedback that is a crucial but highly uncertain component of galaxy evolution models.
Zach J. Lewis   +14 more
doaj   +1 more source

Chemical Abundances of the Leo II Dwarf Galaxy

open access: yes, 2008
We use previously-published moderate-resolution spectra in combination with stellar atmosphere models to derive the first measured chemical abundance ratios in the Leo II dSph galaxy.
Azzopardi   +44 more
core   +1 more source

The Heavy Metal Survey: The Evolution of Stellar Metallicities, Abundance Ratios, and Ages of Massive Quiescent Galaxies since z ∼ 2

open access: yesThe Astrophysical Journal
We present the elemental abundances and ages of 19 massive quiescent galaxies at z ∼ 1.4 and z ∼ 2.1 from the Keck Heavy Metal Survey. The ultradeep LRIS and MOSFIRE spectra were modeled using a full-spectrum stellar population fitting code with variable
Aliza G. Beverage   +13 more
doaj   +1 more source

The Distribution of Alpha Elements in Andromeda Dwarf Galaxies [PDF]

open access: yes, 2014
We present alpha to iron abundance ratios for 226 individual red giant branch stars in nine dwarf galaxies of the Andromeda (M 31) satellite system. The abundances are measured from the combined signal of Mg, Si, Ca, and Ti lines in Keck/DEIMOS medium-resolution spectra.
arxiv   +1 more source

The building up of the disk galaxy M33 and the evolution of the metallicity gradient

open access: yes, 2007
The evolution of radial gradients of metallicity in disk galaxies and its relation with the disk formation are not well understood. Theoretical models of galactic chemical evolution make contrasting predictions about the time evolution of metallicity ...
Aller   +104 more
core   +1 more source

Chemical Abundance Analysis of Tucana III, the Second $r$-process Enhanced Ultra-Faint Dwarf Galaxy [PDF]

open access: yes, 2019
We present a chemical abundance analysis of four additional confirmed member stars of Tucana III, a Milky Way satellite galaxy candidate in the process of being tidally disrupted as it is accreted by the Galaxy.
Bechtol, K.   +60 more
core   +3 more sources

Barium abundance in the central part of the dSph Fornax galaxy [PDF]

open access: yes, 2017
We revisited barium abundance in a sample of giant stars in the dwarf spheroidal Fornax galaxy. Non-local thermodynamic equilibrium (NLTE) synthesis was used to derive the barium abundance from two Ba II lines. Our new NLTE result for barium shows that in the range of metallicities from -1 to -0.5 the abundance of this element is almost the same as in ...
arxiv   +1 more source

Nucleosynthesis: Stellar and Solar Abundances and Atomic Data [PDF]

open access: yes, 2006
Abundance observations indicate the presence of often surprisingly large amounts of neutron capture (i.e., s- and r-process) elements in old Galactic halo and globular cluster stars.
Collier, Jason   +5 more
core   +4 more sources

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