New VLT observations of He I* absorbers yield a primordial ³He/⁴He ratio of (1.15^{+0.24}_{-0.21})×10^{-4} consistent with standard Big Bang nucleosynthesis, plus an updated stellar yield scaling factor.
Origin of the colour-magnitude relation of elliptical galaxies
2 Pith papers cite this work. Polarity classification is still indexing.
abstract
Evolutionary models of elliptical galaxies are constructed by using a new population synthesis code. Model parameters are calibrated to reproduce the observed colour-magnitude (CM) relation of Coma ellipticals in $V-K$ vs. $M_{V}$ diagram. The SEDs are degenerated in stellar age and metallicity. An attempt is performed to break this degeneracy, by simulating evolution of the CM relation of elliptical galaxies, based on the two alternative interpretations; i.e., the CM relation reflects different mean stellar age or various stellar metallicity. A confrontation with the CM diagrams of E/S0 galaxies in the two distant clusters Abell 2390 ($z=0.228$) and Abell 851 ($z=0.407$) reinsures previous contentions that the CM relation is primarily a metallicity effect. This conclusion does not depend either on the model parameters, or on the cosmological parameters adopted.
representative citing papers
Revised solar photospheric abundances yield Z/X = 0.0187 with C, N, O at 8.46, 7.83, 8.69, preserving the solar modeling discrepancy and revealing a modest volatile-refractory offset from CI chondrites.
citing papers explorer
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Towards a measurement of the primordial helium isotope ratio
New VLT observations of He I* absorbers yield a primordial ³He/⁴He ratio of (1.15^{+0.24}_{-0.21})×10^{-4} consistent with standard Big Bang nucleosynthesis, plus an updated stellar yield scaling factor.
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The chemical make-up of the Sun: A 2020 vision
Revised solar photospheric abundances yield Z/X = 0.0187 with C, N, O at 8.46, 7.83, 8.69, preserving the solar modeling discrepancy and revealing a modest volatile-refractory offset from CI chondrites.