منابع مشابه
Relative Ages of Globular Clusters
Ages of extragalactic globular clusters can provide valuable insights into the formation and evolution of galaxies. In this contribution the photometric methods of age dating old globular cluster systems are summarised. The spectroscopic approach is reviewed with an emphasis of the right choice of age diagnostics. We present a new method of quantifying the relatively best age-sensitive spectros...
متن کاملThe relative ages of LMC old clusters , and the case of NGC 1841
Using archival HST/WFPC2 imaging of 7 LMC globular clusters, and following the methods outlined in our previous study, we have reached the tightest constrain so far on their age dispersion, which cannot be greater than ≈ 0.5 Gyr. We also confirm earlier results that their average age is comparable to that of the metal-poor Galactic globulars. Evidence is also provided that NGC 1841 is younger t...
متن کاملThe Relative Ages of Galactic Globular Clusters
We present a review of the present state of knowledge regarding the relative ages of Galactic globular clusters. First, we discuss the relevant galaxy formation models and describe the detailed predictions they make with respect to the formation timescale and chemical evolution of the globular clusters. Next, the techniques used to estimate globular cluster ages are described and evaluated with...
متن کاملAges of globular clusters: a new approach
We have applied a new method to analyze the horizontal branch (HB) morphology in relation to the distribution of stars near the red giant branch (RGB) tip for the globular clusters M22, M5, M68, M107, M72, M92, M3 and 47 Tuc. This new method permits determination of the cluster ages to greater accuracy than conventional isochrone fitting. Using the method in conjunction with our new high-qualit...
متن کاملExtragalactic Globular Clusters: Old Spectroscopic Ages and New Views on Their Formation
We present the results of a meta-analysis of Keck spectra of extragalactic globular clusters (GCs) in a sample of eight galaxies, ranging from dwarfs to massive ellipticals. We infer ages for the metal-poor and metal-rich GCs in these galaxies through comparisons to Galactic GCs. Both subpopulations appear to be no younger than their Galactic counterparts, with ages & 10 Gyr. This is the larges...
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ژورنال
عنوان ژورنال: The Astronomical Journal
سال: 1964
ISSN: 0004-6256
DOI: 10.1086/109420