Related papers: A new method to determine Globular Cluster ages
Globular cluster age estimates based on the absolute magnitude of the main sequence turn-off (\mvto) are generally considered to be the most reliable from a theoretical viewpoint. However, the difficulty in determining \mvto\ in observed…
We present a statistical approach for determining the age of Globular Clusters (GCs) that allows estimating the age derived from CMDs more accurately than the conventional methods of the isochrone fitting. We measure how closely a set of…
Stromgren uvby CCD photometry can be used in a variety of ways to constrain the absolute and relative ages of globular clusters. The reddening corrected (v-y, c1) diagram offers the means to derive ages that are completely independent of…
We extend our previous method to determine globular cluster ages using the luminosity function (Jimenez \& Padoan 1996). We show that the luminosity function depends on both age and distance modulus and that it is possible to distinguish…
We present a statistical approach for estimating the age of Globular Clusters by measurement of the likelihood between the observed cluster sequences in the Colour--Magnitude Diagram and the synthetic cluster sequences computed from stellar…
We present new age and distance determinations for the Galactic Globular Clusters M55 and M5, using the luminosity function method (Jimenez & Padoan 1996, Padoan & Jimenez 1997). We find an age of $11.8 \pm 1.5$ Gyr for M55 and $11.1 \pm…
In the past 40 years a considerable effort has been focused in determining the age of the Universe at zero redshift using several stellar clocks. In this review I will describe the best theoretical methods to determine the age of the oldest…
The main sequence turnoff luminosity is the best stellar `clock' which can be used to determine the absolute ages of globular clusters. This is due to the fact that it is generally assumed that the luminosity and lifetimes of main sequence…
Globular clusters are the oldest conglomerates of stars in our Galaxy and can be useful laboratories to test theories from stellar evolution to cosmology. In this paper, we present a new method to estimate the absolute age of a globular…
We present an estimate of the absolute age of 68 galactic globular clusters obtained by exploiting the distribution of stars in the full color-magnitude diagram. In particular, we jointly estimate the absolute age, distance, reddening,…
Various methods for age dating globular clusters in ellipticals are presented. We first present spectroscopy of individual globular clusters (feasible with the advent of the 10m-class telescopes), and the measurement of Balmer line indices.…
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…
Globular clusters (GCs) provide statistically significant coeval populations of stars spanning various evolutionary stages, allowing robust constraints on stellar evolution model parameters and ages. We analyze eight old Milky Way GCs with…
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…
The dominant systematic uncertainty in the age determination of galactic globular clusters is the depth of the convection envelope of the stars. This parameter is partially degenerate with metallicity which is in turn degenerate with age.…
Ages have been derived for 55 globular clusters (GCs) from overlays of isochrones onto the turnoff photometry, assuming distances based on fits of zero-age horizontal branch (ZAHB) models to the lower bound of the observed distributions of…
I review here recent developments which have affected our understanding of both the absolute age of globular clusters and the uncertainties in this age estimate, and comment on the implications for cosmological models. This present estimate…
Globular Clusters (GCs) in the Milky Way are the primary laboratories for establishing the ages of the oldest stellar populations and for measuring the color-magnitude relation of stars. In infrared (IR) color-magnitude diagrams (CMDs), the…
The age of three of the oldest clusters -- M15, M68, M92 -- has been redetermined. We use the latest EOS and opacity data available for calculating both isochrones and zero age horizontal branches and employ the brightness difference…
We present our new, fully-automated method to detect and measure the ages of star clusters in nearby galaxies, where individual stars can be resolved. The method relies purely on statistical analysis of observations and Monte-Carlo…