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The color distributions of globular clusters (GCs) in individual early-type galaxies show great diversity in their morphology. Based on the conventional "linear" relationship between the colors and metallicities of GCs, the GC metallicity…

Astrophysics of Galaxies · Physics 2019-01-09 Sang-Yoon Lee , Chul Chung , Suk-Jin Yoon

Globular clusters are the oldest stellar systems in the Milky Way and probe the early epoch of the Galaxy formation. However, the uncertainties on their absolute age are still too large to soundly constrain how the Galactic structures have…

Astrophysics of Galaxies · Physics 2016-01-27 Davide Massari , G. Fiorentino , A. McConnachie , G. Bono , M. Dall'Ora , I. Ferraro , G. Iannicola , P. B. Stetson , P. Turri , E. Tolstoy

We present homogeneous scales of ages and metallicities for star clusters from very young objects, through intermediate-age ones up to the oldest known clusters. All the selected clusters have integrated spectra in the visible range, as…

Astrophysics · Physics 2009-11-10 J. F. C. Santos , A. E. Piatti

A subset of 150 globular clusters in M87 has been selected on the basis of S/N ratio for abundance and age determinations from the sample of Paper I. Indices measuring the strength of the strongest spectral features were determined for the…

Astrophysics · Physics 2009-10-30 Judith G. Cohen , John P. Blakeslee , Anton Ryzhov

Reconstructing the mass assembly history of the Milky Way relies on obtaining detailed measurements of the properties of many stars in the Galaxy, especially in the stellar halo. One of the most constraining quantities is stellar age, as it…

Astrophysics of Galaxies · Physics 2024-06-11 Danny Horta , Yuxi , Lu , Melissa K. Ness , Mariangela Lisanti , Adrian M. Price-Whelan

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…

Astrophysics · Physics 2007-05-23 Ivo Saviane , Alfred Rosenberg , Giampaolo Piotto , Antonio Aparicio

We present a new technique to determine age and metallicity of old stellar populations (globular clusters and elliptical galaxies) using an iterative principal component analysis on narrow band (Str\"omgren) colors. Our technique is capable…

Astrophysics · Physics 2009-11-11 K. Rakos , J. Schombert , A. Odell

Omega Centauri is a peculiar Globular Cluster formed by a complex stellar population. To shed light on this, we studied 172 stars belonging to the 5 SGBs that we can identify in our photometry, in order to measure their [Fe/H] content as…

Astrophysics of Galaxies · Physics 2015-06-22 S. Villanova , D. Geisler , R. G. Gratton , S. Cassisi

Hickson Compact Groups (HCGs) constitute an interesting extreme in the range of environments in which galaxies are located, as the space density of galaxies in these small groups are otherwise only found in the centres of much larger…

We present an analysis of the positions and ages of young star clusters in eight local galaxies to investigate the connection between the age difference and separation of cluster pairs. We find that star clusters do not form uniformly but…

The vertical metallicity gradient of the Galactic disk offers valuable insights into the disk's formation and chemical evolution over time. We utilized the LAMOST-LRS young stellar sample to investigate this gradient and found that it…

Astrophysics of Galaxies · Physics 2025-04-03 Gaohuan Long , Haibo Yuan , Shuai Xu , Chun Wang , Ruoyi Zhang , Bowen Huang

We report results that show that the straightforwardly star cluster metallicities obtained from Str\"omgren $vby$ photometry is age-dependent and need to be corrected for further use. This outcome arises from the comparison of [Fe/H] values…

Astrophysics of Galaxies · Physics 2020-10-14 Andrés E. Piatti

The main goal of our project is to obtain a complete picture of individual open clusters from homogeneous data and then search for correlations between their astrophysical parameters. The near-infrared JHKS photometric data from the…

Solar and Stellar Astrophysics · Physics 2011-07-27 Ł. Bukowiecki , G. Maciejewski , P. Konorski , A. Strobel

We present a spectroscopic analysis of the metallicities, ages, and alpha-elements of the globular clusters (GCs) in the giant elliptical galaxy (gE) NGC 4636 in the Virgo cluster. Line indices of the GCs are measured from the integrated…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 Hong Soo Park , Myung Gyoon Lee , Ho Seong Hwang , Sang Chul Kim , Nobuo Arimoto , Yoshihiko Yamada , Naoyuki Tamura , Masato Onodera

In this paper we have compiled two new open cluster catalogues. In the first one, there are 119 objects with ages, distances and metallicities available, while in the second one, 144 objects have both absolute proper motion and radial…

Astrophysics · Physics 2009-11-07 L. Chen , J. L. Hou , J. J. Wang

A set of 76 open clusters with abundances based upon DDO photometry and/or moderate dispersion spectroscopy has been transformed to a common [Fe/H] scale and used to study the local structure and evolution of the galactic disk. The…

Astrophysics · Physics 2009-10-30 Bruce A. Twarog , Keith M. Ashman , Barbara J. Anthony-Twarog

We present a new, high-resolution chronographic (age) map of the Milky Way's halo, based on the inferred ages of ~130,000 field blue horizontal-branch (BHB) stars with photometry from the Sloan Digital Sky Survey. Our map exhibits a strong…

Astrophysics of Galaxies · Physics 2016-09-08 D. Carollo , T. C. Beers , V. M. Placco , R. M. Santucci , P. Denissenkov , P. B. Tissera , G. Lentner , S. Rossi , Y. S. Lee , J. Tumlinson

In this paper, we discuss the properties of CMDs, age, metallicity and radial velocities of eight massive LMC clusters using data taken from FORS2 multiobject spectrograph at the 8.2-meter VLT/UT1. The strong near-infrared Ca II triplet…

Astrophysics of Galaxies · Physics 2015-05-14 Saurabh Sharma , J. Borissova , R. Kurtev , V. D. Ivanov , D. Geisler

This is the third article in a series aimed at computing accurate and precise ages of galactic globular clusters from their full color-magnitude diagram in order to estimate the age of the Universe and in turn constrain the cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2025-03-26 David Valcin , Raul Jimenez , Uroš Seljak , Licia Verde

The effects of the orbital diffusion of stars and clusters on the galactic abundance gradient have been modelled. For a single generation of field stars, the results confirm previous analyses based upon the assumption of a linear gradient…

Astrophysics · Physics 2009-11-06 Stuartt Corder , Bruce A. Twarog
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