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Related papers: Is the galactic disk older than the halo?

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We present the analysis of the morphological shape of Berkeley 17, the oldest known open cluster (~10 Gyr), using a probabilistic star counting of Pan-STARRS point sources, and confirm its core-tail shape, plus an antitail, previously…

Solar and Stellar Astrophysics · Physics 2017-10-04 Souradeep Bhattacharya , Ishan Mishra , Kaushar Vaidya , Wen-Ping Chen

HST (V,I) photometry has been obtained for the inner halo globular cluster NGC 6652. The photometry reaches approximately 4 mag below the turn-off and includes a well populated horizontal branch. This cluster is located close to the…

Astrophysics · Physics 2009-10-31 Brian Chaboyer , Ata Sarajedini , Taft E. Armandroff

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

The number of known globular clusters in the Galactic bulge has been increasing steadily thanks to different new surveys. The aim of this study is to provide a census of the newly revealed globular clusters in the Galactic bulge, and…

Astrophysics of Galaxies · Physics 2024-08-06 E. Bica , S. Ortolani , B. Barbuy , R. A. P. Oliveira

Luminosities and tidal radii of globular clusters have been used to estimate the perigalactic distances P of well-observed Galactic globulars that do not have collapsed cores. It is found that the cluster metallicity [Fe/H] correlates…

Astrophysics · Physics 2009-10-28 Sidney van den Bergh

We report the results of a detailed numerical study designed to estimate both the absolute age and the uncertainty in age (with confidence limits) of the oldest globular clusters. Such an estimate is essential if a comparison with the…

Astrophysics · Physics 2009-10-28 Brian Chaboyer , Peter J. Kernan , Lawrence M. Krauss , Pierre Demarque

We construct mock galaxy catalogues to analyse clustering properties of a Lambda cold dark matter (LCDM) universe within a cosmological dark matter simulation of sufficient resolution to resolve structure down to the scale of dwarfs. We…

Astrophysics · Physics 2008-11-26 Darren S. Reed , Fabio Governato , Thomas Quinn , Joachim Stadel , George Lake

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

Hierarchical star formation leads to a progressive decrease in the clustering of star clusters both in terms of spatial scale and age. Consistently, the statistical analysis of positions and ages of clusters in the Milky Way disk strongly…

Astrophysics of Galaxies · Physics 2009-07-22 R. de la Fuente Marcos , C. de la Fuente Marcos

Based on an almost complete sample of Galactic open star clusters within 1.8 kpc, we perform a comprehensive statistical analysis of various cluster parameters like spatial position, age, size, mass and extinction in order to understand the…

Astrophysics of Galaxies · Physics 2016-10-18 Yogesh C. Joshi , Andrei Dambis , Anil K. Pandey , Santosh Joshi

We revisit the determination of the age of the Universe from galactic globular clusters, extending previous analyses by explicitly accounting for the presence of multiple stellar populations within each cluster. Using high--quality…

Astrophysics of Galaxies · Physics 2026-03-06 David Valcin , Raul Jimenez , Carmela Lardo , Uroš Seljak , Licia Verde

Nine presently known "young" Galactic globular clusters, which have ages / 3 Gyr smaller than the oldest clusters of similar metallicity, all have RGC > 15 kpc. Furthermore these young globulars are found to have below-average luminosities.…

Astrophysics · Physics 2009-10-30 Sidney van den Bergh

Models of stellar structure and evolution can be constrained by measuring accurate parameters of detached eclipsing binaries in open clusters. Multiple binary stars provide the means to determine helium abundances in these old stellar…

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,…

Cosmology and Nongalactic Astrophysics · Physics 2022-01-24 David Valcin , José Luis Bernal , Raul Jimenez , Licia Verde , Benjamin D. Wandelt

Context. The scale height of the spatial distribution of open clusters (OCs) in the Milky Way exhibits a well known increase with age which is usually interpreted as evidence for dynamical heating of the disc or of the disc having been…

Astrophysics of Galaxies · Physics 2025-02-05 Sandro Moreira , André Moitinho , André Silva , Duarte Almeida

We present V, V-I color-magnitude diagrams (CMDs) for three old star clusters in the Large Magellanic Cloud (LMC): NGC 1466, NGC 2257 and Hodge 11. Our data extend about 3 magnitudes below the main-sequence turnoff, allowing us to determine…

Astrophysics · Physics 2009-10-31 J. A. Johnson , M. Bolte , P. B. Stetson , J. E. Hesser , R. S. Somerville

The all-sky Milky Way Star Clusters (MWSC) survey provides uniform and precise ages and other parameters for a variety of clusters in the Solar Neighbourhood. We construct the cluster age distribution, investigate its spatial variations,…

Astrophysics of Galaxies · Physics 2018-06-13 A. E. Piskunov , A. Just , N. V. Kharchenko , P. Berczik , R. -D. Scholz , S. Reffert , S. X. Yen

The velocity dispersion of nearby stars in the Galactic disc is well known to increase substantially with age; this is the so-called Age-Velocity relation, and is interpreted as a ``heating'' of the disc as a function of time. We have…

Astrophysics · Physics 2009-11-07 Jyrki Hanninen , Chris Flynn

The determination of the age of the bulge has led to two contradictory results. On the one side, the color-magnitude diagrams in different bulge fields seem to indicate a uniformly old ($>$10 Gyr) population. On the other side, individual…

Astrophysics of Galaxies · Physics 2016-10-05 M. Haywood , P. Di Matteo , O. Snaith , A. Calamida

We present an investigation of the relationship between giant molecular cloud (GMC) properties and the associated stellar clusters in the nearby flocculent galaxy NGC 7793. We combine the star cluster catalog from the HST LEGUS (Legacy…