Related papers: 47 Tuc: The Spectroscopic Versus CMD Age Discrepan…

By means of a semi-analytic model of galaxy formation, we show how the local observed relation between age and galactic stellar mass is affected by assuming a DM power spectrum with a small-scale cutoff. We compare results obtained by means…

Using a widely used stellar population synthesis model, we study the ability of using pairs of AB system colours to break the well-known stellar age--metallicity degeneracy and give constraints on the two stellar-population parameters (age…

We establish a framework for determing absolute ages of Galactic globular clusters and then use these ages to investigate the age-metallicity and age-Galactocentric distance relations for the 36 clusters with the most reliable age data. The…

Galaxy interactions are known to trigger starbursts. The young star clusters formed in mergers may be young globular clusters. The ages of these young star clusters yield the timing of interaction-triggered star formation and provide an…

We present the first results of a large ACS Survey of Galactic globular clusters. This Hubble Space Telescope (HST) Treasury project is designed to obtain photometry with S/N > ~10 for main sequence stars with masses > ~0.2Msun in a sample…

We present new B, V and I-band photometry for a sample of 43 local subdwarfs with HIPPARCOS parallax errors < 13%, in the metallicity range -1.0 < [Fe/H] < -0.3, which we use to perform main sequence (MS) fitting to the Galactic globular…

Recent studies have shown that an extended main-sequence turn-off is a common feature among intermediate-age clusters (1--3 Gyr) in the Magellanic Clouds. Multiple-generation star formation and stellar rotation or interacting binaries have…

Context:Ages derived from the low mass stars still contracting onto the main sequence often differ from ages derived from the high mass ones that have already evolved away from it. Aims:We investigate the general claim of disagreement…

The LMC has a rich star cluster system spanning a wide range of ages and masses. One striking feature of the LMC cluster system is the existence of an age gap between 3-10 Gyrs. Four LMC clusters whose integrated colours are consistent with…

We study 147 star clusters in the Large Magellanic Cloud (LMC) in order to determine their mean metallicities and ages, as well as the mean metallicities of 80 surrounding fields. We construct an age-metallicity relation (AMR) for the…

We determine the relative ages of the open cluster NGC 188 and selected Hipparcos field stars by isochrone fitting, and compare them to the age of the thick disk globular cluster 47 Tuc. The best fit age for NGC 188 was determined to be…

There is growing evidence that star clusters can no longer be considered simple stellar populations (SSPs). Intermediate and old age clusters are often found to have extended main sequence turn-offs (eMSTOs) which are difficult to explain…

Previously [Y/Mg] has been proven to be an age indicator for solar twins. Here, we investigate if this relation also holds for helium-core-burning stars of solar metallicity. High resolution and high signal-to-noise ratio (S/N)…

We present the results of photometric measurements from images of the LMC cluster ESO 121-SC03 taken with HST/ACS. Our resulting CMD reaches 3 magnitudes below the main-sequence turn-off, representing the deepest observation of this cluster…

We present the results of a long term orbit monitoring program, using sparse aperture masking observations taken with NIRC2 on the Keck-II telescope, of seven G to M-type members of the Upper Scorpius subgroup of the Sco-Cen OB association.…

The star cluster (SC) age distribution of the Large Magellanic Cloud (LMC) exhibits a gap from $\sim$ 4 to 10 Gyr ago, with an almost total absence of SCs. Within this age gap, only two confirmed SCs have been identified hitherto.…

We present aluminium abundances for a sample of about 100 red giant stars in each of the Galactic globular clusters 47 Tuc (NGC 104) and M 4 (NGC 6121). We have derived homogeneous abundances from intermediate-resolution FLAMES/GIRAFFE…

We present a comprehensive analysis of the ability of current stellar population models to reproduce the optical (ugriz) and near infra-red (JHK) colours of a small sample of well-studied nearby elliptical and S0 galaxies. We find broad…

A major uncertainty in the spectroscopic dating of extragalactic globular clusters concerns the degenerate effect that age and horizontal branch morphology have on the strength of Balmer lines. In this Letter we show that the ratio between…

Integrated spectra have been obtained of 31 star clusters in the Magellanic Clouds (MC) and of 4 Galactic globular clusters. The spectra cover the wavelength range 3500 -- 4700 Angstroms at a resolution of 3.2 Angstroms FWHM. The MC…