Maren Hempel

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  • Maren Hempel, Markus Kissler-Patig, +5 authors Stephen E.Zepf
  • 2002
Visual and near-infrared colours are used to identify intermediate-age globular cluster in early-type galaxies. In NGC 5846 and NGC 4365 colour-colour diagrams (V-I vs. V-K) reveal a sub-population in the globular cluster systems with an age much younger than the expected old populations (13-15 Gyr). A comparison with SSP models dates the formation of this(More)
An analysis of ages, metallicities, and [α/Fe] ratios of globular cluster systems in early-type galaxies is presented, based on Lick index measurements summarized in Puzia et al. (2004, Paper I of this series). In the light of calibration and measurement uncertainties, age-metallicity degeneracy, and the relative dynamic range of Lick indices, as well as(More)
We use observations from the Hubble Space Telescope Advanced Camera for Surveys (HST/ACS) study of Galactic globular clusters to investigate the spatial distribution of the inner regions of the disrupting Sagittarius dwarf spheroidal galaxy (Sgr). We combine previously published analyses of four Sgr member clusters located near or in the Sgr core (M54, Arp(More)
In this third paper of our series on near-IR and optical photometry of globular cluster systems in early-type galaxies we concentrate on the photometric results for NGC 5846 and NGC 7192, two group ellipticals, and on a first comparison between the globular cluster systems investigated so far. In NGC 5846 the colour-colour diagram shows clear bi-modality in(More)
In previous papers of the series, we used a combination of optical and near-infrared colours to derive constrains on the relative age structure in globular cluster systems. Here, we present the details, strength and limitations of our method based on Monte-Carlo simulations of colour-colour diagrams and cumulative age distributions. The simulations are(More)
We compare three different statistical models for the equation of state (EOS) of stellar matter at subnuclear densities and temperatures (0.5-10 MeV) expected to Present address: Institute for Theoretical Physics, J.W. Goethe-Universität, Max-von-Laue-Straße 1, 60438 Frankfurt am Main, Germany
We present new Hubble Space Telescope (HST)-NIC3, near-infrared H-band photometry of globular clusters (GC) around NGC 4365 and NGC 1399 in combination with archival HST-WCPC2 and ACS optical data. We find that NGC 4365 has a number of globular clusters with bluer optical colors than expected for their red optical to near-infrared colors and an old age. The(More)