We perform integrated spectroscopy of 24 Galactic globular clusters (GGCs). Spectra are observed from one core radius for each cluster with a high wavelength resolution of ∼2.0 Å FWHM. In combination with two existing data sets from Puzia et al. and Schiavon et al., we construct a large database of Lick spectral indices for a total of 53 GGCs with

We report on the discovery of a fourth component in the HD 221356 star system, previously known to be formed by an F8V, a slightly metal poor primary ([Fe/H] = -0.26), and a distant M8V+L3V pair. In our ongoing common proper motion search based on Visible and Infrared Survey Telescope for Astronomy (VISTA) Hemisphere Survey (VHS) and Two Micron All

Stellar population synthesis models are crucial for the understanding of the large amount of data which is being gathered for galaxies at low and high redshift, and provide the only way to compare the ``real world'' with the theoretical framework. The best models require extensive empirical stellar spectral libraries, which at present are starting

Iterative schemes based on Gauss-Seidel (G-S) and optimal successive over-relaxation (SOR) iteration are shown to provide a dramatic increase in the speed with which non-LTE radiation transfer (RT) problems can be solved. The convergence rates of these new RT methods are identical to those of upper triangular nonlocal approximate operator splitting

The observational picture of the enigmatic O-type spectrum variable HD 191612 has been sharpened substantially. A symmetrical, low-amplitude light curve with a period near 540 days has recently been reported from Hipparcos photometry. This period satisfies all of the spectroscopy since at least 1982, including extensive new observations during 2003

We present a catalogue of previously unpublished optical and infrared photometry for a sample of 162 emission-line objects and shell stars visible from the southern hemisphere. The data were obtained between 1978 and 1997 in the Walraven (WULBV), Johnson/Cousins (UBV(RI)c) and ESO and SAAO near-infrared (JHKLM) photometric systems. Most of the