Related papers: A Spectroscopic Survey for Omega Centauri Members …

We present results from 1351 high resolution spectra of 1215 stars in the Orion Nebula Cluster (ONC) and the surrounding Orion 1c association, obtained with the Hectochelle multiobject echelle spectrograph on the 6.5m MMT. We confirmed 1111…

We present a study of the white dwarf (WD) cooling sequence (CS) in the globular cluster (GC) Omega Centauri, the primary goal of a dedicated Hubble Space Telescope (HST) programme. Our analysis has revealed that the peak at the termination…

Deep images of the Centaurus and Coma clusters reveal two spectacular arcs of diffuse light that stretch for over 100 kpc, yet are just a few kpc wide. At a surface brightness of m_b \sim 27-28th arcsec^-2, the Centaurus arc is the most…

We have observed (with vby filters) a field north of the core of the most massive globular cluster in our galaxy, Omega Centauri. We have found a correlation of age and metallicity in a region which avoids the dense core and the…

Aim: To extend the investigations of ultra-compact dwarf galaxies (UCDs) beyond the well studied Fornax and Virgo clusters. Methods: We measured spectroscopic redshifts of about 400 compact object candidates with 19.2 < V < 22.4 mag in the…

We used the multiplex capabilities of the AAOmega spectrograph at the Anglo-Australian Telescope to create a half-square-degree map of the neutral and low-ionized ISM in front of the nearby (~5 kpc), most massive Galactic globular cluster,…

Omega Centauri is the most massive and chemically complex multi-population globular cluster with a wide metallicity range that has been extensively studied photometrically and spectroscopically. Using the wide metallicity range of omega…

(abbreviated) We consider how tight binaries consisting of a super-massive black hole of mass $M=10^{3}-10^{4}M_{\odot}$ and a white dwarf can be formed in a globular cluster. We point out that a major fraction of white dwarfs tidally…

The dense central regions of tidally disrupted galaxies can survive as ultra-compact dwarfs (UCDs) that hide among the luminous globular clusters (GCs) in the halo of massive galaxies. An exciting confirmation of this model is the detection…

We report on a high-spatial-resolution survey for binary stars in the periphery of the Orion Nebula Cluster, at 5 - 15 arcmin (0.65 - 2 pc) from the cluster center. We observed 228 stars with adaptive optics systems, in order to find…

We report the identification of a numerous binary star population in the recently discovered ~3 Gyr old open cluster UBC 274. It becomes visible once the cluster color-magnitude diagram is corrected by differential reddening and spans mass…

The distribution of member stars in the surroundings of an Open Cluster (OC) can shed light on the process of its formation, evolution and dissolution. The analysis of structural parameters of OCs as a function of their age and position in…

Using wide-field photometric data from the Sloan Digital Sky Survey (SDSS) we recently showed that the Galactic globular cluster Palomar 5 is in the process of being tidally disrupted. Its tidal tails were initially detected in a 2.5 degree…

We present accurate and deep multiband B,R,Halpha data for the globular cluster Omega Cen collected with the Advanced Camera for Surveys on HST. The photometric catalogue includes more than one million stars. By adopting severe selection…

Globular clusters have linear sizes (tidal radii) which theory tells us are determined by their masses and by the gravitational potential of their host galaxy. To explore the relationship between observed and expected radii, we utilize the…

We present a large multi-epoch high resolution spectroscopic investigation for the search of binary candidates in the Galactic Globular Cluster (GGC) M4. The aim of our work is the identification of the binary candidates, and the…

Context: Tidal tails of open clusters are the result of stellar evaporation from the cluster through the Galactic potential and internal dynamics. With the recent availability of high-precision data, tidal tails are being detected for most…

We carry out an imaging survey of six globular clusters (GCs) with a limit magnitude to 22 mag at the 5 sigma level, down to the main sequence stars of the respective cluster, as one of the pilot observing program of the Wide Field Survey…

Using the recently commissioned multi-object spectrograph AAOmega on the 3.9m AAT we have obtained medium-resolution near-infrared spectra for 10,500 stars in and around five southern globular clusters. The targets were 47 Tuc, M12, M30,…

We present a spectroscopic survey of the stellar population of the Sigma Orionis cluster. We have obtained spectral types for 340 stars. Spectroscopic data for spectral typing come from several spectrographs with similar spectroscopic…