Related papers: NGC1856: Using machine learning techniques to unco…

The LMC and SMC are rich in binary star clusters, and some mergers are expected. It is important to characterize single clusters, binary clusters and candidates to mergers. We selected a sample of star clusters in each Cloud with this aim.…

Studies of the magnetic characteristics of massive stars have recently received significant attention because they are progenitors of highly magnetised compact objects. Stars initially more massive than about 8M_sun leave behind neutron…

We present the analysis of a deep colour-magnitude diagram (CMD) of NGC 1831, a rich star cluster in the LMC. The data were obtained with HST/WFPC2 in the F555W (~V) and F814W (~I) filters, reaching m_555 ~ 25. We discuss and apply a method…

We provide a library of some 7000 SEDs (available at www.eso.org/~rsiebenm) for the nuclei of starburst and ultra luminous galaxies. Its purpose is to quickly obtain estimates of the basic parameters, such as luminosity, size and dust or…

The Magellanic Clouds are the most massive and closest satellite galaxies of the Milky Way, with stars covering ages from a few Myr up to 13 Gyr. This makes them important for validating integrated light methods to study stellar populations…

The relation between the maximum stellar mass in a very young cluster (mmax) and the total stellar mass of the cluster (Mecl), known as the mmax-Mecl relation, remains debated in the literature. To test the validity of this relation, we…

(abridged) Mass loss is a key parameter in the evolution of massive stars, with discrepancies between theory and observations and with unknown importance of the episodic mass loss. To address this we need increased numbers of classified…

MUSE, the Multi Unit Spectroscopic Explorer, is a 2nd generation integral-field spectrograph under final assembly to see first light at the Very Large Telescope in 2013. By capturing ~ 90000 optical spectra in a single exposure, MUSE…

We present the results obtained with MUSE on the core of the lensing cluster A1689. Integral-field observations with MUSE provide a unique view of the central region, allowing us to conduct a complete census on both cluster galaxies and…

Multiple populations are ubiquitous in the old massive globular clusters (GCs) of the Milky Way. It is still unclear how they arose during the formation of a GC. The topic of iron and metallicity variations has recently attracted attention…

We have used deep high-resolution Hubble Space Telescope ACS observations to image the cluster NGC 1978 in the Large Magellanic Cloud. This high-quality photometric data set allowed us to confirm the high ellipticity (~0.30+-0.02) of this…

We present an innovative and widely applicable approach for the detection and classification of stellar clusters, developed for the PHANGS-HST Treasury Program, an $NUV$-to-$I$ band imaging campaign of 38 spiral galaxies. Our pipeline first…

Traditional artificial-star tests are widely applied to photometry in crowded stellar fields. However, to obtain reliable binary fractions (and their uncertainties) of remote, dense, and rich star clusters, one needs to recover huge numbers…

Using high-resolution Hubble Space Telescope data, we reexamine the fundamental properties (ages, masses and extinction values) of the rich star cluster population in the dwarf starburst galaxy NGC 5253. The gain in resolution compared to…

Context. Efforts to look for signatures of the first stars have concentrated on metal-poor halo objects. However, the low end of the bulge metallicity distribution has been shown to host some of the oldest objects in the Milky Way and hence…

Large spectroscopic surveys of individual massive stars, such as ULLYSES and XSHOOTU, provide observational data for hundreds of massive stars. Their analysis requires large numbers of synthetic spectra so that stellar parameters can be…

We investigate stellar elemental abundance patterns at z = 0 in 8 low-mass (M_* = 10^6 - 10^9 M_sun) galaxies in the Feedback in Realistic Environments (FIRE-2) cosmological simulations. Using magnesium (Mg) as a representative…

$\omega$ Cen is a rare example of a globular cluster where the iron abundance of the stars spans more than one order of magnitude. Many spectroscopic investigations of its red-giant- and sub-giant- branches have revealed multiple peaks in…

The finding of multiple stellar populations (MP), defined by patterns in the stellar element abundances, is nowadays considered a distinctive feature of globular clusters. However, while data availability and quality improved in last…

In order to obtain morphological information of unlabeled galaxies, we present an unsupervised machine-learning (UML) method for morphological classification of galaxies, which can be summarized as two aspects: (1) the methodology of…