We present a detailed study of the composition of 20 M giants in the Galactic center with 15 of them confirmed to be in the nuclear star cluster. As a control sample we have also observed 7 M giants in the Milky Way disk with similar stellar parameters. All 27 stars are observed using the NIRSPEC spectrograph on the KECK II telescope in the K-band

Many problems in contemporary astrophysics—from understanding the formation of black holes to untangling the chemical evolution of galaxies—rely on knowledge about binary stars. This, in turn, depends on the discovery and characterization of binary companions for large numbers of different kinds of stars in different chemical and dynamical

The galaxy-wide stellar initial mass function (gwIMF) of a galaxy in dependence on its metallicity and star formation rate can be calculated by the integrated galactic IMF (IGIMF) theory. This theory has been applied in a study of the chemical evolution of the ultra-faint dwarf (UFD) satellite galaxies, but failed to reproduce the data. Here, we

Aims: We aim to analyse our study of the X-ray transient Swift J1745-26, using observations obtained from its outburst in September 2012, up to its decay towards quiescence in March 2013. Methods: We obtained optical and infrared observations, through override programme at ESO/VLT with FORS2 and ISAAC instruments, and added archival optical (VLT

Context. AT 2019abn was discovered in the nearby M51 galaxy by the Zwicky Transient Facility at more than two magnitudes and around three weeks prior to its optical peak. Aims: We aim to conduct a detailed photometric and spectroscopic follow-up campaign for AT 2019abn, with early discovery allowing for significant pre-maximum observations of an

Near-infrared spectroscopic surveys have uncovered a population of short-period, blended-light spectral binaries composed of low-mass stars and brown dwarfs. These systems are amenable to orbit determination and individual mass measurements via astrometric monitoring. Here, we present first results of a multiyear campaign to obtain high-precision