相关论文: Intermediate age stars as origin of the low veloci…

We derive ages, metallicities and [alpha/Fe] ratios from the integrated spectra of 23 globular clusters in M31, by employing multivariate fits to two stellar population models. In parallel we analyze spectra of 21 Galactic globular clusters…

The study of the inner region of the Milky Way's bulge is hampered by high interstellar extinction and extreme source crowding. Sensitive high angular resolution near-infrared imaging is needed to study stellar populations in such a complex…

We report the first star formation history study of the Milky Way's nuclear star cluster (NSC) that includes observational constraints from a large sample of stellar metallicity measurements. These metallicity measurements were obtained…

We have obtained near-infrared images and spectra of three blue compact dwarf galaxies of intermediate sub-solar metallicity Tol~35, Tol~3 and UM 462. This work is part of a larger project aimed to study the star formation and the stellar…

We have investigated the properties of a volume and magnitude limited sample of nearby early type galaxies that were carefully selected from the AAO two degree field galaxy redshift survey. We used images from the DSS to confirm the E/S0…

We investigated the properties of the stellar populations in the discs of a sample of ten spiral galaxies. Our analysis focused on the galaxy region where the disc contributes more than 95 per cent of total surface brightness in order to…

Effectively finding and identifying active galactic nuclei (AGNs) in dwarf galaxies is an important step in studying black hole formation and evolution. In this work, we examine four mid-IR-selected AGN candidates in dwarf galaxies with…

We present high-resolution near-infrared imaging obtained using adaptive optics and HST/NICMOS, and ground-based spectroscopy of the hot-spot galaxy NGC2903. Our near-infrared resolution imaging enables us to resolve the infrared hot spots…

We present near-infrared (H- and K-band) integral-field observations of the circumnuclear star formation rings in five nearby spiral galaxies. The data, obtained at the Very Large Telescope with the SINFONI spectrograph, are used to…

We make use of Spitzer imaging between 4 and 16 micron and near-infrared data at 2.2 micron to investigate the nature and distribution of the mid-infrared emission in a sample of early-type galaxies in the Virgo cluster. These data allow us…

The early evolution during massive star cluster formation is still uncertain. Observing embedded clusters at their earliest stages of formation can provide insight into the spatial and temporal distribution of the stars and thus probe…

Deep g'r'i'z' images obtained with the Gemini Multi-Object Spectrograph are used to investigate the stellar content in the outer regions of the nearby Sc galaxies NGC 2403 and M33. The red giant branch tip occurs at i' = 23.6 +/- 0.1 in NGC…

We present new near-infrared spectroscopic observations of the outer edges of the young stellar cluster around the supermassive black hole at the Galactic center. The observations show a break in the surface-density profile of young stars…

We present a new (V,B-V) Color-Magnitude Diagram (CMD) of the Carina dwarf spheroidal (dSph) that extends from the tip of the Red Giant Branch (RGB) down to about V=25 mag. Data were collected with the Wide Field Imager (WFI) available at…

Visual and near-infrared colours are used to identify intermediate-age globular cluster in early-type galaxies. In NGC5846 and NGC4365 colour-colour diagrams (V-I vs. V-K) reveal a sub-population in the globular cluster systems with an age…

We present a detailed spatial analysis of stellar populations based on long-slit optical spectra in a sample of eight luminous early-type galaxies selected from nearby sparse groups and pairs, three of them may be interacting with a galaxy…

We present results of an infrared study of the molecular cloud Lynds 1340, forming three groups of low and intermediate-mass stars. Our goals are to identify and characterise the young stellar population of the cloud, study the…

The supermassive black hole candidate at the Galactic Center is surrounded by a parsec-scale star cluster, which contains a number of early type stars. The presence of such stars has been called a "paradox of youth" as star formation in the…

Mid-infrared observations of the Andromeda galaxy, M31, obtained with the Infrared Array Camera on board the Spitzer Space Telescope, are presented. The image mosaics cover areas of approximate 3.7deg x 1.6deg and include the satellite…

The center of our galaxy is home to a massive black hole, SgrA*, and a nuclear star cluster containing stellar populations of various ages. While the late type stars may be too old to have retained memory of their initial orbital…