相关论文: The multiple stellar population in omega Centauri:…

We study dwarf galaxies in the Centaurus A group to investigate their metallicity and possible environmental effects. The Centaurus A group (at ~4 Mpc from the Milky Way) contains about 50 known dwarf companions of different morphologies…

We present HST observations that show a bifurcation of colors in the middle main sequence of the globular cluster Omega Centauri. We see this in three different fields, observed with different cameras and filters. We also present high…

We focus on two aspects of Omega Cen that are rather uncharacteristic of globular clusters: its metallicity distribution and its orbit. We use (1) a Washington (M-T_2,M)_o color-magnitude diagram containing 130,000 stars, (2) DDO51…

The nature and formation history of our Galaxy's largest and most enigmatic stellar cluster, known as Omega Centauri (ocen) remains debated. Here, we offer a novel approach to disentangling the complex stellar populations within ocen based…

Updated data of the 153 Galactic globular clusters are used to readdress fundamental parameters of the Milky Way. We build a reduced sample, decontaminated of the clusters younger than 10Gyr, those with retrograde orbits and/or evidence of…

For the first time, the abundances of a large sample of subgiant and turn-off region stars in omega Centauri have been measured, the data base being medium resolution spectroscopy from FORS2 at the VLT. Absolute iron abundances were derived…

The inner Galactic Bulge has, until recently, been avoided in chemical evolution studies due to extreme extinction and stellar crowding. Large, near-IR spectroscopic surveys, such as APOGEE, allow for the first time the measurement of…

(Abriged) We report results of a campaign to image the stellar populations in the halos of highly inclined spiral galaxies, with the fields roughly 10 kpc (projected) from the nuclei. We use the F814W (I) and F606W (V) filters in the Wide…

In our previous study, we showed that the peculiar globular cluster (GC) M22 contains two distinct stellar populations, namely the Ca-w and Ca-s groups with different physical properties, having different chemical compositions, spatial…

An understanding of the assembly history of the complex star cluster Omega Centauri has long been sought after, with many studies separating the stars on the color-magnitude diagram into multiple groupings across small magnitude ranges.…

We have measured central line strengths for a magnitude-limited sample of early-type galaxies in the Fornax cluster, comprising 11 elliptical (E) and 11 lenticular (S0) galaxies, more luminous than MB=-17. When compared with single-burst…

The halo and disc globular cluster population can be used as a tracer of the primordial epochs of the Milky Way formation. In this work, literature data of globular clusters ages, chemical abundances, and structural parameters are studied,…

We present manganese abundances in 10 red-giant members of the globular cluster Omega Centauri; 8 stars are from the most metal-poor population (RGB MP and RGB MInt1) while two targets are members of the more metal rich groups (RGB MInt2…

The existence of complex stellar populations in some star clusters challenges the understanding of star formation. E.g. the ONC or the sigma Orionis cluster host much older stars than the main bulk of the young stars. Massive star clusters…

Knowing the metallicity distribution of stars in the Galactic Centre has important implications for the formation history of the Milky Way nuclear star cluster. However, this distribution is not well known, and is currently based on a small…

The most massive elliptical galaxies show a prominent multi-modality in their globular cluster system color distributions. Understanding the mechanisms which lead to multiple globular cluster sub-populations is essential for a complete…

We present new intermediate-band Stroemgren photometry based on more than 300 u,v,b,y images of the Galactic globular cluster Omega Cen. Optical data were supplemented with new multiband near-infrared (NIR) photometry (350 J,H,K_s images).…

We compute the spatial velocity components and the galactic orbital elements for 209 metal-poor $([Fe/H] < -1.0)$ RRLyrae (ab) variable stars in the solar neighborhood using proper motions, radial velocities, and photometric distances…

Wide-field and deep DECam multi-band photometry, combined with HST data for the core of the Galactic globular cluster NGC 2808, allowed us to study the distribution of various stellar sub-populations and stars in different evolutionary…

We present a near-infrared J and K photometric catalog containing more than 73,000 stars in the central region of the giant Globular Cluster omega Centauri. This is the largest IR data-set ever published for this cluster and has been used…