相关论文: A stellar stream remnant of a globular cluster bel…

Detailed studies of stellar populations in the halos of the Milky Way and the Andromeda (M 31) galaxies have shown increasing numbers of tidal streams and dwarf galaxies, attesting to a complicated and on-going process of hierarchical…

Observations of an ancient stellar stream provide the first evidence of a vanished population of extremely metal-poor stellar clusters. Their remnants might reveal how the early assembly of the Milky Way proceeded.

We present first results concerning the metallicities and stellar populations of galaxies formed in a cosmologically motivated simulation. The calculations include dark matter, gas dynamics, radiation processes, star formation, supernovae…

Using the Hubble Space Telescope, we have resolved individual red-giant branch stars in the halos of eight nearby spiral galaxies. The fields lie at projected distances between 2 and 13 kpc along the galaxies' minor axes. The data set…

Observations of globular clusters (GCs) and field stars in the halos of the giant elliptical galaxy Cen A and the spiral galaxy M31 show a large range of cluster-to-star number ratios ('specific frequencies'). The cluster-to-star ratio…

The present day chemical and dynamical properties of the Milky Way bear the imprint of the Galaxy's formation and evolutionary history. One of the most enduring and critical debates surrounding Galactic evolution is that regarding the…

It is well-established that the vast majority of metal-poor Galactic halo stars shows evidence for enrichment by solely massive stars. Recent observations have identified more varied behavior in the pattern of elemental abundances measured…

The metal-poor stars of a galaxy offer insights into that galaxy's early formation processes and accretion history. Here, we investigate whether the metal-poor stars of our Milky Way galaxy exhibit any characteristic trends in…

We present low-resolution MMT Hectospec spectroscopy of 594 candidate Monoceros stream member stars. Based on strong color-magnitude diagram overdensities, we targeted three fields within the stream's footprint, with 178 deg < l < 203 deg…

Standard cosmology predicts that dwarfs were the first galaxies to be formed in the Universe and that many of them merge afterwards to form bigger galaxies such as the Milky Way. This process would have left behind traces such as tidal…

We present the results of fitting a flexible stellar stream density model to a collection of thirteen streams around the Milky Way, using photometric data from DES, DECaLS, and Pan-STARRS. We construct density maps for each stream and…

Low luminosity galaxies may be the building blocks of more luminous systems. Southern African Large Telescope (SALT) observations of the low luminosity, early-type galaxy NGC59 are obtained and analysed. These data are used to measure the…

The metal content of clusters of galaxies and its relation to their stellar content is revisited making use of a cluster sample for which all four basic parameters are homogeneously measured within consistent radii, namely core-excised…

Hydrodynamical cosmological simulations predict that the metal-free Population III (Pop III) stars were likely very massive and, therefore, short-lived. However, they left their chemical imprint on their descendants, which can also have…

Massive disk galaxies like our Milky Way should host an ancient, metal-poor, and centrally concentrated stellar population. This population reflects the star formation and enrichment in the few most massive progenitor components that…

For several decades, globular clusters have been considered the best example of simple stellar populations, hosting coeval and chemical homogeneous stars. The last decade of spectroscopic and photometric studies has revealed a more complex…

There is now strong evidence that the metal-rich globular clusters (GC) near the center of our Galaxy are associated with the Galactic bulge rather than the disk as previously thought. Here we extend the concept of bulge GCs to the GC…

A stochastic model of the chemical enrichment of metal-poor systems by core-collapse (Type II) supernovae is presented, allowing for large-scale mixing of the enriched material by turbulent motions and cloud collisions in the interstellar…

Globular clusters (GCs), the oldest stellar systems observed in the Milky Way, have for long been considered single stellar populations. As such, they provided an ideal laboratory to understand stellar dynamics and primordial star formation…

Correlations between stellar kinematics and chemical abundances are fossil evidence for evolutionary connections between Galactic structural components. Extensive stellar surveys show that the only tolerably clear distinction between…