We examine the spatial offsets between X-ray point sources and star clusters in three starburst galaxies. We find that the X-ray sources are preferentially located near the star clusters. Because the star clusters are very good tracers of the star formation activity in the galaxies, this indicates that the X-ray sources are young objects associated with current star formation. We find significa...

Globular clusters are among the oldest objects in galaxies, and understanding the details of their formation and evolution can bring valuable insight into the early history of galaxies. Until the late 1970s, globular clusters were thought of to be relatively static stellar systems, a view which was supported by the fact that most observed density profiles of globular clusters can be fitted with...

N–body + hydrodynamical simulations of the formation and evolution of galaxy groups and clusters in a ΛCDM cosmology are used in order to follow the building-up of the colour-magnitude relation in two clusters and in 12 groups. We have found that galaxies, starting from the more massive, move to the Red Sequence (RS) as they get aged over times and eventually set upon a “dead sequence” (DS) onc...

Our Chandra X-ray Observatory archival study of intracluster entropy in a sample of 222 galaxy clusters shows that Hα and radio emission from the brightest cluster galaxy are much more pronounced when the cluster’s core gas entropy is . 30 keV cm2. The prevalence of Hα emission below this threshold indicates that it marks a dichotomy between clusters that can harbor multiphase gas and star form...

The integrated galaxial initial mass function (IGIMF) is the relevant distribution function containing the information on the distribution of stellar remnants, the number of supernovae and the chemical enrichment history of a galaxy. Since most stars form in embedded star clusters with different masses the IGIMF becomes an integral of the assumed (universal or invariant) stellar IMF over the em...

We numerically investigate dynamical and chemical properties of star clusters (open and globular clusters, and “super star clusters”, SSC) formed in interacting/merging galaxies. The investigation is two-fold: (1) large-scale (100pc-100kpc) SPH simulations on density and temperature evolution of gas in interacting/merging galaxies and (2) small-scale ones on the effects of high gas pressure of ...

We investigate the impact of the star formation efficiency in cluster-forming-cores (i.e. local SFE) on the evolution of the mass in star clusters over the age range 1-100Myr, when star clusters undergo their infant weight-loss/mortality phase. Our model builds on the N -body simulation grid of Baumgardt & Kroupa (2007). Assuming a constant formation rate of gas-embedded clusters and a weak tid...

The transformations taking place in late-type galaxies in the environment of rich clusters of galaxies at z = 0 are reviewed. From the handful of late-type galaxies that inhabit local clusters, whether they were formed in-situ and survived as such, avoiding transformation or even destruction or if they are newcomers that recently infall from outside, we can learn an important lesson on the late...

We compare [α/Fe], metallicity, and age distributions of globular clusters in elliptical, lenticular, and spiral galaxies, which we derive from Lick line index measurements. We find a large number of globular clusters in elliptical galaxies that reach significantly higher [α/Fe] values ([α/Fe]>0.5) than any clusters in lenticular and spiral galaxies. Most of these extremely α-enriched globular ...

We have obtained high resolution UV images with the HST+WFPC2 of the central region of the dwarf elliptical galaxy NGC 205. Our images reveal that many of the hot UV stars previously detected and studied from the ground are actually multiple systems, open clusters and star associations. We have performed photometry of two such clusters and we find our data are consistent with stellar ages of 50...