Star clusters are observed to form in a highly compact state and with low star-formation efficiencies, and only 10 per cent of all clusters appear to survive to middleand old-dynamical age. If the residual gas is expelled on a dynamical time the clusters disrupt. Massive clusters may then feed a hot kinematical stellar component into their host-galaxy’s field population thereby thickening galac...

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 present the result of a survey for star clusters in M33 using the HST/WFPC2 archive images. We have found 104 star clusters, including 32 new ones, in the images of 24 fields that were not included in the previous studies. Combining these with previous data in the literature, we increase the number of M33 star clusters found in the HST images to 242. We have derived BV I integrated photometr...

As part of an ongoing photometric survey of young Magellanic Cloud clusters we identiied Be stars in NGC 1818 and a nearby smaller cluster in the Large Mag-ellanic Cloud. The neighbouring cluster does not appear to contain any evolved stars, and its sparsely populated main sequence does not extend to stars as massive as in NGC 1818. Both clusters are younger than the surrounding eld population,...

As part of an ongoing photometric survey of young Magellanic Cloud clusters we identified Be stars in NGC 1818 and a nearby smaller cluster in the LargeMagellanic Cloud. The neighbouring cluster does not appear to contain any evolved stars, and its sparsely populated main sequence does not extend to stars as massive as in NGC 1818. Both clusters are younger than the surrounding field population...

The proto-galaxy, cB58, was discovered in the CNOC survey of cluster redshifts. Absorption features reveal that this system is at a redshift of z = 2 : 72, implying an absolute magnitude of M v 26, and a star-formation rate of 4700M yr 1 , making it the most \active" star-forming galaxy. This proto-galaxy is observed to lie close (6 00) to a central cluster galaxy at z = 0 : 373. The X-ray prop...

We present the GALEX NUV (2310Å) and FUV (1530Å) galaxy luminosity functions of the nearby cluster of galaxies A1367 in the magnitude range−20.3 ≤ MAB ≤ −13.3. The luminosity functions are consistent with previous (∼ 2 mag shallower) estimates based on the FOCA and FAUST experiments, but display a steeper faint-end slope than the GALEX luminosity function for local field galaxies. Using spectro...

The population synthesis method is used to study the possibility of explaining the appreciable fraction of the intergalactic type-Ia supernovae (SN Ia), 20 −15%, observed in galaxy clusters (Gal-Yam et al. 2003) when close white dwarf binaries merge in the cores of globular clusters. In a typical globular cluster, the number of merging double white dwarfs does not exceed ∼ 10 per year per avera...

We use N-body simulations to survey the response of embedded star clusters to the dispersal of their parent molecular cloud. The final stages of the clusters can be divided into three classes: the cluster (i) is destroyed, (ii) has a loose structure, and (iii) has a compact core. We are interested in three of the governing parameters of the parent cloud: (i) the mass, (ii) the size, and (iii) t...

A key issue of the star formation process is its independence from the environmental conditions. In particular, it is not clear whether star formation in the outer Galaxy occurs in the same way as in the inner Galaxy. We present preliminary results of the analysis of a ∼ 440Ks ACISChandra observation of NGC1893, a young cluster (∼ 3−4Myrs), far away from the Galactic Center with the aim to stud...