We present Hα-derived star-formation rates (SFRs) for the galaxy cluster CL J0023+0423B at z = 0.845. Our 3σ flux limits corresponds to a star-formation rate of 0.24 h −2 100 M ⊙ yr −1 , and our minimum reliable Hα + [N II] equivalent width is > 10Å, demonstrating that near-infrared narrow-band imaging can sample the star-forming galaxy population in distant clusters. Comparison with spectrosco...

At a redshift of 0.18, Abell 1689 is so far the most distant cluster of galaxies for which substantial mid–infrared (MIR) data have been published. Its mapping with the ISOCAM camera onboard the ISO satellite allowed the detection of 30 cluster members at 6.75 μm (LW2 filter) and 16 cluster members at 15 μm (LW3 filter) within a clustercentric radius of 0.5 Mpc (?) Paper I]Fadda00b. We present ...

The evolution of star clusters is studied using N-body simulations in which the evolution of single stars and binaries are taken self-consistently into account. Initial conditions are chosen to represent relatively young Galactic open clusters, such as the Pleiades, Praesepe and the Hyades. The calculations include a realistic mass function, primordial binaries and the external potential of the...

We report on a study of young star cluster complexes in the spiral galaxy M51. Recent studies have confirmed that star clusters do not form in isolation, but instead tend to form in larger groupings or complexes. We use HST broad and narrow band images (from both WFPC2 and ACS), along with BIMA-CO observations to study the properties and investigate the origin of these complexes. We find that t...

Three-body effects greatly complicate stellar evolution. We model the effects of encounters of binaries with single stars, based on parameters chosen from conditions prevalent in the cores of globular clusters. For our three-body encounters, we start with a population of primordial binaries, and choose incoming stars from the evolving single star populations of paper I. In addition, we study th...

We investigate how the [OII] properties and the morphologies of galaxies in clusters and groups at z = 0.4− 0.8 depend on projected local galaxy density. We also compare our results with those derived from the field at similar redshifts and from clusters at low-z. In both nearby and distant clusters, higher-density regions contain proportionally fewer star-forming galaxies. At odds with low-z r...

We independently redetermine the reddening and age of the globular cluster 037-B327 in M31 by comparing independently obtained multicolour photometry with theoretical stellar population synthesis models. 037-B327 has long been known to have a very large reddening value, which we confirm to be E(B − V) = 1.360 ± 0.013, in good agreement with the previous results. We redetermine its most likely a...

We combine optical (HST) and UV (GALEX) imaging of two intermediate redshift galaxy clusters with spectroscopy of member galaxies, to study the relation between the formation history of cluster galaxies and the assembly history of the cluster structure itself. We identify key differences in the large-scale structure and intracluster medium properties of each cluster. In order to assess the impo...

We present the results of a deep narrow-band [OII] 3727 Å emission-line search for faint (g < 27), star-forming galaxies in the field of the z = 0.37 MS1512.4+3647 cluster. We find no evidence for an over-density of emission-line sources relative to the field at z ∼ 0.4 (Hogg et al. 1998), and therefore conclude that the MS1512.4+3647 sample is dominated by field [OII] emission-line galaxies wh...

We examine the dynamical destruction of binary systems in star clusters of different densities. We find that at high densities (10 − 10 M⊙ pc ) almost all binaries with separations > 10 AU are destroyed after a few crossing times. At low densities (O(102)M⊙ pc ) many binaries with separations > 10 AU are destroyed, and no binaries with separations > 10 AU survive after a few crossing times. The...