We present estimates of the GALEX near-ultraviolet (NUV) and far-ultraviolet (FUV) luminosity functions (LFs) of the Coma cluster, over a total area of ∼9 deg (∼25 Mpc), i.e. from the cluster center to the virial radius. Our analysis represents the widest and deepest UV investigation of a nearby cluster of galaxies made to date. The Coma UV LFs show a faint-end slope steeper than the one observ...

We present Herschel images from the HOBYS key program of the Eagle Nebula (M 16) in the far-infrared and sub-millimetre, using the PACS and SPIRE cameras at 70 μm, 160 μm, 250 μm, 350 μm, 500 μm. M 16, home to the Pillars of Creation, is largely under the influence of the nearby NGC 6611 high-mass star cluster. The Herschel images reveal a clear dust temperature gradient running away from the c...

The η Chamaeleontis star cluster is one of the most important nearby groupings of pre-main sequence (PMS) stars. With accurately known distance, compact structure and highly-coeval intermediate-aged population, the η Cha cluster is an important laboratory for enhancing our understanding of all PMS star evolutionary issues. In this paper, recent results concerning the stellar population are disc...

The intermediate age star cluster W3 (age ≈ 300–500 Myr) in NGC 7252 is the most luminous star cluster known to date with a dynamical mass estimate of 8 ± 2 · 10 7 M ⊙. With an effective radius of about 17.5 pc and a velocity dispersion of 45 kms −1 this object may be viewed as one of the recently discovered ultra-compact dwarf galaxies (UCDs). Its intermediate age, however, precludes an origin...

We present Herschel images from the HOBYS key program of the Eagle Nebula (M 16) in the far-infrared and sub-millimetre, using the PACS and SPIRE cameras at 70 μm, 160 μm, 250 μm, 350 μm, 500 μm. M 16, home to the Pillars of Creation, is largely under the influence of the nearby NGC 6611 high-mass star cluster. The Herschel images reveal a clear dust temperature gradient running away from the c...

Pixel-by-pixel colour-magnitude and colour-colour diagrams – based on a subset of the Hubble Space Telescope Advanced Camera for Surveys Early Release Observations – provide a powerful technique to explore and deduce the star and star cluster formation histories of the Mice and the Tadpole interacting galaxies. In each interacting system we find some 40 bright young star clusters (20 . F606W(ma...

The presence of blue straggler stars (BSs) in star clusters has proven a challenge to conventional simple stellar population (SSP) models. Conventional SSP models are based on the evolution theory of single stars. Meanwhile, the typical locations of BSs in the colour-magnitude diagram of a cluster are brighter and bluer than the main sequence turn-off point. Such loci cannot be predicted by sin...

We analyze the morphological evolution of open clusters and provide shape parameters for 265 clusters. The results show that overall sample becomes more elliptical as they grow older, while their core remains circular or slightly trend to circularize. There is a negative correlation ellipticities with number members A significant between masses also detected log(age/year) $\geq$ 8, suggesting s...