Related papers: Cluster Populations in A115 and A2283
We report H$\alpha$ observations of a sample of very isolated blue compact galaxies (BCGs) located in the direction of large cosmic voids obtained to understand their stellar population compositions, the present star formation (SF)…
Using the optical data from the Wide component of the CFHT Legacy Survey, and new ultraviolet data from GALEX, we study the colours and specific star formation rates (SSFR) of ~100 galaxy clusters at 0.16<z<0.36, over areas extending out to…
Galaxies with stellar masses <10^7 Msun and specific star formation rates sSFR>10^{-7} yr^{-1} were examined on images of the Hubble Space Telescope Frontier Field Parallels for Abell 2744 and MACS J0416.1-02403. They appear as unresolved…
We present the results of a wide-field survey for H-alpha emitting galaxies in the cluster AC114 at z=0.32. Spectra centred on H-alpha at the cluster redshift have been obtained for 586 galaxies to I~22 out to a radius around 2Mpc. At most,…
Rich galaxy clusters in the local Universe show a large population of S0 galaxies (~ 40%) of all luminous galaxies). With increasing redshift the fraction of this S0 galaxy population is observed to strongly decrease (e.g. by a factor ~2-3…
Slit spectra, covering the rest frame near-ultraviolet and blue wavelength regions, are combined with moderately deep g and R images to investigate radial population gradients in the brightest components of six z=0.2 galaxy clusters…
Blue straggler stars present as secure members in the Galactic open clusters form a major challenge to the conventional picture of evolutionary population synthesis based on the stellar evolution theory of single stars, as illustrated in…
We present measurements of the angular correlation function of galaxies selected from a B_J=23.5 multicolour survey of two 5 degree by 5 degree fields located at high galactic latitudes. The galaxy catalogue of approximately 400,000…
We present a study of the evolution of brightest cluster galaxies (BCGs) in a sample of clusters at $0.05 \leq z<0.35$ from the SDSS and WISE with halo masses in the range $6 \times 10^{13}M_\odot$ (massive groups) - $10^{15.5}M_\odot$…
(Abriged) Blue compact galaxies (BCGs) are low-luminosity, metal-poor, gas-rich objects that form stars at high rates, excellent analogs to the high-redshift star-forming galaxy population. Being low-mass starbursts, they also constitute…
We combine JWST/NIRCam imaging and MUSE data to characterize the properties of galaxies in different environmental conditions in the cluster Abell2744 ($z=0.3064$) and in its immediate surroundings. We investigate how galaxy colors,…
We have used the projected two-point correlation function, $w(r_p)$, to investigate the spatial distribution of the 591 galaxies with secure redshifts between $0 \leq z \leq 1.3$ in the five CFRS fields. The slope of the two-point…
A comprehensive multicolor survey was undertaken to investigate global optical properties of Abell clusters of galaxies. This survey was christened the "Low-Redshift Cluster Optical Survey" (LOCOS). LOCOS was devised to search for patterns…
Recent studies have started to cast doubt on the assumption that most stars are formed in clusters. Observational studies of field stars and star cluster systems in nearby galaxies can lead to better constraints on the fraction of stars…
Luminosity functions have been determined for star cluster populations in 20 nearby (4-30 Mpc), star-forming galaxies based on ACS source lists generated by the Hubble Legacy Archive. Comparisons are made with other recently generated…
Clusters of galaxies have an observed over-density of low-luminosity systems in comparison to the field, although it is not yet agreed whether this effect is the result of initial galaxy mass functions that vary with environment or galaxy…
New and archival HST images of the globular cluster systems of 17 relatively nearby galaxies and 6 more distant galaxies have been used to establish the characteristics of GC subpopulations over a range of host galaxy morphological type…
Two-dimensional surface photometry derived from Hubble Space Telescope imaging is presented for a sample of 225 early-type galaxies (assumed to be cluster members) in the fields of 9 clusters at redshifts $0.17 < z < 1.21$. The 94 luminous…
Clusters of galaxies at z>1 are expected to be increasingly active sites of star formation. To test this, an 850um survey was undertaken of eight high-redshift clusters at z=1.6-2.0 using SCUBA-2 on the James Clerk Maxwell Telescope.…
We have analysed images of the field of A2390 obtained with the CFHT and HST. The analysis fits models to bulge and disk components to several hundred galaxies, with about equal samples from the cluster and field. We also have assessed and…