Related papers: Helium Sedimentation and the UV Upturn in Brightes…
The puzzling origin of the ``UV-upturn'' phenomenon, observed in some elliptical galaxies, has recently been settled by identifying hot HB stars as main contributors to galaxy ultraviolet luminosity excess. While a blue HB morphology seems…
We investigate a recent claim that observed galaxy clusters produce an order of magnitude more galaxy-galaxy strong lensing (GGSL) than simulated clusters in a LCDM cosmology. We take galaxy clusters from the C-EAGLE hydrodynamical…
(abridged) Recent spectroscopic and photometric observations show the existence of various generations of stars in GCs, differing in the abundances of products of H-burning at high temperatures (the main final product being He). It is…
The formation process of fossil groups (FGs) is still under debate, and large samples of such objects are still missing. The aim of this paper is to increase the sample of known FGs, and to analyse the properties of their brightest group…
Various galactic globular clusters display abundance anomalies that affect the morphology of their colour-magnitude diagrams. In this paper we consider the possibility of helium enhancement in the anomalous horizontal branch of NGC 2808. We…
We investigate the rest-frame Ultraviolet (UV, $\lambda\sim2000$\AA) surface brightness (SB) evolution of galaxies up to $z\sim6$ using a variety of deep Hubble Space Telescope imaging. UV SB is a measure of the density of emission from…
Globular clusters host multiple stellar populations that display star-to-star variation of light elements that are affected by hot hydrogen burning (e.g., He, C, N, O). Several scenarios have been suggested to explain these variations. Most…
Recent observations have successfully detected UV or infrared flux from galaxies at the epoch of reionization. However, the origin of their radiative properties has not been fully understood yet. Combining cosmological hydrodynamic…
Surface brightness evolution has been detected in elliptical galaxies (consistent with passive evolution models of old stellar populations) and in disk galaxies (presumably due to enhanced star-formation rates). The rates of evolution in…
We derive apparent and absolute ultraviolet (UV) magnitudes, and luminosities in the infrared (IR) range of a large sample of low-redshift (0<z<1) compact star-forming galaxies (CSFGs) selected from the Data Release 12 of the Sloan Digital…
The James Webb Space Telescope (JWST) has revealed an unexpectedly high abundance of UV luminous galaxies at redshifts $z\gtrsim 10$, challenging `standard' galaxy formation models. This study investigates the role of rapidly rotating…
We study the star-formation activity in a sample of $\sim$ 56,000 brightest cluster galaxies (BCGs) at $0.05 < z < 0.42$ using optical and infra-red data from SDSS and WISE. We estimate stellar masses and star-formation rates (SFR) through…
We examine the environmental effects on the photometric properties of galaxies for the rich galaxy cluster ABCG 209 at z=0.209. We use archive CFHT optical imaging of a 42'x28' field centred on the cluster to produce a galaxy sample…
We analyze the stellar growth of Brightest Cluster Galaxies (BCGs) produced by cosmological zoom-in hydrodynamical simulations of the formation of massive galaxy clusters. The evolution of the stellar mass content is studied considering…
We present a joint analysis of near-ultraviolet (NUV) data from the GALEX mission and (optical) colour profiles for a sample of 7 Brightest Cluster Galaxies (BCGs) in the Canadian Cluster Comparison Project. We find that every BCG which has…
We identify a total of 120 early-type Brightest Cluster Galaxies (BCGs) at 0.1<z<0.4 in two recent large cluster catalogues selected from the Sloan Digital Sky Survey (SDSS). They are selected with strong emission lines in their optical…
Assembly bias, which is the variation in halo clustering at fixed mass driven by formation history, has long been predicted by numerical simulations but remains difficult to confirm observationally. Previous studies have reported evidence…
The diffuse ultraviolet background radiation has been mapped over most of the sky with 2\arcmin \ resolution using data from the \textit{GALEX} survey. We utilize this map to study the correlation between the UV background and clusters of…
Contradictory results have been reported on the time evolution of the alignment between clusters and their Brightest Cluster Galaxy (BCG). We study this topic by analyzing cosmological hydro-simulations of 24 massive clusters with…
The numerous and massive young star clusters in blue compact galaxies (BCGs) are used to investigate the properties of their hosts. We test whether BCGs follow claimed relations between cluster populations and their hosts, such as the the…