Related papers: Candidate fossil groups in the CFHTLS: a probabili…
We review the formation and evolution of fossil groups and clusters from both the theoretical and the observational points of view. In the optical band, these systems are dominated by the light of the central galaxy. They were interpreted…
[Abridged] HST WFPC2 images were taken of four low surface brightness galaxies in the direction of the Virgo cluster. The high resolution of the WFPC2 combined with the extremely diffuse nature of the four galaxies makes them essentially…
Massive high-redshift galaxies form in over-dense regions where the probability of forming other galaxies is also strongly enhanced. Given an observed flux of a galaxy, the inferred mass of its host halo tends to be larger as its inferred…
We present three candidate clusters of galaxies at redshifts most likely between 1.7 and 2.0, which corresponds to a fundamentally unexplored epoch of clusters evolution. The candidates were found by studying the environment around our…
We discuss the angular clustering of galaxy clusters at z > 1 selected within 50 sq. deg from the Spitzer Wide-Infrared Extragalactic survey. We employ a simple color selection to identify high redshift galaxies with no dependence on galaxy…
We report on the detection of four primordial galaxies candidates in the redshift range 4.55 < z < 4.76, as well as 4 other candidates in the range 4.12 < z < 4.32. These galaxies have been detected with the now common technique of the…
We present a statistical analysis of the properties of a large sample of dynamically hot old stellar systems, from globular clusters to giant ellipticals, which was performed in order to investigate the origin of ultra-compact dwarf…
Understanding the mechanisms that lead dense environments to host galaxies with redder colors, more spheroidal morphologies, and lower star formation rates than field populations remains an important problem. As most candidate processes…
The whole Sloan Digital Sky Survey (SDSS, 14,555 deg^2 has been searched for intergalactic globular clusters (IGCs) in the Local Group (LG). Using optical, infrared, and ultraviolet photometric selection criteria and photometric redshifts,…
Galaxy pairs may represent a way station in the evolutionary path from poor groups to giant isolated ellipticals (or fossil groups). To test this evolutionary scenario, we investigated the environment of 4 galaxy pairs composed of a giant…
The dwarf galaxies of the Local Group are believed to be similar to the most abundant galaxies during the epoch of reionization (z>6). As a result of their proximity, there is a wealth of information that can be obtained about these…
We report the discovery of a candidate galaxy with a photo-z of z~12 in the first epoch of the JWST Cosmic Evolution Early Release Science (CEERS) Survey. Following conservative selection criteria we identify a source with a robust z_phot =…
Identifying galaxy groups from redshift surveys of galaxies plays an important role in connecting galaxies with the underlying dark matter distribution. Current and future high-$z$ spectroscopic surveys, usually incomplete in redshift…
As the environment harbouring the majority of galaxies, filaments are thought to play a key role in the co-evolution of galaxies and the cosmic web. In this first part of a series to understand the link between galaxies and filaments…
Bulges are a major galaxy component in the nearby universe, and are one of the primary features that differentiates and defines galaxies. The origin of bulges can be directly probed in part by examining distant galaxies to search for high…
We use a combination of high-resolution gasdynamics simulations of high-redshift dwarf galaxies and dissipationless simulations of a Milky Way sized halo to estimate the expected abundance and spatial distribution of the dwarf satellite…
Massive clusters of galaxies have been found as early as 3.9 Billion years (z=1.62) after the Big Bang containing stars that formed at even earlier epochs. Cosmological simulations using the current cold dark matter paradigm predict these…
The most prodigious starburst galaxies are absent in massive galaxy clusters today, but their connection with large scale environments is less clear at $z\gtrsim2$. We present a search of large scale structure around a galaxy cluster core…
The PSCz redshift survey and the ongoing Two-Degree Field Galaxy Redshift Survey (2dFGRS) are used to look for luminosity dependence of galaxy clustering by measuring the two point correlation functions for sub-samples of the surveys. An…
Galaxies that are being stripped of their gas can sometimes be recognized from their optical appearance. Extreme examples of stripped galaxies are the so-called ``jellyfish galaxies'', that exhibit tentacles of debris material with a…