Related papers: Physically Detached "Compact Groups"
This paper is the first of a series considering the properties of distribution of nearby galaxies in the low density regions. Among 7596 galaxies with radial velocities V_{LG}<3500 km/s, absolute magnitudes M_K<-18.4^m$, and Galactic…
Observations of high redshift galaxies have revealed a multitude of large clumpy rapidly star-forming galaxies. Their formation scenario and their link to present day spirals is still unknown. In this Letter we perform adaptive mesh…
Models of hierarchical galaxy formation predict that large numbers of low-mass, dark matter halos remain around galaxies today. These models predict an order of magnitude more halos than observed stellar satellites in the Local Group. One…
Galaxy groups likely to be virialized are identified within the CNOC2 intermediate redshift galaxy survey using an iterative method. The number-velocity dispersion relation is in agreement with the low-mass extrapolation of the cluster…
A standard method to study the mass distribution in galaxy clusters is through strong lensing of background galaxies in which the positions of multiple images of the same source constrain the surface mass distribution of the cluster.…
The nature of Compact Groups (CGs) is investigated by comparing the luminosities and morphologies of CG galaxies, CG Neighbours and Isolated galaxies. CGs turn out to include more early type galaxies than Isolated galaxies and fewer…
Observations of compact groups of galaxies (CGs) indicate that their abundance has not significantly changed since $z=0.2$. This balance between the timescales for formation and destruction of CGs is challenging if the typical timescale for…
High resolution gravity plus smoothed particle hydrodynamics simulations are used to study the formation of galaxies within the context of hierarchical structure formation. The simulations have sufficient dynamic range to resolve from ten…
We find that the fraction of early-type galaxies in poor groups (containing from 4 to 10 members) is a weakly increasing function of the number of the group members and is about two times higher than in a sample of isolated galaxies. We…
We present preliminary results from a survey of CO emission from members of a volume-limited sample of non-cluster elliptical galaxies. Our intent is to compare the gas properties of these ellipticals to a sample of lenticulars selected…
The diffuse intragroup light (IGL) is a pervasive feature of galaxy groups consisting of an extended low-surface-brightness component that permeates the intergalactic medium of these galaxy associations. It is primarily formed by stars…
Fossil groups are expected to be the final product of galaxy merging within galaxy groups. In simulations, they are predicted to assemble their mass at high redshift. This early formation allows for the innermost $M^\ast$ galaxies to merge…
The galaxies with photometric redshifts observed in a close angular proximity might be either projection coincidences, strongly lensed images of the same galaxy, or separate galaxies that are in a stage of merging. We search for the groups…
We perform a comparative analysis of the properties of galaxies infalling into groups classifying them accordingly to whether they are: falling along filamentary structures; or they are falling isotropically. For this purpose, we identify…
We develop a simple, fast and predictive model of the hierarchical formation of galaxies which is in quantitative agreement with observations. Comparing simulations with observations we place constraints on the density of the universe and…
Most gravitational lens galaxies are early-type galaxies in relatively low density environments. We show that they lie on the same fundamental plane as early-type galaxies in both local and distant rich clusters. Their surface brightness…
We show that, observationally, the projected local density distribution in high-z clusters is shifted towards higher values compared to clusters at lower redshift. To search for the origin of this evolution, we analyze a sample of haloes…
We have obtained $H_{\alpha}$ fluxes and luminosities for a sample of 95 accordant galaxies from observations of 31 Hickson Compact Groups (HCGs) in the North hemisphere. This sample is the largest $H_{\alpha}$ selected catalogue of…
As a result of our statistical study of 540 edge-on galaxies, we present here the images and preliminary statistical analysis of a sub-sample of 60 galaxies, that were selected to be S-type warped spirals. Computing the average volumic…
We review how dark matter is distributed in our local neighbourhood from an observational and theoretical perspective. We will start by describing first the dark matter halo of our own galaxy and in the Local Group. Then we proceed to…