Introduction to Galaxy Group

However this bound is extremely strong and should motivate further work to better model the interaction of charged dark matter with ordered and disordered magnetic fields in galaxies and clusters of galaxies; to develop precise tests for the presence of charged dark matter based on better estimates of angular momentum exchange; and also to better understand how charged dark matter might modify the growth of magnetic fields, and the formation and interaction histories of galaxies, galaxy groups, and clusters.

However, with appropriate means of reconstruction, such visualisation can also be used to bring out the inherent 3D structure that exists in 2D observations of known galaxies, providing new views of these galaxies and visually illustrating the spatial relationships within galaxy groups that are not obvious in 2D.

We present analysis on three intervening H I-C IV absorption systems tracing gas within galaxy group/cluster environments, identified in the $HST$/COS far-UV spectra of the background quasars PG $1148+549$ ($z_{abs}=0.

We use a set of 111 radio-selected AGN at 3 GHz VLA-COSMOS within the X-ray galaxy groups in the COSMOS field.

We present a weak-lensing analysis of X-ray galaxy groups and clusters selected from the XMM-XXL survey using the first-year data from the Hyper Suprime-Cam (HSC) Subaru Strategic Program.

Using the BAHAMAS and MACSIS simulations to obtain $>10,000$ simulated galaxy groups and clusters, we compute three temperature measures and quantify the differences between them.

In this study we quantify the properties of the gas and dark matter around active galactic nuclei (AGN) in simulated galaxy groups and clusters and analyze the effect of AGN feedback on the surrounding intra-cluster (group) medium.

Then we carry out a series of idealized numerical simulations to model the collision of two initially isolated galaxy groups by using the TreePM-SPH GADGET-3 code.

Its group atmosphere appears truncated and deficient when compared with isolated galaxy groups of similar temperatures.

We apply a spectral stacking technique to Westerbork Synthesis Radio Telescope observations to measure the neutral atomic hydrogen content (H i) of nearby galaxies in and around galaxy groups at z < 0.

We analyse the presence of dust around galaxy group members through the reddening of background quasars.

We present deep (250 ks) Chandra observations of the nearby galaxy group NGC 1600, which has at its centre an ultramassive black hole (17±1.

We study a sample of 207 nearby galaxy groups and clusters observed with XMM-Newton.

26}$, similar to galaxy group environments and in line with previous studies for moderate-luminosity X-ray selected AGN.

We construct a catalog of nearby ultra-diffuse galaxies in galaxy group environments, and set upper and lower limits for the possible velocity dispersion allowed in MOND, taking into account possible variations in the mass-to-light ratio of the dwarf and in the distance to the galaxy group.

We run a galaxy group finder and mimic the H i stacking procedure adopted by different surveys and find we can reproduce their observationally derived HIHM relation.

We present a proof of concept of a new galaxy group finder method, Markov graph CLustering (MCL) that naturally handles probabilistic linking criteria.

91 galaxy group RO-1001.

We have discovered a 300 kpc-wide giant Lyman-α (Lyα) nebula centered on the massive galaxy group RO-1001 at z = 2.