Related papers: The Dynamical Mass of the Coma Cluster from Deep L…

Structure formation models predict that clusters of galaxies contain numerous massive subhalos. The gravity of a subhalo in a cluster compresses the surrounding intracluster gas and enhances its X-ray emission. We present a simple model,…

We study a sample of 148 early-type galaxies in the Coma cluster using SDSS photometry and spectra, and calibrate our results using detailed dynamical models for a subset of these galaxies, to create a precise benchmark for dynamical…

As a continuation of our study of the faint galaxy luminosity function in the Coma cluster of galaxies, we report here on the first spectroscopic observations of very faint galaxies (R $\le$ 21.5) in the direction of the core of this…

Dark energy and dark matter constitute 95% of the observable Universe. Yet the physical nature of these two phenomena remains a mystery. Einstein suggested a long-forgotten solution: gravitationally repulsive negative masses, which drive…

The hot X-ray emitting plasma in galaxy clusters is predicted to have turbulent motions which can contribute around ten percent of the cluster's central energy density. We report deep Chandra X-ray Observatory observations of the Coma…

We present here results from a deep spectroscopic survey of the Coma cluster of galaxies (29 galaxies between 18.98<m_R<21.5). Only 1 of these galaxies is within Coma compared to an expected 6.7 galaxies computed from nearby control fields.…

We investigated the central mass distribution of the luminous infrared galaxy NGC 3256 at a distance of 35 Mpc by using CO(1-0) observations of the Atacama Large Millimeter and sub-millimeter Array (ALMA) and near-IR data of the Two Micron…

We studied the stellar populations, distribution of dark matter, and dynamical structure of a sample of 25 early-type galaxies in the Coma and Abell 262 clusters. We derived dynamical mass-to-light ratios and dark matter densities from…

The Cosmological Constant Lambda, a concept introduced by Einstein in 1917, has been with us ever since in different variants and incarnations, including the broader concept of Dark Energy. Current observations are consistent with a value…

Since the daring intuition by Fritz Zwicky in 1933 about the existence of dark matter in the Universe, in spite of the extensive investigations pursued over a very long lapse of time, the nature of this matter and of its (other than…

We have developed a machine learning algorithm capable of detecting ``out-of-domain data'' for trustworthy cosmological inference. By using data from two separate suites of cosmological simulations, we show that our algorithm is able to…

We conduct the first self-consistent numerical simulations of a recently discovered population of 47 large, faint (ultra-diffuse) galaxies, speculated to lie in the Coma cluster. With structural properties consistent with very large low…

We use the Millennium Simulation series to study how the dynamical state of dark matter halos affects the relation between mass and concentration. We find that a large fraction of massive systems are identified when they are substantially…

With the advent of wide-field cosmological surveys, we are approaching samples of hundreds of thousands of galaxy clusters. While such large numbers will help reduce statistical uncertainties, the control of systematics in cluster masses…

The Coma cluster is the richest and most compact of the nearby clusters, yet there is growing evidence that its formation is still on-going. With a new multi-slit imaging spectroscopy technique pioneered at the 8.2 m Subaru telescope and…

We present an algorithm for inferring the dynamical mass of galaxy clusters directly from their respective phase-space distributions, i.e. the observed line-of-sight velocities and projected distances of galaxies from the cluster centre.…

The massive dark matter halos that host groups and clusters of galaxies have observable properties that appear to be log-normally distributed about power-law mean scaling relations in halo mass. Coupling this assumption with either…

We examine the structure and dynamics of the galaxies in the Coma cluster using a catalog of 552 redshifts including 243 new measurements. The velocity distribution is shown to be non-Gaussian due to structure associated with the group of…

N-body simulations and analytical calculations of the gravitational collapse in an expanding universe predict that halos should form with a diverging inner density profile, the cusp. There are some observational indications that the dark…

We estimated the dynamical surface mass density (Sigma) at the solar Galactocentric distance between 2 and 4 kpc from the Galactic plane, as inferred from the observed kinematics of the thick disk. We find Sigma(z=2 kpc)=57.6+-5.8 Mo pc^-2,…