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

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The mean redshift of the core of the Coma cluster - cz = 6953 km s^{-1} and its dispersion \sigma=949 km s^{-1} are obtained by means of the analysis of the substructures of this cluster by using the S-tree method. The existence of three…

Astrophysics · Physics 2008-11-26 V. G. Gurzadyan , A. Mazure

Nearly seventy per cent of the energy density in the universe is unclustered and exerts negative pressure. This conclusion -- now supported by numerous observations -- poses the greatest challenge for theoretical physics today. I discuss…

Astrophysics · Physics 2009-07-09 T. Padmanabhan

Since the 1930s, astronomical observations have accumulated evidence that our understanding of the dynamics of galaxies and groups of galaxies is grossly incomplete: assuming the validity of Newton's law of gravity on astronomical scales,…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-18 Sascha Trippe

We present updated cosmological constraints from measurements of the gas mass fractions ($f_{gas}$) of massive, dynamically relaxed galaxy clusters. Our new data set has greater leverage on models of dark energy, thanks to the addition of…

The spin of galaxy clusters encodes key information about their formation, dynamics, and the influence of large-scale structure. However, whether clusters possess statistically significant spin and how to measure it observationally remain…

Astrophysics of Galaxies · Physics 2025-11-25 Xiao-xiao Tang , Peng Wang , Yu Rong , Weiguang cui , Min Bao

The Coma supercluster (100 Mpc) offers an unprecedented contiguous range of environments in the nearby Universe. In this paper we present a catalogue of spectroscopically confirmed galaxies in the Coma supercluster detected in the…

Astrophysics of Galaxies · Physics 2018-06-06 Smriti Mahajan , Ankit Singh , Devika Shobhana

The hypothesis of the scale invariance of the macroscopic empty space, which intervenes through the cosmological constant, has led to new cosmological models. They show an accelerated cosmic expansion and satisfy several major cosmological…

Astrophysics of Galaxies · Physics 2017-11-15 Andre Maeder

Clusters of galaxies, being dark matter dominated, have long been and still are the ideal cosmological targets to study the nature of dark matter. Constraints on the nature of dark matter comes in particular from the observational…

Cosmology and Nongalactic Astrophysics · Physics 2020-01-06 A. Biviano

Quantum theory, general relativity, the standard model of particle physics, and the $\Lambda$CDM model of cosmology have all been spectacularly successful within their respective regimes of applicability, but many central problems remain…

General Physics · Physics 2026-05-26 Roland E. Allen

On the cosmological length scale, recent measurements by WMAP have validated $\Lambda$CDM to a precision not see before in cosmology. Such is not the case on galactic length scales, however, where the `cuspy-core' problem has demonstrated…

Astrophysics · Physics 2007-12-05 A. D. Speliotopoulos

We demonstrate the ability of convolutional neural networks (CNNs) to mitigate systematics in the virial scaling relation and produce dynamical mass estimates of galaxy clusters with remarkably low bias and scatter. We present two models,…

Cosmology and Nongalactic Astrophysics · Physics 2020-12-23 Matthew Ho , Markus Michael Rau , Michelle Ntampaka , Arya Farahi , Hy Trac , Barnabas Poczos

We discuss the possibility that the cold dark matter mass profiles contain information on the cosmological constant, and that such information constrains the nature of cold dark matter (CDM). We call this approach Modified Dark Matter…

Cosmology and Nongalactic Astrophysics · Physics 2017-07-26 Doug Edmonds , Duncan Farrah , Chiu Man Ho , Djordje Minic , Y. Jack Ng , Tatsu Takeuchi

The new dynamical theory of space is further confirmed by showing that the black hole masses M_BH in 19 spherical star systems, from globular clusters to galaxies with masses M, satisfy the prediction that M_BH=(alpha/2)M, where alpha is…

General Physics · Physics 2007-05-23 Reginald T Cahill

The homogeneous expansion history H(z) of our universe measures only kinematic variables, but cannot fix the underlying dynamics driving the recent acceleration: cosmographic measurements of the homogeneous universe, are consistent with…

Astrophysics · Physics 2007-10-24 Sidney Bludman

Strong lensing studies can provide detailed mass maps of the inner regions even in dynamically active galaxy clusters. It is shown that proper modelling of the intracluster medium, i.e. the main baryonic component, can play an important…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 M. Sereno , M. Lubini , Ph. Jetzer

In 1900 it was believed that almost 100% of the mass of the Universe resided in stars. Now, in the year 2000, such stars (and cold gas) are known to account for only ~1% its mass. The remaining mass of the Universe is thought to reside in…

Astrophysics · Physics 2007-05-23 Sidney van den Bergh

A large spectroscopic survey is constructed of galaxies in the Coma cluster. The survey covers a wide area (1 deg$^2$) to deep magnitudes (R ~ 19.5), covering both the core (high density) and outskirts (intermediate to low density) of the…

A new universal constant of expansion has been discovered with amazing predictive power once its density-time relations have been deciphered. The new constant is kappa, the product of the gravitational constant, and the average total…

Astrophysics · Physics 2007-05-23 Charles B. Leffert

Two very different methods are used to estimate the magnitude of the effective cosmological constant / dark energy (for the present cosmic epoch). Their results agree with each other and are in agreement with observations. One method makes…

General Relativity and Quantum Cosmology · Physics 2017-06-15 Y. Jack Ng

We report the discovery of 854 ultra diffuse galaxies (UDGs) in the Coma cluster using deep R band images, with partial B, i, and Halpha band coverage, obtained with the Subaru telescope. Many of them (332) are Milky Way-sized with very…

Astrophysics of Galaxies · Physics 2015-06-08 Jin Koda , Masafumi Yagi , Hitomi Yamanoi , Yutaka Komiyama