Searcharxiv⌕ Search
Home/Archive/arXiv

arXiv · astro-ph/0201349

Recent CHANDRA and XMM observations of two very different galaxy clusters: RBS797 and CL 0939+4713

E. De Filippis·S. Schindler·A. Castillo-Morales
View original source ↗Read source document ↗Export metadata ↓

Abstract

RBS797 and CL 0939+4713 are two intermediate red-shift clusters ($z=0.35-0.41$). They have very different morphologies but both show surprisingly interesting structures. RBS797 looks relaxed, with an almost circular morphology; a CHANDRA observation of this cluster has revealed two deep depressions in the X-ray emission near the core. CL 0939+4713 has instead an irregular morphology with evident substructures which seem to be in the process of merging.

Explore related subjects

astro-ph

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

E. De Filippis, S. Schindler, A. Castillo-Morales. 2002-01-21. Recent CHANDRA and XMM observations of two very different galaxy clusters: RBS797 and CL 0939+4713. https://arxiv.org/abs/astro-ph/0201349

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2022

A Revolution in Science: the Eclipse Expeditions of 1919

The first direct experimental test of Einstein's theory of general relativity involved a pair of expeditions to measure the bending of light at a total solar eclipse that took place one hundred years ago, on 29 May 1919. So famous is this experiment, and so dramatic was the impact on Einstein himself, that history tends not to recognise the controversy that surrounded the results at the time. In this article, I discuss the experiment in its scientific and historical background context and explain why it was, and is, such an important episode in the development of modern physics.

astro-ph↗
arXiv2022

State Vector Determination By A Single Tracking Satellite

Using only a single tracking satellite capable of only range measurements to an orbiting object in an unknown Keplerian orbit, it is theoretically possible to calculate the orbit and a current state vector. In this paper we derive an algorithm that can perform this calculation.

astro-ph↗
arXiv2022

Dark Matter and Dark Energy

I briefly review our current understanding of dark matter and dark energy. The first part of this paper focusses on issues pertaining to dark matter including observational evidence for its existence, current constraints and the `abundance of substructure' and `cuspy core' issues which arise in CDM. I also briefly describe MOND. The second part of this review focusses on dark energy. In this part I discuss the significance of the cosmological constant problem which leads to a predicted value of the cosmological constant which is almost $10^{123}$ times larger than the observed value $\la/8πG \simeq 10^{-47}$GeV$^4$. Setting $\la$ to this small value ensures that the acceleration of the universe is a fairly recent phenomenon giving rise to the `cosmic coincidence' conundrum according to which we live during a special epoch when the density in matter and $\la$ are almost equal. Anthropic arguments are briefly discussed but more emphasis is placed upon dynamical dark energy models in which the equation of state is time dependent. These include Quintessence, Braneworld models, Chaplygin gas and Phantom energy. Model independent methods to determine the cosmic equation of state and the Statefinder diagnostic are also discussed. The Statefinder has the attractive property $\atridot/a H^3 = 1 $ for LCDM, which is helpful for differentiating between LCDM and rival dark energy models. The review ends with a brief discussion of the fate of the universe in dark energy models.

astro-ph↗