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Galaxy clusters are the most recent, gravitationally-bound products of the hierarchical mass accretion over cosmological scales. How the mass is concentrated is predicted to correlate with the total mass in the cluster's halo, with systems…

Cosmology and Nongalactic Astrophysics · Physics 2016-06-01 Stefania Amodeo , Stefano Ettori , Raffaella Capasso , Mauro Sereno

Using a hydrodynamics plus N-body simulation of galaxy cluster formation within a large volume and mock Chandra X-ray observations, we study the form and evolution of the intrinsic scatter about the best-fit X-ray temperature-mass relation…

Astrophysics · Physics 2011-02-11 H. -Y. Yang , P. M. Ricker , P. M. Sutter

The temperature and density of the hot diffuse medium pervading galaxy groups and clusters combine into one significant quantity, the entropy. Here we express the entropy levels and profiles in model-independent forms by joining two…

Astrophysics · Physics 2009-11-13 A. Cavaliere , A. Lapi , Y. Rephaeli

We present CHANDRA X-ray and NTT optical observations of the distant z=0.52 galaxy cluster RBS380 -- the most distant cluster of the ROSAT Bright Source (RBS) catalogue. We find diffuse, non-spherically symmetric X-ray emission with a X-ray…

Astrophysics · Physics 2008-11-26 Rodrigo Gil-Merino , Sabine Schindler

Recent XMM-Newton observations of clusters of galaxies have indicated the soft X-ray spectra to be inconsistent with the simple isobaric cooling flow model. There is almost no feature of the cold gas expected from the model. This shows that…

Astrophysics · Physics 2015-06-24 Shin Sasaki , Noriko Y. Yamasaki

The relationships between the X-ray determined bolometric luminosity Lx, the temperature T of the intracluster gas, and the optical measured velocity dispersion sigma of the cluster galaxies are updated for galaxy clusters using the largest…

Astrophysics · Physics 2009-10-31 Xiang-Ping Wu , Yan-Jie Xue , Li-Zhi Fang

We examine the X-ray luminosity of galaxy groups in the CNOC2 survey, at redshifts 0.1 < z < 0.6. Previous work examining the gravitational lensing signal of the CNOC2 groups has shown that they are likely to be genuine, gravitationally…

Astrophysics · Physics 2009-01-19 David S. Spiegel , Frits Paerels , Caleb A. Scharf

The properties of X-ray clusters of galaxies can be well understood in terms of a competition between shock heating and adiabatic compression. Strong shocks are expected to be important for massive clusters, while adiabatic compression is…

Astrophysics · Physics 2009-10-31 Paolo Tozzi , Colin Norman

Chandra has significantly advanced our knowledge of the processes in the intracluster gas. The discovery of remarkably regular ``cold fronts'', or contact discontinuities, in merging clusters showed that gas dynamic instabilities at the…

Astrophysics · Physics 2007-05-23 M. Markevitch , A. Vikhlinin , W. R. Forman

(Abridged) We present in this paper a sample of 14 nearby clusters of galaxies observed with the ROSAT/PSPC. We only select clusters with low galactic nH in order to trace the X-ray emitting intra-cluster medium (ICM) out to large radii. We…

Astrophysics · Physics 2009-11-11 D. M. Neumann

It is generally argued that most clusters of galaxies host cooling flows in which radiative cooling in the centre causes a slow inflow. However, recent observations by Chandra and XMM conflict with the predicted cooling flow rates. It has…

Astrophysics · Physics 2009-11-07 M. Bruggen

We present gas and total mass profiles for 13 low-redshift, relaxed clusters spanning a temperature range 0.7-9 keV, derived from all available Chandra data of sufficient quality. In all clusters, gas temperature profiles are measured to…

Astrophysics · Physics 2010-11-11 A. Vikhlinin , A. Kravtsov , W. Forman , C. Jones , M. Markevitch , S. S. Murray , L. Van Speybroeck

We present a $Chandra$ study of the hot intragroup medium (hIGM) of the galaxy group NCG2563. The $Chandra$ mosaic observations, with a total exposure time of ~430 ks, allow the gas density to be detected beyond $R_{200}$ and the gas…

Cosmology and Nongalactic Astrophysics · Physics 2017-05-03 Andrea Morandi , Ming Sun , John Mulchaey , Daisuke Nagai , Massimiliano Bonamente

Many processes within galaxy clusters, such as those believed to govern the onset of thermally unstable cooling and AGN feedback, are dependent upon local dynamical timescales. However, accurately mapping the mass distribution within…

Astrophysics of Galaxies · Physics 2017-03-08 M. T. Hogan , B. R. McNamara , F. Pulido , P. E. J. Nulsen , H. R. Russell , A. N. Vantyghem , A. C. Edge , R. A. Main

We consider a sample of 22 nearby clusters of galaxies observed with the Medium Energy Concentrator Spectrometer (MECS) on board of BeppoSAX. They cover the range in gas temperature between 3 and 10 keV, with bolometric X-ray luminosity…

Astrophysics · Physics 2009-11-07 S. Ettori , S. De Grandi , S. Molendi

It is shown that the low-mass groups obey the $L_{x}\sim\sigma_v^{4}$ law deduced for galaxy clusters. The impression of the more shallow slope of the $L_x-\sigma_{v}$ correlation for groups is created not by enhanced X-ray emission, but by…

Astrophysics · Physics 2009-11-07 H. M. Tovmassian , O. Yam , H. Tiersch

We present ASCA X-ray observations of a sample of five groups selected from a cross-correlation of the ROSAT All-Sky Survey with the White et al. optical catalog of groups. These X-ray bright groups significantly increase the number of…

Almost all of the extragalactic X-ray background (XRB) at 0.25 keV can be accounted for by radio-quiet quasars, allowing us to derive an upper limit of 4 \bgunit\ for the remaining background at 0.25 keV. However, the XRB from the gas halos…

Astrophysics · Physics 2009-09-17 K. K. S. Wu , A. C. Fabian , P. E. J. Nulsen

Observational studies of cluster evolution over moderate redshift ranges (to z ~ 1) are a powerful tool for constraining cosmological parameters, yet a comprehensive knowledge of the properties of these clusters has been hitherto…

Astrophysics · Physics 2007-05-23 Amalia Hicks , Erica Ellingson , Mark Bautz , Howard Yee , Mike Gladders , Gordon Garmire

In the outskirts of galaxy clusters, entropy profiles measured from X-ray observations of the hot intracluster medium (ICM) drops off unexpectedly. One possible explanation for this effect is gas clumping, where pockets of cooler and denser…

Instrumentation and Methods for Astrophysics · Physics 2023-10-06 Christian T. Norseth , Daniel R. Wik , John A. ZuHone , Eric D. Miller , Marshall W. Bautz , Michael McDonald
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