Theoretical Models of X-Ray Emission from Rich Clusters of Galaxies

1981 ◽  
pp. 227-240 ◽  
Author(s):  
Lennox L. Cowie
Keyword(s):  
Theoretical Models ◽  
Clusters Of Galaxies ◽  
X Ray

scholarly journals Number Counts of Clusters of Galaxies in X-ray and Submm Bands

1999 ◽  
Vol 183 ◽  
pp. 255-255 ◽  
Author(s):  
Tetsu Kitayama ◽  
Shin Sasaki ◽  
Yasushi Suto
Keyword(s):  
Theoretical Models ◽  
Model Parameters ◽  
Clusters Of Galaxies ◽  
Cluster Number ◽  
Parameter Region ◽  
X Ray ◽  
Background Radiations ◽  
The Press ◽  
Number Counts ◽  
Acceptable Parameter

We compute the number counts of clusters of galaxies, the logN-logS relation, in several X-ray and submm bands on the basis of the Press—Schechter theory (Kitayama et al. 1998). We pay particular attention to a set of theoretical models which well reproduce the ROSAT 0.5–2 keV band logN-logS (Ebeling et al. 1997; Rosati et al. 1997), and explore possibilities to further constrain the models from future observations with ASCA and/or at submm bands. The latter is closely related to the European PLANCK mission and the Japanese LMSA project. We exhibit that one can break the degeneracy in an acceptable parameter region on the Ω0–σ8 plane by combining the ROSAT logN-logS and the submm number counts. Models which reproduce the ROSAT band logN-logS will have N(> S) ∼ (150–300)(S/10−12 erg cm−2 s−) −1.3 str−1 at S ≳ 10−12 erg cm−2 s−1 in the ASCA 2–10 keV band, and N(> Sv) ∼ (102–104)(Sv/100 mJy)−1.5 str−1 at Sv ≳ 100m J y in the submm (0.85mm) band. The amplitude of the logN-logS is very sensitive to the model parameters in the submm band. We also compute the redshift evolution of the cluster number counts and compare with that of the X-ray brightest Abell-type clusters (Ebeling et al. 1996). The results, although still preliminary, point to low density (Ω0 ∼ 0.3) universes. The contribution of clusters to the X-ray and submm background radiations is shown to be insignificant in any model compatible with the ROSAT logN-logS.

scholarly journals The Impact of Cooling Flows in Clusters of Galaxies

2000 ◽  
Vol 195 ◽  
pp. 199-206
Author(s):  
S. W. Allen
Keyword(s):  
Gravitational Lensing ◽  
Theoretical Models ◽  
Clusters Of Galaxies ◽  
X Ray ◽  
Cooling Flows ◽  
Cooling Flow ◽  
A Value ◽  
Best Fitting ◽  
The Mean ◽  
The Impact

I discuss the impact of cooling flows on the observable X-ray properties of clusters of galaxies. I show that accounting for the effects of cooling flows and subcluster merger events leads to consistent determinations of the distribution of gravitating matter in clusters from X-ray and gravitational lensing studies. Accounting for the effects of cooling flows significantly reduces the scatter in the LBol/TX relation determined for the hottest, most luminous systems and changes the best-fitting slope of the relation to a value close to LBol ∝ T2X, in agreement with theoretical models. A clear segregation between the mean metallicities of cooling-flow and non-cooling-flow clusters is observed, which can be explained by the presence of metallicity gradients in the cooling-flow systems.

scholarly journals Brightest cluster galaxies: the centre can(not?) hold

2020 ◽  
Vol 500 (1) ◽  
pp. 310-318
Author(s):  
Roberto De Propris ◽  
Michael J West ◽  
Felipe Andrade-Santos ◽  
Cinthia Ragone-Figueroa ◽  
Elena Rasia ◽  
...  
Keyword(s):  
Dark Matter ◽  
Local Environment ◽  
Major Axis ◽  
Theoretical Models ◽  
Dark Matter Halo ◽  
Gas Distribution ◽  
X Ray ◽  
Cluster Galaxies ◽  
Peculiar Velocities ◽  
Brightest Cluster Galaxies

ABSTRACT We explore the persistence of the alignment of brightest cluster galaxies (BCGs) with their local environment. We find that a significant fraction of BCGs do not coincide with the centroid of the X-ray gas distribution and/or show peculiar velocities (they are not at rest with respect to the cluster mean). Despite this, we find that BCGs are generally aligned with the cluster mass distribution even when they have significant offsets from the X-ray centre and significant peculiar velocities. The large offsets are not consistent with simple theoretical models. To account for these observations BCGs must undergo mergers preferentially along their major axis, the main infall direction. Such BCGs may be oscillating within the cluster potential after having been displaced by mergers or collisions, or the dark matter halo itself may not yet be relaxed.

scholarly journals A Systematic X‐Ray Search for Clusters of Galaxies behind the Milky Way. II. The Second CIZA Subsample

2007 ◽  
Vol 662 (1) ◽  
pp. 224-235 ◽  
Author(s):  
Dale D. Kocevski ◽  
Harald Ebeling ◽  
Chris R. Mullis ◽  
R. Brent Tully
Keyword(s):  
Milky Way ◽  
Clusters Of Galaxies ◽  
X Ray

scholarly journals On the relation between mini-halos and AGN feedback in clusters of galaxies

2020 ◽  
Vol 499 (2) ◽  
pp. 2934-2958
Author(s):  
A Richard-Laferrière ◽  
J Hlavacek-Larrondo ◽  
R S Nemmen ◽  
C L Rhea ◽  
G B Taylor ◽  
...  
Keyword(s):  
Large Scale ◽  
State Of The Art ◽  
Vital Role ◽  
Clusters Of Galaxies ◽  
Relativistic Jets ◽  
X Ray ◽  
Core Cluster ◽  
Central Galaxy ◽  
Central Regions ◽  
Radio Power

ABSTRACT A variety of large-scale diffuse radio structures have been identified in many clusters with the advent of new state-of-the-art facilities in radio astronomy. Among these diffuse radio structures, radio mini-halos are found in the central regions of cool core clusters. Their origin is still unknown and they are challenging to discover; less than 30 have been published to date. Based on new VLA observations, we confirmed the mini-halo in the massive strong cool core cluster PKS 0745−191 (z = 0.1028) and discovered one in the massive cool core cluster MACS J1447.4+0827 (z = 0.3755). Furthermore, using a detailed analysis of all known mini-halos, we explore the relation between mini-halos and active galactic nucleus (AGN) feedback processes from the central galaxy. We find evidence of strong, previously unknown correlations between mini-halo radio power and X-ray cavity power, and between mini-halo and the central galaxy radio power related to the relativistic jets when spectrally decomposing the AGN radio emission into a component for past outbursts and one for ongoing accretion. Overall, our study indicates that mini-halos are directly connected to the central AGN in clusters, following previous suppositions. We hypothesize that AGN feedback may be one of the dominant mechanisms giving rise to mini-halos by injecting energy into the intra-cluster medium and reaccelerating an old population of particles, while sloshing motion may drive the overall shape of mini-halos inside cold fronts. AGN feedback may therefore not only play a vital role in offsetting cooling in cool core clusters, but may also play a fundamental role in re-energizing non-thermal particles in clusters.

Macromolecular Structure Visualization Tools at NCMI

2000 ◽  
Vol 6 (S2) ◽  
pp. 282-283
Author(s):  
Matthew Dougherty ◽  
Wah Chiu
Keyword(s):  
Human Factors ◽  
3D Visualization ◽  
Three Dimensional ◽  
Theoretical Models ◽  
Biological Research ◽  
Macromolecular Structure ◽  
X Ray ◽  
Visualization Tools ◽  
Types Of Information ◽  
3D Em

Sophisticated tools are needed to examine the results of cyro-microscopy. As the size and resolution of three dimensional macromolecular structures steadily improve, and the speed at with which they can be generated increases, researchers are finding they are inundated with larger datasets and at the same time are compelled to expediently evaluate these structures in unforeseen ways. Integration of EM data with other types of information is becoming necessary and routine; for example X-ray data, 3D EM reconstructions, and theoretical models, must be evaluated in concert to discount or propose hypothesis. To create such tools, the developer must take into account not only the empirical and theoretical possibilities, but also they must master the human factors and computational limits. During the last five years, the National Center for Macromolecular Imaging (NCMI) has progressed from a remedial 3D visualization capability to a collection of visualization tools allowing researchers to focus on the discovery phase of biological research.

scholarly journals A ROSAT study of the cores of clusters of galaxies -- I. Cooling flows in an X-ray flux-limited sample

1998 ◽  
Vol 298 (2) ◽  
pp. 416-432 ◽  
Author(s):  
C. B. Peres ◽  
A. C. Fabian ◽  
A. C. Edge ◽  
S. W. Allen ◽  
R. M. Johnstone ◽  
...  
Keyword(s):  
Clusters Of Galaxies ◽  
Limited Sample ◽  
X Ray ◽  
Cooling Flows

scholarly journals X-Ray Emission from Clusters of Galaxies

1984 ◽  
Vol T7 ◽  
pp. 157-162 ◽  
Author(s):  
R F Mushotzky
Keyword(s):  
Clusters Of Galaxies ◽  
X Ray

scholarly journals X-ray clusters of galaxies as tracers of structure in the Universe

Nature ◽  
2001 ◽  
Vol 409 (6816) ◽  
pp. 39-45 ◽  
Author(s):  
Stefano Borgani ◽  
Luigi Guzzo
Keyword(s):  
Clusters Of Galaxies ◽  
X Ray ◽  
The Universe

scholarly journals The Close AGN Reference Survey (CARS)

2018 ◽  
Vol 618 ◽  
pp. A27 ◽  
Author(s):  
M. C. Powell ◽  
B. Husemann ◽  
G. R. Tremblay ◽  
M. Krumpe ◽  
T. Urrutia ◽  
...  
Keyword(s):  
Ambient Medium ◽  
Theoretical Models ◽  
Ionized Gas ◽  
X Ray ◽  
Gas Streams ◽  
Hot Gas ◽  
Upper Limits ◽  
Theoretical Predictions ◽  
Different Origins

Aims. We probe the radiatively-efficient, hot wind feedback mode in two nearby luminous unobscured (type 1) AGN from the Close AGN Reference Survey (CARS), which show intriguing kpc-scale arc-like features of extended [O III]ionized gas as mapped with VLT-MUSE. We aimed to detect hot gas bubbles that would indicate the existence of powerful, galaxy-scale outflows in our targets, HE 0227–0931 and HE 0351+0240, from deep (200 ks) Chandra observations. Methods. By measuring the spatial and spectral properties of the extended X-ray emission and comparing with the sub kpc-scale IFU data, we are able to constrain feedback scenarios and directly test if the ionized gas is due to a shocked wind. Results. No extended hot gas emission on kpc-scales was detected. Unless the ambient medium density is low (n H  ∼  1 cm−3 at 100 pc), the inferred upper limits on the extended X-ray luminosities are well below what is expected from theoretical models at matching AGN luminosities. Conclusions. We conclude that the highly-ionized gas structures on kpc scales are not inflated by a hot outflow in either target, and instead are likely caused by photoionization of pre-existing gas streams of different origins. Our nondetections suggest that extended X-ray emission from an AGN-driven wind is not universal, and may lead to conflicts with current theoretical predictions.

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