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 Color Maps of A 1795 and A 2597 - Cooling Flow Cluster Central Galaxies with Active Nuclei

1989 ◽  
Vol 134 ◽  
pp. 460-461
Author(s):  
W. Romanishin
Keyword(s):  
Star Formation ◽  
Clusters Of Galaxies ◽  
Nuclear Activity ◽  
X Ray ◽  
Cluster Galaxies ◽  
Cooling Flows ◽  
Cooling Flow ◽  
Show Evidence ◽  
The Subject ◽  
Optical Manifestation

The subject of cooling flows in clusters of galaxies remains a controversial one, primarily because many clusters which have large x-ray derived mass inflow rates do not show any optical manifestation of the inflow or of the final fate of the gas. However, a handful of cooling flow clusters do show extended blue continuum regions indicative of current star formation which may be caused by the cooling flows (Romanishin 1987, Romanishin and Hintzen 1988), while another group show spectral evidence of star formation (O'Connell and McNamara 1988). Most of the cluster galaxies which show evidence of star formation also show nuclear activity, in the form of radio emission.

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

Weak Gravitational Lensing by a Sample of X‐Ray–luminous Clusters of Galaxies. II. Comparison with Virial Masses

2002 ◽  
Vol 579 (1) ◽  
pp. 227-235 ◽  
Author(s):  
Ragnvald J. Irgens ◽  
Per B. Lilje ◽  
Hakon Dahle ◽  
S. J. Maddox
Keyword(s):  
Gravitational Lensing ◽  
Clusters Of Galaxies ◽  
Weak Gravitational Lensing ◽  
X Ray

scholarly journals Magnetic fields, winds and X-rays of massive stars in the Orion nebula cluster

2010 ◽  
Vol 6 (S272) ◽  
pp. 208-209 ◽  
Author(s):  
Véronique Petit ◽  
Gregg A. Wade ◽  
Evelyne Alecian ◽  
Laurent Drissen ◽  
Thierry Montmerle ◽  
...  
Keyword(s):  
Magnetic Fields ◽  
Massive Stars ◽  
Theoretical Models ◽  
Magnetic Star ◽  
X Rays ◽  
Orion Nebula ◽  
X Ray ◽  
Ob Stars ◽  
The Impact ◽  
The Relationship

AbstractIn some massive stars, magnetic fields are thought to confine the outflowing radiatively-driven wind. Although theoretical models and MHD simulations are able to illustrate the dynamics of such a magnetized wind, the impact of this wind-field interaction on the observable properties of a magnetic star - X-ray emission, photometric and spectral variability - is still unclear. The aim of this study is to examine the relationship between magnetism, stellar winds and X-ray emission of OB stars, by providing empirical observations and confronting theory. In conjunction with the COUP survey of the Orion Nebula Cluster, we carried out spectropolarimatric ESPaDOnS observations to determine the magnetic properties of massive OB stars of this cluster.

scholarly journals Highly-luminous Cool Core Clusters of Galaxies: Mechanically-driven or Radiatively-driven AGN?

2010 ◽  
Vol 6 (S277) ◽  
pp. 329-332
Author(s):  
Julie Hlavacek-Larrondo ◽  
Andy Fabian
Keyword(s):  
Surrounding Medium ◽  
Clusters Of Galaxies ◽  
X Ray ◽  
Energy Feedback ◽  
Bolometric Luminosity ◽  
Strong Energy ◽  
The Mean ◽  
Intracluster Gas ◽  
Jet Power ◽  
Very High

AbstractCool core clusters of galaxies require strong feedback from their central AGN to offset cooling. We present a study of strong cool core, highly-luminous (most with Lx ≥ 1045 erg s−1), clusters of galaxies in which the mean central AGN jet power must be very high yet no central point X-ray source is detected. Using the unique spatial resolution of Chandra, a sample of 13 clusters is analysed, including A1835, A2204, and one of the most massive cool core clusters, RXCJ1504.1-0248. All of the central galaxies host a radio source, indicating an active nucleus, and no obvious X-ray point source. For all clusters in the sample, the nucleus has an X-ray bolometric luminosity below 2 per cent of that of the entire cluster. We investigate how these clusters can have such strong X-ray luminosities, short radiative cooling-times of the inner intracluster gas requiring strong energy feedback to counterbalance that cooling, and yet have such radiatively-inefficient cores with, on average, Lkin/Lnuc exceeding 200. Explanations of this puzzle carry significant implications for the origin and operation of jets, as well as on establishing the importance of kinetic feedback for the evolution of galaxies and their surrounding medium.

Weak Gravitational Lensing by a Sample of X‐Ray Luminous Clusters of Galaxies. I. The Data Set

2002 ◽  
Vol 139 (2) ◽  
pp. 313-368 ◽  
Author(s):  
Hakon Dahle ◽  
Nick Kaiser ◽  
Ragnvald J. Irgens ◽  
Per B. Lilje ◽  
Steve J. Maddox
Keyword(s):  
Gravitational Lensing ◽  
Clusters Of Galaxies ◽  
Data Set ◽  
Weak Gravitational Lensing ◽  
X Ray

scholarly journals Precessing AGN jets, bubbles and cooling flows

2010 ◽  
Vol 6 (S275) ◽  
Author(s):  
D. Falceta-Gonçalves ◽  
A. Caproni ◽  
Z. Abraham ◽  
E. M. de Gouveia Dal Pino ◽  
D. M. Teixeira
Keyword(s):  
Galaxy Clusters ◽  
Flow Problem ◽  
X Rays ◽  
Intracluster Medium ◽  
X Ray ◽  
Cooling Flows ◽  
Cooling Flow ◽  
Central Regions ◽  
Multiple Bubbles ◽  
Hydrodynamical Simulations

AbstractSeveral galaxy clusters are known to present multiple and misaligned pairs of cavities seen in X-rays, as well as twisted kiloparsec-scale jets at radio wavelengths. It suggests that the AGN precessing jets play a role in the formation of the misaligned bubbles. Also, X-ray spectra reveal that typically these systems are also able to supress cooling flows, predicted theoretically. The absence of cooling flows in galaxy clusters has been a mistery for many years since numerical simulations and analytical studies suggest that AGN jets are highly energetic, but are unable to redistribute it at all directions. We performed 3D hydrodynamical simulations of the interaction between a precessing AGN jet and the warm intracluster medium plasma, in which dynamics is coupled to a NFW dark matter gravitational potential. Radiative cooling has been taken into account and the cooling flow problem was studied. We found that precession is responsible for multiple pairs of bubbles, as observed. The misaligned bubbles rise up to scales of tens of kiloparsecs, where the thermal energy released by the jets are redistributed. After ~150 Myrs, the temperature of the gas within the cavities is kept of order of ~107 K, while the denser plasma of the intracluster medium at the central regions reaches T ~ 105 K. The existence of multiple bubbles, at diferent directions, results in an integrated temperature along the line of sight much larger than the simulations of non-precessing jets. This result is in agreement with the observations. The simulations reveal that the cooling flows cessed ~50–70 Myr after the AGN jets are started.

scholarly journals Gravitational Lensing of the X‐Ray Background by Clusters of Galaxies

1997 ◽  
Vol 478 (2) ◽  
pp. 476-491 ◽  
Author(s):  
Alexandre Refregier ◽  
Abraham Loeb
Keyword(s):  
Gravitational Lensing ◽  
Clusters Of Galaxies ◽  
X Ray ◽  
X Ray Background
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