相关论文: Cluster cores and cooling flows
We propose a scenario in which a large fraction, or even most, of the gas cooling to low temperatures of T<10^4 K in cooling flow clusters, directly gains energy from the central black hole. Most of the cool gas is accelerated to…
We present the results of a Chandra observation of the cooling core cluster Abell 2063. Spectral analysis shows that there is cool gas (2 keV) associated with the cluster core, which is more than a factor of 2 cooler than the outer cluster…
Clusters of galaxies are thought to contain about ten times as much dark matter as baryonic matter. The dark component therefore dominates the gravitational potential of the cluster, and the baryons confined by this potential radiate X-rays…
Expanding X-ray cavities observed in hot gas atmospheres of many galaxy groups and clusters generate shock waves and turbulence that are primary heating mechanisms required to avoid uninhibited radiatively cooling flows which are not…
Activities of a supermassive black hole or active galactic nucleus in the central galaxy of a cluster of galaxies have been promising candidates for heating sources of cool cluster cores. We estimate the masses of black holes using known…
We present an analysis of 55 central galaxies in clusters and groups with molecular gas masses and star formation rates lying between $10^{8}-10^{11}\ M_{\odot}$ and $0.5-270$ $M_{\odot}\ yr^{-1}$, respectively. We have used Chandra…
I review the literature's census of the cold gas in clusters of galaxies. Cold gas here is defined as the gas that is cooler than X-ray emitting temperatures (~10^7 K) and is not in stars. I present new Spitzer IRAC and MIPS observations of…
New X-ray observations from the {\it Chandra} and XMM-{\it Newton} observatories have shown that cooling of the intracluster medium is occurring at rates that are now approaching the star formation rates measured in cD galaxies at the bases…
Galaxy cluster mass distributions offer an important test of the cold dark matter picture of structure formation, and may even contain clues about the nature of dark matter. X-ray imaging spectroscopy of relaxed systems can map cluster dark…
We carry out high-resolution adaptive mesh refinement simulations of a cool core cluster, resolving the flow from Mpc scales down to pc scales. We do not (yet) include any AGN heating, focusing instead on cooling in order to understand how…
The cooling-flow problem is a long-standing puzzle that has received considerable recent attention, in part because the mechanism that quenches cooling flows in galaxy clusters is likely to be the same mechanism that sharply truncates the…
In many clusters of galaxies there is evidence for cooling flow in the central regions. A possibility is that a fraction of the gas forms cold molecular clouds. We investigate the minimum temperature which can be reached by clouds in…
In the centers of many galaxy clusters, the hot ($\sim$10$^7$ K) intracluster medium (ICM) can become dense enough that it should cool on short timescales. However, the low measured star formation rates in massive central galaxies and…
Cold fronts have been observed in a large number of galaxy clusters. Understanding their nature and origin is of primary importance for the investigation of the internal dynamics of clusters. To gain insight on the nature of these features,…
The Chandra and XMM data for a sample of 19 relaxed groups/poor clusters, covering the temperature range 1-3 keV and selected to have the best available data, reveal a remarkable similarity in their temperature profile: cool cores outside…
Using a set of ROSAT HRI deep pointings, we investigate the presence of small-scale structures in the central regions of clusters of galaxies. Our sample comprises 23 objects up to z=0.32, 13 of them known to host a cooling flow. Structures…
We examine the properties of the X-ray gas in the central regions of the distant (z=0.46), X-ray luminous cluster of galaxies surrounding the powerful radio source 3C 295, using observations made with the Chandra Observatory. Between radii…
A study of the structural and scaling properties of the temperature distribution of the hot, X-ray emitting intra-cluster medium of galaxy clusters, and its dependence on dynamical state, can give insights into the physical processes…
Detection of the copious amount of X-ray emission from the dilute hot plasma in galaxy clusters suggests that a substantial fraction of the central intracluster medium (ICM) is cooling radiatively on a time scale much faster than the Hubble…
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…