Related papers: Heated Cooling Flows
The present structure of galaxies is governed by the radiative dissipation of the gravitational and supernova energy injected during formation. A crucial aspect of this process is whether the gas cools as fast as it falls into the…
The lack of very cool gas at the cores of groups and clusters of galaxies, even where the cooling time is significantly shorter than the Hubble time, has been interpreted as evidence of sources that re-heat the intergalactic medium. Most…
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…
Massive galaxies in cooling flow clusters display clear evidence of feedback from Active Galactic Nuclei (AGN). Joint X-ray and radio observations have shown that AGN radio jets push aside the surrounding hot gas and form cavities in the…
Three comments are made on AGN heating of cooling flows. A simple physical argument is used to show that the enthalpy of a buoyant radio lobe is converted to heat in its wake. Thus, a significant part of ``cavity'' enthalpy is likely to end…
The quenching "maintenance'" and related "cooling flow" problems are important in galaxies from Milky Way mass through clusters. We investigate this in halos with masses $\sim 10^{12}-10^{14}\,{\rm M}_{\odot}$, using non-cosmological…
I review the multiphase cooling flow equations that reduce to a relatively simple form for a wide class of self-similar density distributions described by a single parameter, $k$. It is shown that steady-state cooling flows are \emph{not}…
AGN outflows are the heat given up when gas in a galaxy evolves towards thermodynamic equilibrium. Indeed, while AGN feedback regulates the growth of massive galaxies, its origins can be understood as the spontaneous thermodynamic process…
We examine the thermodynamic state and cooling of the low-$z$ Circum-Galactic Medium (CGM) in five FIRE-2 galaxy formation simulations of Milky Way-mass galaxies. We find that the CGM in these simulations is generally multiphase and…
Many galaxy clusters pose a "cooling-flow problem", where the observed X-ray emission from their cores is not accompanied by enough cold gas or star formation. A continuous energy source is required to balance the cooling rate over the…
Recently, we have uncovered Hidden Cooling Flows (HCF) in the X-ray spectra of the central Brightest Galaxies of 11 clusters, 1 group and 2 elliptical galaxies. Here we report such flows in a further 15 objects, consisting of 8 clusters, 3…
(Abridged) We present observations of the cluster of galaxies associated with the X-ray source RX J0820.9+0752 and its dramatic central cluster galaxy (CCG) in the optical and X-ray wavebands.Unlike other cooling flow CCGs studied in…
We present a spherically-symmetric, steady-state model of galaxy clusters in which radiative cooling from the hot gas is balanced by heat transport through turbulent mixing. We assume that the gas is in hydrostatic equilibrium, and describe…
Observed accretion rates onto the Milky-Way and other local spirals fall short of that required to sustain star formation for cosmological timescales. A potential avenue for this unseen accretion is an inflow in the volume-filling hot phase…
The results of hydrodynamic simulations of the Virgo and Perseus clusters suggest that thermal conduction is not responsible for the observed temperature and density profiles. As a result it seems that thermal conduction occurs at a much…
We investigate the cold and warm gas content, kinematics, and spatial distribution of six local massive elliptical galaxies to probe the origin of the multiphase gas in their atmospheres. We report new observations, including SOFIA [CII],…
In the prevailing model of galaxy formation and evolution, the process of gas accretion onto central galaxies undergoes a transition from cold-dominated to hot-dominated modes. This shift occurs when the mass of the parent dark matter halos…
Galaxy clusters are filled with hot, diffuse X-ray emitting plasma, with a stochastically tangled magnetic field whose energy is close to equipartition with the energy of the turbulent motions \cite{zweibel1997, Vacca}. In the cluster…
The characterization of the large amount of gas residing in the galaxy halos, the so called circumgalactic medium (CGM), is crucial to understand galaxy evolution across cosmic time. We focus here on the the cool ($T\sim10^4$ K) phase of…
Based on high-resolution two-dimensional hydrodynamic simulations, we show that the bulk gas motions in a cluster of galaxies, which are naturally expected during the process of hierarchical structure formation of the universe, have a…