相关论文: How supermassive black holes shape central entropi…
We present first results on the cooling properties derived from Chandra X-ray observations of 83 high-redshift (0.3 < z < 1.2) massive galaxy clusters selected by their Sunyaev-Zel'dovich signature in the South Pole Telescope data. We…
The radiative cooling time of the hot gas at the centres of cool cores in clusters of galaxies drops down to 10 million years and below. The observed mass cooling rate of such gas is very low, suggesting that AGN feedback is very tightly…
Recent X-ray observations of intense high-speed outflows in quasars suggest that supercritical accretion on to the central black hole may have an important effect on a host galaxy. I revisit some ideas of Silk and Rees, and assume such…
Supermassive Black Holes (BHs) residing in brightest cluster galaxies (BCGs) are overly massive when considering the local relationships between the BH mass and stellar bulge mass or velocity dispersion. Due to the location of these BHs…
The processes driving gas accretion on to supermassive black holes (SMBHs) are still poorly understood. Angular momentum conservation prevents gas within $\sim10\,$pc of the black hole from reaching radii $\sim10^{-3}\,$pc where viscous…
We use high-resolution cosmological zoom-in simulations to model mechanical and thermal feedback from AGN onto the evolution of Seyfert-type galaxies, studying the morphology of central galaxies growing within dark matter (DM) halos with…
High-resolution simulations of supermassive black holes in isolated galaxies have suggested the importance of short (~10 Myr) episodes of rapid accretion caused by interactions between the black hole and massive dense clouds within the…
In many theoretical scenarios it is expected that intermediate-mass black holes (IMBHs, with masses M ~ 100-10000 solar masses) reside at the centers of some globular clusters. However, observational evidence for their existence is limited.…
Most supermassive black holes (SMBHs) are accreting at very low levels and are difficult to distinguish from the galaxy centers where they reside. Our own Galaxy's SMBH provides a uniquely instructive exception, and we present a close-up…
The binding energy liberated by the coalescence of supermassive black hole (SMBH) binaries during galaxy mergers is thought to be responsible for the low density cores often found in bright elliptical galaxies. We use high-resolution…
We suggest a new picture of supermassive black hole (SMBH) growth in galaxy centers. Momentum-driven feedback from an accreting hole gives significant orbital energy but little angular momentum to the surrounding gas. Once central accretion…
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…
In cool-core galaxy clusters with central cooling times much shorter than a Hubble time, condensation of the ambient central gas is regulated by a heating mechanism, probably an active galactic nucleus (AGN). Previous analytical work has…
We present 1D numerical simulations, which consider the effects of radiative cooling and gravity on the hydrodynamics of the matter reinserted by stellar winds and supernovae within young nuclear starbursts with a central supermassive black…
We studied the thermal stability of non-self-gravitating turbulent $\alpha$-discs around supermassive black holes (SMBHs) to test a new type of high-amplitude galactic nucleus flares. By calculating the disc structures, we computed the…
Super-Eddington accretion onto massive black hole seeds may be commonplace in the early Universe, where the conditions exist for rapid accretion. Direct collapse black holes are often invoked as a possible solution to the observation of…
The early growth of black holes (BHs) in atomic-cooling halos is likely influenced by feedback on the surrounding gas. While the effects of radiative feedback are well-documented, mechanical feedback, particularly from AGN jets, has been…
Super-massive black holes (SMBHs) observed to have masses of $M_\bullet \sim 10^9 \, \mathrm{M_\odot}$ at $z\gtrsim6$, $<1$ Gyr after the Big Bang, are thought to have been seeded by massive black holes which formed before growing…
Jets launched by the supermassive black holes in the centers of cool-core clusters are the most likely heat source to solve the cooling flow problem. One way for this heating to occur is through generation of a turbulent cascade by…
For the recent four years we have been studying feedback heating in cooling flow (CF) clusters by AGN activity that inflate bubbles by jets; this short contribution to a meeting summarizes our main results. To achieve our results we had to…