منابع مشابه
Agn Feedback Causes Downsizing
We study the impact of outflows driven by active galactic nuclei (AGN) on galaxy formation. Outflows move into the surrounding intergalactic medium (IGM) and heat it sufficiently to prevent it from condensing onto galaxies. In the dense, high-redshift IGM, such feedback requires highly energetic outflows, driven by a large AGN. However, in the more tenuous low-redshift IGM, equivalently strong ...
متن کاملLow accretion rates at the AGN cosmic downsizing epoch
Context. X-ray surveys of Active Galactic Nuclei (AGN) indicate “cosmic downsizing”, with the comoving number density of highluminosity objects peaking at higher redshifts (z ∼ 2) than low-luminosity AGN (z < 1). Aims. We test whether downsizing is caused by activity shifting towards low-mass black holes accreting at near-Eddington rates, or by a change in the average rate of accretion onto sup...
متن کاملAGN Feedback Mechanisms
Accreting black holes can release enormous amounts of energy to their surroundings, in various forms. Such feedback may profoundly influence a black hole’s environment. After briefly reviewing the possible types of feedback, I focus on the injection of kinetic energy through jets and powerful winds. The effects of these outflows may be especially apparent in the heating of the X-ray–emitting at...
متن کاملAGN feedback by relativistic jets
Feedback provided by relativistic jets may be effective in shaping the galaxy luminosity function. The quenching mode (quasar mode) at redshifts ∼2-3 potentially disperses gas in star-forming galaxies. The maintenance mode (radio mode) heats the gas in galaxy clusters counteracting cooling flows. A number of authors have examined the effect of relativistic jets in dispersing clouds in the kpc-s...
متن کاملRapidly varying accretion and AGN feedback
Accretion rates onto AGN are likely to be extremely variable on short timescales; much shorter than the typical cooling time of X-ray emitting gas in elliptical galaxies and galaxy clusters. Using the Langevin approach it is shown that, for a simple feedback system, this can induce variability in the AGN power output that is of much larger amplitude, and persists for longer timescales, than the...
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ژورنال
عنوان ژورنال: The Astrophysical Journal
سال: 2005
ISSN: 0004-637X,1538-4357
DOI: 10.1086/499271