http://apparentbrightness.net astronomy and stuff Mon, 03 Dec 2007 16:07:54 +0000 http://wordpress.org/?v=2.6.1 en http://apparentbrightness.net/2007/12/03/resolving-gas-dynamics-in-the-circumnuclear-region-of-a-disk-galaxy-in-a-cosmological-simulation/ http://apparentbrightness.net/2007/12/03/resolving-gas-dynamics-in-the-circumnuclear-region-of-a-disk-galaxy-in-a-cosmological-simulation/#comments Mon, 03 Dec 2007 16:07:54 +0000 Thomas Marquart http://apparentbrightness.net/2007/12/03/resolving-gas-dynamics-in-the-circumnuclear-region-of-a-disk-galaxy-in-a-cosmological-simulation/

Levine et al.

http://arxiv.org/abs/0711.3478

Simulation with high dynamic range (1E7) down to 0.1pc, i.e. to the accretion disk of a SMBH.

Global instabilities make things quasi-stable locally due to turbulence.

An exponential density profile for the gas in a disk arises naturally due to this.

]]> http://apparentbrightness.net/2007/12/03/resolving-gas-dynamics-in-the-circumnuclear-region-of-a-disk-galaxy-in-a-cosmological-simulation/feed/ http://apparentbrightness.net/2007/11/07/black-hole-growth-in-hierarchical-galaxy-formation/ http://apparentbrightness.net/2007/11/07/black-hole-growth-in-hierarchical-galaxy-formation/#comments Wed, 07 Nov 2007 09:58:01 +0000 Thomas Marquart http://apparentbrightness.net/2007/11/07/black-hole-growth-in-hierarchical-galaxy-formation/

Malbon et al.

http://arxiv.org/abs/astro-ph/0607424

Black Hole – bulge mass relation

They find that the direct accretion of cold gas during starbursts is an important growth mechanism for lower mass black holes and at high redshift. On the other hand, the re-assembly of pre-existing black hole mass into larger units via merging dominates the growth of more massive black holes at low redshift.

As redshift decreases, progressively less massive black holes have the highest fractional growth rates, in line with recent claims of “downsizing” in quasar activity.

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