Apparent Brightness » Galaxies

Resolving Gas Dynamics in the Circumnuclear Region of a Disk Galaxy in a Cosmological Simulation

Thomas — Mon, 03 Dec 2007 16:07:54 +0000

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.

Thomas — Mon, 03 Dec 2007 15:35:59 +0000

Statistical model to predict/fit the star formation history of the universe. Hierarchical formation through merging seems to be favoured but not enough to exclude the monolithic scenario. Outflow models and dust are critical.
My impression is that the two priciple modes of galaxy formation seem to be subject to fashion among astronomers. While monolithic has been favoured in the early days of extragalacitc astronomy, the hierarchical formation was preferred until lately when it was realised that the former probably also plays a role.

Thomas — Tue, 20 Nov 2007 14:13:50 +0000

de Mello et al.
http://arxiv.org/abs/0711.2685
They found both old and young stars in the region between the two galaxies and conclude that the former were flung out of either of the two while the latter have formed in the tidal tail.

Overall, there seems to be quite little going on there compared to other tidal tails (e.g. of mergers) where active star formation is often seen.

Thomas — Tue, 20 Nov 2007 14:06:40 +0000

Conference proceeding on how the MW is special in the sense that it forms little stars and therefore cannot have undergone a merger for a long time.

Thomas — Tue, 20 Nov 2007 13:32:25 +0000

Thomas — Tue, 20 Nov 2007 13:29:15 +0000

Thomas — Tue, 13 Nov 2007 08:33:25 +0000

GCs can be “friendless”, meaning they have no neighbors with similar kinematics. In addition they look at various subsamples depending e.g. on metallicity and brightness.

Thomas — Mon, 12 Nov 2007 19:40:43 +0000

Nesvadba et al.
http://arxiv.org/abs/0711.1491
the title says it.
two blobs rotating around each other without velocity difference over each of them.

Thomas — Mon, 12 Nov 2007 12:14:02 +0000

Kaviraj et al.
http://arxiv.org/abs/0711.1493
Simulations on how minor mergers can explain the variation in UV-fluxes of ellipticals.

They say they cannot “rule out” gas accretion, but I wonder where the dividing line goes between a gas-rich dwarf being eaten and infall of gas.

Thomas — Wed, 07 Nov 2007 10:03:56 +0000

Grillo et al.
http://arxiv.org/abs/0711.0882
Combining gravitational lensing and galaxy dynamics (velocity dispersion as a funciton of radius in ellipticals) as a new and independant (!) method of measuring the geometry of the universe.