Apparent Brightness

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

Thomas Marquart — 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.

Monolithic or hierarchical star formation? A new statistical analysis

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

Kampakoglou et al.
http://arxiv.org/abs/0709.1104
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.

Star-formation in the HI bridge between M81 and M82

Thomas Marquart — 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.

The MW is an exceptionnally quiet galaxy: implications for spiral formation

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

Puech et al.
http://arxiv.org/abs/0711.2881
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.

The Polarization of Scattered Lyman Alpha Radiation Around High-Redshift Galaxies

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

Dijkstra et al.
http://arxiv.org/abs/0711.2312
numerical study of how LyA photons scatter and become polarizes
difference for infall and outflow of gas
polarimetric measurements proposed

IMAGES I. Strong evolution of galaxy kinematics since z=1

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

Yang et al.
http://arxiv.org/abs/0711.2305
large project with the IFU-mode of FLAMES at the VLT.
z=1 galaxies show more frequently “strange” kinematics than locally.

PhD Comics on Astrophysics

Thomas Marquart — Tue, 20 Nov 2007 13:24:08 +0000

Here and here. Funny as usual.