Galactic Pancake Mystery Solved

mOoZik writes "According to the BBC, Astronomers have figured out why a series of small galaxies surrounding the Milky Way are distributed around it in the shape of a pancake. Theorists believed that the eleven dwarf galaxy companions should have a diffuse, spherical arrangement, but a University of Durham team used a supercomputer to show how the galaxies could take the pancake form without challenging cosmological theory."

Comments

In depth ...

[foobsr]

... and more credit ... (and to enhance discussion :) ...

Full article

The Distribution of Satellite Galaxies: The Great Pancake

Noam I Libeskind, Carlos S Frenk, Shaun Cole, John C Helly, Adrian Jenkins, Julio F Navarro and Chris Power

ABSTRACT
The 11 known satellite galaxies within 250 kpc of the Milky Way lie close to a great circle on the sky. We use high resolution N-body simulations of galactic dark matter halos to test if this remarkable property can be understood within the context of the cold dark matter cosmology. We construct halo merger trees from the simulations and use a semianalytic model to follow the formation of satellite galaxies. We find that in all 6 of our simulations, the 11 brightest satellites are indeed distributed along thin, disk-like structures analogous to that traced by the Milky Way's satellites. This is in sharp contrast to the overall distributions of dark matter in the halo and of subhalos within it which, although triaxial, are not highly aspherical. We find that the spatial distribution of satellites is significantly different from that of the most massive subhalos but is similar to that of the subset of subhalos that had the most massive progenitors at earlier times. The elongated disk-like structure delineated by the satellites has its long axis aligned with the major axis of the dark matter halo. We interpret our results as reflecting the preferential infall of satellites along the spines of a few filaments of the cosmic web.

CC.

Re:In depth ...

[stygianguest]

From what they understand they just showed that the available theories (well, the ones they chose to use) already give an explanation of the current situation.

Re:Way to go, University of Wherever

[Tim C]

Well, maybe *you've* never heard of the University of Durham, but it's one of the foremost universities in the UK, and the Physics group there is extremely well-respected.

This isn't "some kids doing a group project", this is proper academic research; you may have heard of that...