Material for the Royal Astronomical Society press release RAS PR 12/36
25 April 2012
The original RAS press release can be found here: http://www.ras.org.uk/news-and-press/219-news-2012/2118-do-the-milky-ways-companions-spell-trouble-for-dark-matter
The release is based on the paper "The VPOS: a vast polar structure of satellite galaxies, globular clusters and streams around the Milky Way" , accepted for publication in MNRAS.
Credit: NASA, ESA, the Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration, and A. Evans (University of Virginia, Charlottesville/NRAO/Stony Brook University)
Different sizes and original caption available at the HubbleSite.
Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)
Different sizes and original caption available at the HubbleSite.
Description:
Animated version of Figure 5 in Pawlowski et al. (2012):
The vast polar structure -- VPOS -- about the MW in Cartesian coordinates. The movie rotates the view over 360 degree, adding different objects around the Milky Way galaxy. One kpc (a common length-scale in astronomy) is 1000 parsec, with one parsec being 3.26 light years. The y-axis points towards the Galactic north pole. The 11 classical satellites are shown as yellow dots, the 13 new satellites are represented by the smaller green dots, young halo globular clusters are plotted as blue squares. The red curves connect the anchor points of streams of stars and gas, the (light-red) shaded regions illustrating the planes defined by these and the Galactic centre. Note that the stream coordinates are magnified by a factor of 3 to ease the comparison. The obscuration-region 10 degree around the Milky Way disc is given by the horizontal grey areas. In the centre, the Milky Way disc orientation (edge-on) is shown by a short horizontal cyan line. One can clearly see when the view is edge-on to the VPOS: The extend of all types of objects becomes minimal, also the streams align preferentially with this structure. From standard dark matter cosmology, a much more spheroidal distribution of objects around the Milky Way is expected. We therefore propose the satellite galaxies of the Milky Way to be Tidal Dwarf Galaxies.
REFERENCE: M. S. Pawlowski, J. Pflamm-Altenburg, P. Kroupa: "The VPOS: a vast polar structure of satellite galaxies, globular clusters and streams around the Milky Way", MNRAS, 2012
Credit: Marcel S. Pawlowski, University of Bonn
YouTube link: http://www.youtube.com/watch?v=nUwxv-WGfHM
Download: VPOS.m4v (7 MB)
See the original press release for full contact information.
PhD student of astronomy in Bonn. Member of the Bonn-Cologne Graduate School of Physics and Astronomy
Email: mpawlow@astro.uni-bonn.de