Figure 1. The standard cosmological model which
predicts that the Universe is dominated by 74% dark energy and 22% dark
matter. The remaining 4% are the atoms of ordinary matter that we see
around us. Thus in this model 96% of the Universe is dark. (Credit: NASA/WMAP Science Team)
Figure 2. The unresolved radio sources used by
Sawangwit & Shanks to
measure the effect of telescope smoothing are marked on the WMAP CMB
map (open circles). Sawangwit and Shanks found that the radio sources
implied stronger telescope smoothing than previously found, suggesting
that the CMB ripple size may be smaller. Click the image for larger
version (Credit: NASA/WMAP
plus Durham University).
Figure 3. The effect of foreground superclusters on
CMB photons. Two photon paths are shown passing through a galaxy
cluster. Without dark energy (top), a CMB photon gets
gravitationally blueshifted as it enters a cluster and redshifted as it
leaves and the two effects cancel. But with dark energy (bottom), the
cluster galaxies accelerate
away from each other as the photon passes through and the cancellation
is not exact, so that slightly higher CMB temperatures are predicted to
be observed in sightlines that pass near galaxy superclusters. (Credit:
IOP-physicsworld.com)
Figure 4. Darth Vader
from the 'Star Wars' film epic. If the new
results are correct then the evidence for the "Dark Side" of the
Universe may be less compelling than originally believed! (Darth Vader
is TM and copyrighted by Lucasfilm Ltd.)
Further Information
The research on the WMAP "ripples" will appear as a
letter in the journal Monthly Notices
of the Royal Astronomical Society
(MNRAS).
A preprint of the paper is available on the astrophysics e-print arXiv.
The research on the test for dark energy via the
effect of foreground galaxies on the CMB photons has also appeared in
the journal MNRAS (2010MNRAS.402.2228S).
The paper can also be found at arXiv:0911.1352.
A related article which might be of interest can be
found
at arXiv:1006.1270
(presentation given at the conference "45th Rencontres de Moriond" -
Cosmology Session, La Thuile, Val d'Aosta, Italy, March 13 - 20, 2010).
Expanded press release (original draft) is available
here
