The expected pattern of temperature step is depicted
in Figure 11.
Figure 11. Temperature step configuration by a curvy cosmic string. The
region toward which cosmic string is moving is red shifted and makes a
lower temperature region while opposite side of the string segment is
blue shifted (hotter region).
We search this patterns of temperature anisotropy as a possible signal
from cosmic string.
Two examples of patterns found in the real anisotropy map are shown
below with optimal height of temperature step that fits best with the
Figure 12. Examples of patterns which show long sequences temperature
The pattern on the right has well aligned steps but it is not
consistent with the curvature and resulting velocity configuration of
cosmic string. Therefore, its expected temperature step is zero, i.e..
is not considered as a signal produced by a cosmic string. The pattern
on the left does not look convincing but when taken into account the
background (Gaussian) fluctuation, it meets the requirement for being
pattern produced by a cosmic string with optimal height of step . Collecting
all the patterns found in the CMB anisotropy map, we plot the
distribution of temperature steps in the Figure 13.
Figure 13. Distributions of for WMAP data set, simulated sky
map and white noise.
We estimate from the plots above that and it corresponds to the limit
for the string parameter . The energy scale of symmetry
breaking that is responsible for the production of cosmic string is
related by the string parameter as
the energy scale of symmetry breaking and we find from the limit of
string parameter, .
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