36 research outputs found
Search for Cosmic Strings in CMB Anisotropies
We have searched the 1st-year WMAP W-Band CMB anisotropy map for evidence of
cosmic strings. We have set a limit of at 95% CL for statistical search for a significant number of strings
in the map. We also have set a limit using the uniform distribution of strings
model in the WMAP data with
at 95% CL. And the pattern search technique we developed here set a limit
at 95% CL.Comment: 10 pages, 8 postscript figure
The Validity of the Cosmic String Pattern Search with the Cosmic Microwave Background
We introduce a new technique to detect the discrete temperature steps that
cosmic strings might have left in the cosmic microwave background (CMB)
anisotropy map. The technique provides a validity test on the pattern search of
cosmic strings that could serve as the groundwork for future pattern searches.
The detecting power of the technique is only constrained by two unavoidable
features of CMB data: (1) the finite pixelization of the sky map and (2) the
Gaussian fluctuation from instrumental noise and primordial anisotropy. We set
the upper limit on the cosmic string parameter as at the 95% confidence level (CL) and find that the amplitude of the
temperature step has to be greater than in order to be detected for
the {\it{Wilkinson Microwave Anisotropy Probe (WMAP)}} 3 year data.Comment: 9 pages, 3 figures. Revised for publicatio
Seeking String Theory in the Cosmos
We review the existence, formation and properties of cosmic strings in string
theory, the wide variety of observational techniques that are being employed to
detect them, and the constraints that current observations impose on string
theory models.Comment: 25 pages; contribution for String Cosmology issue of Classical and
Quantum Gravity. References added and other improvements. Matches journal
versio
Brane Inflation and Cosmic String Tension in Superstring Theory
In a simple reanalysis of the KKLMMT scenario, we argue that the slow roll
condition in the D3-anti-D3-brane inflationary scenario in superstring theory
requires no more than a moderate tuning. The cosmic string tension is very
sensitive to the conformal coupling: with less fine-tuning, the cosmic string
tension (as well as the ratio of tensor to scalar perturbation mode) increases
rapidly and can easily saturate the present observational bound. In a
multi-throat brane inflationary scenario, this feature substantially improves
the chance of detecting and measuring the properties of the cosmic strings as a
window to the superstring theory and our pre-inflationary universe.Comment: Combined bounds from WMAP and SDSS Lyman alpha experiments are added
for analysis, changes are added to the tabl