arXiv subjects

N. Simatos

Publications and source records attributed to N. Simatos.

2 recordsLinked to original sources

arXiv2000

Construction of Cosmic String Induced Temperature Anisotropy Maps with CMBFAST and Statistical Analysis

We use the publicly available code CMBFAST as modified by L. Pogosian and T. Vachaspati to simulate the effects of wiggly cosmic strings on the Cosmic Microwave Background (CMB). Using the modified CMBFAST code which takes into account vector modes and models wiggly cosmic strings by the one scale model, we go beyond the angular power spectrum to construct CMB temperature maps with resolution of a few degrees. The statistics of these maps are then studied using conventional and recently proposed statistical tests optimized for the detection of hidden temperature discontinuities induced by the Gott-Kaiser-Stebbins effect. We show however, that these realistic maps can not be distinguished in a statistically significant way from purely Gaussian maps with identical power spectrum.

astro-ph↗

arXiv1998

Hints of Cosmic String Induced Discontinuities in the COBE Data?

We apply new statistical tests on the four year 53 GHz DMR data and show that there is significant probability for the existence of coherent temperature discontinuities hidden in the CMB maps around the Galactic Poles. Comparing Monte Carlo simulations with the DMR maps we find that the probability for the existence of a coherent discontinuity with amplitude $0.2 \times ({{δT} \over T})_{rms}$ superposed on the gaussian fluctuations is more than double than the corresponding probability when no discontinuity is present. This result is consistent with the existence of a horizon size long cosmic string with mass per unit length $μ$ given by $Gμv_s γ_s \simeq 10^{-6}/π$ where $v_s$ is the string velocity and $γ_s$ is the corresponding Lorentz factor.

astro-ph↗