360,833 research outputs found

    Simulation of Cosmic Microwave Background Polarization Fields for AMiBA Experiment

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    We have made a topological study of cosmic microwave background (CMB) polarization maps by simulating the AMiBA experiment results. A Λ\LambdaCDM CMB sky is adopted to make mock interferometric observations designed for the AMiBA experiment. CMB polarization fields are reconstructed from the AMiBA mock visibility data using the maximum entropy method. We have also considered effects of Galactic foregrounds on the CMB polarization fields. The genus statistic is calculated from the simulated QQ and UU polarization maps, where QQ and UU are Stokes parameters. Our study shows that the Galactic foreground emission, even at low Galactic latitude, is expected to have small effects on the CMB polarization field. Increasing survey area and integration time is essential to detect non-Gaussian signals of cosmological origin through genus measurement.Comment: 7 pages, 4 figures, Accepted version for publication in the Journal of the Korean Astronomical Societ

    Multi-frequency imaging of perfectly conducting cracks via boundary measurements

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    Imaging of perfectly conducting crack(s) in a 2-D homogeneous medium using boundary data is studied. Based on the singular structure of the Multi-Static Response (MSR) matrix whose elements are normalized by an adequate test function at several frequencies, an imaging functional is introduced and analyzed. A non-iterative imaging procedure is proposed. Numerical experiments from noisy synthetic data show that acceptable images of single and multiple cracks are obtained.Comment: 4 pages, 3 figure
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