Adiabatic versus isocurvature non-Gaussianity

Hikage, Chiaki, Munshi, Dipak, Heavens, Alan and Coles, Peter (2010) Adiabatic versus isocurvature non-Gaussianity. Monthly Notices of the Royal Astronomical Society, 404 (3). pp. 1505-1511. ISSN 0035-8711

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We study the extent to which one can distinguish primordial non-Gaussianity (NG) arising from adiabatic and isocurvature perturbations. We make a joint analysis of different NG models based on various inflationary scenarios: local-type and equilateral-type NG from adiabatic perturbations and local-type and quadratic-type NG from isocurvature perturbations together with a foreground contamination by point sources. We separate the Fisher information of the bispectrum of cosmic microwave background temperature and polarization maps by l for the skew spectrum estimator introduced by Munshi and Heavens to study the scale dependence of the signal-to-noise ratio of different NG components and their correlations. We find that the adiabatic and the isocurvature modes are strongly correlated, though the phase difference of acoustic oscillations helps to distinguish them. The correlation between local- and equilateral-type is weak, but the two isocurvature modes are too strongly correlated to be discriminated. Point source contamination, to the extent to which it can be regarded as white noise, can be almost completely separated from the primordial components for l > 100. Including correlations among the different components, we find that the errors of the NG parameters increase by 20-30 per cent for the Wilkinson Microwave Anisotropy Probe 5-year observation, but ~=5 per cent for Planck observations.

Item Type: Article
Keywords: methods: analytical, methods: statistical, cosmic microwave background, early Universe
Schools and Departments: School of Mathematical and Physical Sciences > Physics and Astronomy
Subjects: Q Science > QB Astronomy > QB0980 Cosmogony. Cosmology
Depositing User: Peter Coles
Date Deposited: 29 Apr 2013 06:43
Last Modified: 03 Jul 2019 02:16

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