1. Estimating the bispectrum of the Very Small Array data.
- Author
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Sarah Smith, Graça Rocha, Anthony Challinor, Richard A. Battye, Pedro Carreira, Kieran Cleary, Rod D. Davies, Richard J. Davis, Clive Dickinson, Ricardo Genova-Santos, Keith Grainge, Carlos M. Gutiérrez, Yaser A. Hafez, Michael P. Hobson, Michael E. Jones, Rudiger Kneissi, Katy Lancaster, Anthony Lasenby, J. P. Leahy, and Klaus Maisinger
- Subjects
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COSMIC ripples , *DATA analysis , *COSMIC background radiation , *GAUSSIAN distribution , *SIMULATION methods & models , *SPECTRUM analysis , *METAPHYSICAL cosmology - Abstract
We estimate the bispectrum of the Very Small Array data from the compact and extended configuration observations released in 2002 December, and compare our results with those obtained from Gaussian simulations. There is a slight excess of large bispectrum values for two individual fields, but this does not appear when the fields are combined. Given our expected level of residual point sources, we do not expect these to be the source of the discrepancy. Using the compact configuration data, we put an upper limit of 5400 on the value of fNL, the non-linear coupling parameter, at 95 per cent confidence. We test our bispectrum estimator using non-Gaussian simulations with a known bispectrum, and recover the input values. [ABSTRACT FROM AUTHOR]
- Published
- 2004
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