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Extracting primordial non-gaussianity without cosmic variance


Seljak, U (2009). Extracting primordial non-gaussianity without cosmic variance. Physical Review Letters, 102(2):021302.

Abstract

Recent work has emphasized the possibility to probe non-Gaussianity of local type by measuring the power spectrum of highly biased tracers of large scale structure on very large scales. This method is limited by the cosmic variance, by the finite number of structures on the largest scales, and by the partial degeneracy with other cosmological parameters that can mimic the same effect. We propose an alternative method based on the fact that on large scales, halos are linearly biased, but not stochastic, tracers of dark matter: by correlating a highly biased tracer of large scale structure against an unbiased tracer, one eliminates the cosmic variance error, which can lead to a significant increase in signal to noise. For an ideal survey out to z∼2, the error reduction can be as large as a factor of 7, which should guarantee a detection of non-Gaussianity from an all-sky survey of this type.

Abstract

Recent work has emphasized the possibility to probe non-Gaussianity of local type by measuring the power spectrum of highly biased tracers of large scale structure on very large scales. This method is limited by the cosmic variance, by the finite number of structures on the largest scales, and by the partial degeneracy with other cosmological parameters that can mimic the same effect. We propose an alternative method based on the fact that on large scales, halos are linearly biased, but not stochastic, tracers of dark matter: by correlating a highly biased tracer of large scale structure against an unbiased tracer, one eliminates the cosmic variance error, which can lead to a significant increase in signal to noise. For an ideal survey out to z∼2, the error reduction can be as large as a factor of 7, which should guarantee a detection of non-Gaussianity from an all-sky survey of this type.

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Additional indexing

Other titles:Measuring primordial non-gaussianity without cosmic variance
Item Type:Journal Article, refereed, original work
Communities & Collections:07 Faculty of Science > Institute for Computational Science
Dewey Decimal Classification:530 Physics
Language:English
Date:January 2009
Deposited On:27 Feb 2010 13:15
Last Modified:07 Dec 2017 00:52
Publisher:American Physical Society
ISSN:0031-9007
Funders:Packard Foundation, Swiss National Foundation [200021-116696/1]
Publisher DOI:https://doi.org/10.1103/PhysRevLett.102.021302
Related URLs:http://arxiv.org/abs/0807.1770

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