Constraining Running Non-Gaussianity

By E. Sefusatti, M. Liguori, A. Yadav, M. Jackson, E. Pajer. 2009

132 citations recorded by the source corpus.

The primordial non-Gaussian parameter fNL has been shown to be scale-dependent in several models of inflation with a variable speed of sound. Starting from a simple ansatz for a scale-dependent amplitude of the primordial curvature bispectrum for two common phenomenological models of primordial non-Gaussianity, we perform a Fisher matrix analysis of the bispectra of the temperature and polarization of the Cosmic Microwave Background (CMB) radiation and derive the expected constraints on the parameter nNG that quantifies the running of fNL(k) for current and future CMB missions such as WMAP, Planck and CMBPol. We find that CMB information alone, in the event of a significant detection of the non-Gaussian component, corresponding to fNL = 50 for the local model and fNL = 100 for the equilateral model of non-Gaussianity, is able to determine nNG with a 1-sigma uncertainty of Delta nNG = 0.1 and Delta nNG = 0.3, respectively, for the Planck mission. In addition, we consider a Fisher matrix analysis of the galaxy power spectrum to determine the expected constraints on the running parameter nNG for the local model and of the galaxy bispectrum for the equilateral model from future photometric and spectroscopic surveys. We find that, in both cases, large-scale structure observations should achieve results comparable to or even better than those from the CMB, while showing some complementarity due to the different distribution of the non-Gaussian signal over the relevant range of scales. Finally, we compare our findings to the predictions on the amplitude and running of non-Gaussianity of DBI inflation, showing how the constraints on a scale-dependent fNL(k) translate into constraints on the parameter space of the theory.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/8c045d4d3194124f166f927eddd9c1b19ae7d452

How researchers see this paper

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In Astronomy and Astrophysics

1. L. Senatore
2. D. Baumann
3. M. Zaldarriaga
4. D. Green
5. A. Banday
6. Xingang Chen
7. Uros Seljak
8. H. Eriksen

In Nuclear and High Energy Physics

1. L. Senatore
2. D. Baumann
3. Liam McAllister
4. C. Byrnes
5. Kiwoon Choi
6. Xingang Chen
7. D. Green
8. A. Banday

Citations in the corpus

• Primordial non-Gaussianity from the large-scale structure (2010, background): “It is expected that future all-sky galaxy surveys will achieve constraints of the order of ∆f loc NL ∼ 1 assuming all systematics are reasonably under control [95, 148, 149, 158, 137, 204, 205, 206].”
• Planck 2015 results. XVII. Constraints on primordial non-Gaussianity (2015, unknown): “Alternatively, but not equivalently, factorizability can be preserved by replacing the arithmetic mean of the three wavenumbers with the geometric mean (Sefusatti et al. 2009):”
• The Effective Field Theory of Large Scale Structures at two loops (2013, methodology): “Preliminary forecasts for these parameters for the Euclid survey [29], using kmax ' 0.”
• Inflation and String Theory (2014, background): “Large-scale structure constraints on the running of the spectrum were analyzed in [721].”
• Planck 2018 results. IX. Constraints on primordial non-Gaussianity (2019, methodology): “Alternatively, but not equivalently, factorizability can be preserved by replacing the arithmetic mean of the three wavenumbers with the geometric mean (Sefusatti et al. 2009):”
• Constraining primordial non-Gaussianity with future galaxy surveys (2011, background): “These constraints are similar to to the forecasted limits from the Planck CMB bispectrum (Sefusatti et al. 2009), and fully independent.”
• General CMB and primordial bispectrum estimation: Mode expansion, map making, and measures of F NL (2009, background): “[15] Emiliano Sefusatti, Michele Liguori, Amit P.”
• Review of local non-Gaussianity from multi-field inflation (2010, background): “Observational prospects for this quantity were considered in [144], who showed that the Planck satellite is sensitive to n fNL 0.”
• Primordial Non-Gaussianity and Bispectrum Measurements in the Cosmic Microwave Background and Large-Scale Structure (2010, methodology): “[87], while in the study by Taruya et al.”