2015/06/30 by Stefano Gariazzo, Laura Lopez-Honorez, Olga Mena · 1 citation
Physics and Astronomy · #astro-ph.CO
paper · pdf · doi:10.1103/physrevd.92.063510
published as Phys. Rev. D 92, 063510 (2015) · 11 pages, 2 figures
arxiv created 2015/09/10 · arxiv updated 2015/09/11
The simplest models of inflation predict small non-gaussianities and a featureless power spectrum. However, there exist a large number of well-motivated theoretical scenarios in which large non-gaussianties could be generated. In general, in these scenarios the primordial power spectrum will deviate from its standard power law shape. We study, in a model-independent manner, the constraints from future large scale structure surveys on the local non-gaussianity parameter f\rm NL when the standard power law assumption for the primordial power spectrum is relaxed. If the analyses are restricted to the large scale-dependent bias induced in the linear matter power spectrum by non-gaussianites, the errors on the f\rm NL parameter could be increased by 60% when exploiting data from the future DESI survey, if dealing with only one possible dark matter tracer. In the same context, a nontrivial bias |δf\rm NL| ∼ 2.5 could be induced if future data are fitted to the wrong primordial power spectrum. Combining all the possible DESI objects slightly ameliorates the problem, as the forecasted errors on f\rm NL would be degraded by 40% when relaxing the assumptions concerning the primordial power spectrum shape. Also the shift on the non-gaussianity parameter is reduced in this case, |δf\rm NL| ∼ 1.6. The addition of Cosmic Microwave Background priors ensure robust future f\rm NL bounds, as the forecasted errors obtained including these measurements are almost independent on the primordial power spectrum features, and |δf\rm NL| ∼ 0.2, close to the standard single-field slow-roll paradigm prediction.