VAND-TH-97-03 AZPH-TH/97-04 An Attempt to Determine the Largest Scale of Primordial Density Perturbations in the Universe
نویسندگان
چکیده
Causality constraints require a super-Hubble scale suppression in the primordial power spectrum. This modification is implemented and a three parameter likelihood analysis is performed of the COBE-DMR 4-year data with respect to the amplitude, spectral index, and suppression scale. All suppression length scales larger than c/H0 are consistent with the data, but scales of order 4c/H0 are slightly preferred, at roughly the one-sigma level. Many non-inflation models would be consistent with a small suppression length scale, whereas for standard inflation models, it would require small e-folds. Suppression scales smaller than c/H0 are strongly excluded by the anisotropy data. PACS numbers: 98.80.Es
منابع مشابه
ar X iv : a st ro - p h / 94 01 02 3 v 1 1 4 Ja n 19 94 AZPH - TH / 93 - 5 Stochastic Fluctuations and Structure Formation in the Universe
It is shown that the evolution of the density perturbations during certain eras of substantial entropy generation in the universe can be described in the scheme of the KPZ equation. Therefore, the influence on cosmological structure formation by stochastic forces arising from various dissipations can be studied through the universal characteristics of surface growth in d = 3 + 1 dimensions. We ...
متن کاملModular thermal inflation without slow-roll approximation
We study an inflationary scenario where thermal inflation is followed by fast-roll inflation. This is a rather generic possibility based on the effective potentials of spontaneous symmetry breaking in the context of particle physics models. We show that a large enough expansion could be achieved to solve cosmological problems. However, the power spectrum of primordial density perturbations from...
متن کاملTwo-Stage Inflation as a Solution to the Initial Condition Problem of Hybrid Inflation
We address the issue of fine-tuning of the initial field configuration that can lead to hybrid inflation in the context of global supersymmetry. This problem is generated by the difference between the energy scale at which the Universe emerges from the Planck era and the inflationary scale implied by the COBE observations: V 1/4 ∼ 10−3mPl. We propose a scenario with two stages of inflation. The...
متن کاملX iv : a st ro - p h / 97 03 08 8 v 1 1 3 M ar 1 99 7 Large - scale tidal fields on primordial density peaks ? . II Alignment of cosmic structures
We show that the primordial density field imposes certain degree of coherence in the orientation of density perturbations. We quantify the scale of coherence and show that is significant on scales of at least 30 − 40h −1 Mpc, being more important in density fields with flat spectrum. Evidence is also presented that the reason for this coherence is that the long density waves are the dominant pa...
متن کاملar X iv : a st ro - p h / 97 04 25 4 v 1 2 5 A pr 1 99 7 Upper limit to Ω B in scalar - tensor gravity theories
In a previous paper (Serna & Alimi 1996b), we have pointed out the existence of some particular scalar-tensor gravity theories able to relax the nucleosynthesis constraint on the cosmic baryonic density. In this paper, we present an exhaustive study of primordial nucleosynthesis in the framework of such theories taking into account the currently adopted observational constraints. We show that a...
متن کامل