Abstract
We consider the primordial gravitational wave (GW) background in a class of spatially flat inflationary cosmological models with cold dark matter (CDM), a cosmological constant, and a broken scale-invariant (BSI) step-like primordial (initial) spectrum of adiabatic perturbations produced in an exactly solvable inflationary model where the inflaton potential has a rapid change of its first derivative at some point. In contrast to inflationary models with a scale-free initial spectrum, these models may have a GW power spectrum the amplitude (although not the shape) of which is arbitrary for fixed amplitude and shape of the adiabatic perturbation power spectrum. In the presence of a positive cosmological constant, the models investigated here possess the striking property that a significant part of the large-angle cosmic microwave background (CMB) temperature anisotropy observed in the COBE experiment is a result of primordial GW. Confronting the models with existing observational data on CMB angular temperature fluctuations, galaxy clustering and peculiar velocities of galaxies, we find that, for the best parameter values ΩΛ≈0.7 and h≈0.7, the GW contribution to the CMB anisotropy can be as large as that of the scalar fluctuations.
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
