We evaluate and compare the gravitational wave and density perturbation contributions to the cosmic microwave background radiation , on the basis of the same power law inflationary model .
The inflation to radiation transition is treated in this paper as instantaneous , but a model is constructed to allow for a smooth transition from the radiation to the matter dominated eras .
The equations are numerically investigated and integrated , without any basic approximations being made .
Use is made of the synchronous gauge , with appropriate gauge invariant variables , thus eliminating any confusion arising from unphysical gauge modes .
We find a non- negligible gravitational wave contribution , which becomes dominant for a power law expansion with exponent q < 13 .
We also explore the dependence of our results with the main characteristic of the transition region , its length .