Limits on the gravity wave contribution to microwave anisotropies

We present limits on the fraction of large angle microwave anisotropies which could come from tensor perturbations. We use the COBE results as well as smaller scale CMB observations, measurements of galaxy correlations, abundances of galaxy clusters, and Lyα absorption cloud statistics. Our aim is to provide conservative limits on the tensor-to-scalar ratio for standard inflationary models. For power-law inflation, for example, we find T/S < 0.52 at 95% confidence, with a similar constraint for φp potentials. However, for models with tensor amplitude unrelated to the scalar spectral index it is still currently possible to have T/S > 1. PACS numbers: 98.80.-k, 98.70.Vc. Typeset using REVTEX