THEORETICAL EXPECTATIONS FOR BULK FLOWS IN LARGE-SCALE SURVEYS

We calculate the theoretical expectation for the bulk motion of a larg e-scale survey of the type recently carried out by Lauer and Postman. Included are the effects of survey geometry, errors in the distance me asurements, clustering properties of the sample, and different assumed power spectra. We consider the power spectrum calculated from the IRA S-QDOT survey, as well as spectra from hot + cold and standard cold da rk matter models. We find that measurement uncertainty, sparse samplin g, and clustering can lead to a much larger expectation for the bulk m otion of a cluster sample than for the volume as a whole. However, our results suggest that the expected bulk motion is still inconsistent w ith that reported by Lauer and Postman at the 95%-97% confidence level .