An Upper Limit on the Granularity of the Local Stellar Halo

Abstract

I use the statistical properties of 4588 nearby halo stars to show that if the local stellar halo is composed of cold streams from disrupted dwarf satellites as is predicted by popular cosmologies, then at 95% confidence there are at least 1350 such streams. Moreover, no stream can contain more than 2.3% of the local stars, while average streams must contain less than 0.08%.