Radio Detections of Ultraluminous X-ray Sources

We present some results from an archival VLA study of ultraluminous X-ray source s (ULXs). These unresolved non-nuclear X-ray sources have luminosities (L_X >= 1 0^39 ergs/sec) which may require somewhat exotic explanations, such as intermedi ate mass black holes or super-Eddington accretion. Radio emission is a powerful way to investigate such sources, through radio morphology and the implications m ade by source energy and lifetimes derived from the radio. The three galaxies we present here suggest that no single model explains all ULXs, yet there is growi ng evidence that some ULXs are powered by intermediate mass black holes.