Ultraluminous X-Ray Sources
Abstract
We review observations of ultraluminous X-ray sources (ULXs). X-ray spectroscopic and timing studies of ULXs suggest a new accretion state distinct from those seen in Galactic stellar-mass black hole binaries. The detection of coherent pulsations indicates the presence of neutron-star accretors in three ULXs and therefore apparently super-Eddington luminosities. Optical and X-ray line profiles of ULXs and the properties of associated radio and optical nebulae suggest that ULXs produce powerful outflows, also indicative of super-Eddington accretion. We discuss models of super-Eddington accretion and their relation to the observed behaviors of ULXs. We review the evidence for intermediate mass black holes in ULXs. We consider the implications of ULXs for super-Eddington accretion in active galactic nuclei, heating of the early universe, and the origin of the black hole binary recently detected via gravitational waves.
Cite
@article{arxiv.1703.10728,
title = {Ultraluminous X-Ray Sources},
author = {Philip Kaaret and Hua Feng and Timothy P. Roberts},
journal= {arXiv preprint arXiv:1703.10728},
year = {2017}
}
Comments
38 pages, to appear in Annual Reviews of Astronomy and Astrophysics