NASA/CXC/Caltech/M. Brightman et al.

Ultraluminous X-ray Sources

Ultraluminous X-ray Sources (ULXs) provide a unique opportunity to study super-Eddington accretion in the nearby universe. The nature of these luminous, off-nuclear point sources has long been debated, with some claims that they were the elusive intermediate-mass black holes accreting at sub-Eddington rates, and others that they represent a population of stellar mass compact objects accreting at high rates. With the discovery of pulsations in several ULXs, it is now clear that it is possible, at least for neutron stars, to produce emission that appears up to 500 times the theoretical limit for accretion, known as the Eddington limit.

Recent Papers:

• Kara et al., 2019. Discovery of a soft X-ray lag in the Ultraluminous X-ray Source NGC 1313 X-1. MNRAS, in press.