Ultraluminous x-ray sources
definition: An X-ray source that is not in the nucleus of a galaxy, and is more luminous than 10^39 ergs s^-1, brighter than the Eddington luminosity of a 10 solar mass black hole. In general, there is about one ULX per galaxy in galaxies which host ULXs. The Milky Way contains no such objects. ULXs are thought to be powered by accretion onto a compact object. Possible explanations include accretion onto neutron stars with strong magnetic fields, onto stellar black holes (of up to 20 solar masses) at or in excess of the classical Eddington limit, or onto intermediate-mass black holes (10^3 - 10^5 solar masses). NGC 1313X-1, NGC 5408X-1, and NGC 6946X-1 are three ULXs with X-ray luminosities up to ~10^40 erg s^-1.
alternative label: SSS
alternative label: Pulsating ultraluminous X-ray sources
alternative label: Ultraluminous supersoft sources
alternative label: Luminous supersoft x-ray source
alternative label: Supersoft sources
alternative label: ULX
alternative label: PULX
alternative label: ULS
alternative label: SSXS
created: 2020-09-11T18:11:37.156Z
modified: 2020-11-04T21:41:16.938Z
modified: 2020-11-04T21:41:03.492Z
creator: AAS Frey.Katie
type: Concept
broader: X-ray sources
contributor: AAS Frey.Katie Admin

X-ray sources
type: Concept
narrower: Ultraluminous x-ray sources