Accretion mode of the Ultra-Luminous X-ray source M82 X-2

Abstract

Periodic pulsations have been found in emission from the ultra-luminous X-ray source (ULX) M82 X-2, strongly suggesting that the emitter is a rotating neutron star rather than a black hole. However, the radiation mechanisms and accretion mode involved have not yet been clearly established. In this paper, we examine the applicability to this object of standard accretion modes for high mass X-ray binaries (HMXBs). We find that spherical wind accretion, which drives OB-type HMXBs, cannot apply here but that there is a natural explanation in terms of an extension of the picture for standard Be-type HMXBs. We show that a neutron star with a moderately strong magnetic field, accreting from a disc-shaped wind emitted by a Be-companion, could be compatible with the observed relation between spin and orbital period. A Roche lobe overflow picture is also possible under certain conditions.

8 pages, 5 figures, accepted for publication in MNRAS

References in corpus (13)

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• Bimodality of Wind-fed Accretion in High Mass X-ray Binaries
• Super-Eddington accretion in ultra-luminous neutron star binary

Cited by in corpus (11)

• Formation of Double Neutron Star Systems
• A ~60-day super-orbital period originating from the ultraluminous X-ray pulsar in M82
• SWIFT Detection of a 65-Day X-ray Period from the Ultraluminous Pulsar NGC 7793 P13
• On the possibility of disk-fed formation in supergiant high-mass X-ray binaries
• A Population of Neutron Star Ultraluminous X-ray Sources with A Helium Star Companion
• Constraining the dipolar magnetic field of M82 X-2 by the accretion model
• High Energy Gamma Rays from Nebulae Associated with Extragalactic Microquasars and Ultra-Luminous X-ray Sources
• High-Mass X-Ray Binaries with Be Donors as Ultraluminous X-Ray Sources
• Characteristics and evolution of Be-type high mass X-ray binaries as potential Ultraluminous X-ray Sources
• Nature of donors in ultra-luminous X-ray binaries powered by neutron stars
• A possible origin of the Galactic Center magnetar SGR 1745-2900