A new look at Anomalous X-ray Pulsars

Abstract

We explore a possibility to explain the phenomenon of the Anomalous X-ray Pulsars (AXP) and Soft Gamma-ray Repeaters (SGR) within the scenario of fall-back magnetic accretion onto a young isolated neutron star. The X-ray emission of the pulsar in this case is originated due to accretion of matter onto the surface of the neutron star from the magnetic slab surrounding its magnetosphere. The expected spin-down rate of the neutron star within this approach is close to the observed value. We show that these neutron stars are relatively young and are going through a transition from the propeller state to the accretor state. The pulsars activity in the gamma-rays is connected with their relative youth and is provided by the energy stored in the non-equilibrium layer located in the crust of low-mass neutron stars. This energy can be released due to mixing of matter in the neutron star crust with super heavy nuclei approaching its surface and getting unstable. The nuclei fission in the low-density region initiates chain reactions leading to the nuclear explosion. The outbursts are likely to be triggered by an instability developing in the region where the matter accreted by the neutron star is accumulated at the magnetic pole regions.

15 pages, Published in Astronomy Reports, Vol. 58, Nr. 4, p. 217 (2014)

References in corpus (11)

• Tests of general relativity from timing the double pulsar
• The strongest cosmic magnets: Soft Gamma-ray Repeaters and Anomalous X-ray Pulsars
• Multi-telescope timing of PSR J1518+4904
• Recent Progress on Anomalous X-ray Pulsars
• Giant Flare in SGR 1806-20 and Its Compton Reflection from the Moon
• Binary and recycled pulsars: 30 years after observational discovery
• Signs of magnetic accretion in young Be/X-ray pulsar SXP 1062
• Burst Fluence Distributions of Soft Gamma Repeaters 1806-20 and 1900+14 in the RXTE PCA era
• Signs of Magnetic Accretion in the X-ray Pulsar Binary GX 301-2
• A new look at the origin of the 6.67\,hr period X-ray pulsar 1E~161348-5055
• Signs of magnetic accretion in X-ray pulsars

Cited by in corpus (7)

• Atmospheres and radiating surfaces of neutron stars
• Neutron stars - thermal emitters
• The Magnetic Field Evolution of ULX NuSTAR J095551+6940.8 in M82--A Legacy of Accreting Magnetar
• A scenario of the formation of isolated X-ray pulsars with anomalously long period
• Young neutron stars with soft gamma ray emission and anomalous X-ray pulsar
• Dynamic model of a non-equilibrium chemical composition formation in the shell of single neutron stars
• About the observational check of the mechanism of gamma radiation in Soft Gamma Repeaters (SGR)