On the spin-down mechanism of the X-ray pulsar 4U 2206+54

Abstract

Observations of the X-ray pulsar 4U 2206+54, performed over a 15-year span, show its period, which is now 5555 \pm 9 s, to increase drastically. Such behavior of the pulsar can be hardly explained in the frame of traditional scenarios of spin evolution of compact stars. The observed spin-down rate of the neutron star in 4U 2206+54 proves to be in good agreement with the value expected within magnetic accretion scenario which takes into account that magnetic field of the accretion stream can under certain conditions affect its geometry and type of flow. The neutron star in this case accretes material from a dense gaseous slab with small angular momentum which is kept in equilibrium by the magnetic field of the flow itself. The magnetic accretion scenario can be realized in 4U 2206+54 provided the magnetic field strength on the surface of the optical counterpart to the neutron star is in excess of 70 G. The magnetic field strength on the surface of the neutron star in the frame of this scenario turns out to be 4 x 10^{12} G which is in accordance with estimates of this parameter from the analysis of X-ray spectra of the pulsar.

accepted for publication in Astronomy Reports, V.57, March 2013

References in corpus (5)

• Swift/BAT and RXTE Observations of the Peculiar X-ray Binary 4U 2206+54 - Disappearance of the 9.6 Day Modulation
• The origin of long-period X-ray pulsars
• Protoneutron star dynamos: pulsars, magnetars, and radio-silent X-ray emitting neutron stars
• Discovery of slow X-ray pulsations in the high-mass X-ray binary 4U 2206+54
• Three-Dimensional Simulations of Spherical Accretion Flows with Small-Scale Magnetic Fields

Cited by in corpus (7)

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• XMM-Newton spectroscopy of the accreting magnetar candidate 4U0114+65
• Deep Chandra Survey of the Small Magellanic Cloud. II. Timing Analysis of X-ray Pulsars
• Cyclical accretion regime change in the slow X-ray pulsar 4U 0114+65 observed with Chandra
• On the origin of super-global spin-up trends of X-ray pulsars in HMXB systems
• MAD-Accretion Scenario in High-Mass X-Ray Binaries with Neutron Stars
• Monte-Carlo simulations on possible collimation effects of outflows to fan-beamed emission of ultraluminous accreting X-ray pulsars