TY - JOUR
T1 - Simulations of the magnetospheres of accreting millisecond pulsars
AU - Parfrey, Kyle
AU - Spitkovsky, Anatoly
AU - Beloborodov, Andrei M.
N1 - Funding Information:
KP was supported by the Max Planck-Princeton Center for Plasma Physics and by NASA through Einstein Postdoctoral Fellowship grant number PF5-160142 awarded by the Chandra X-ray Center, which is operated by the Smithsonian Astrophysical Observatory for NASA under contract NAS8-03060. AS acknowledges support from NASA grants NNX14AQ67G, NNX15AM30G and a Simons Investigator Award from the Simons Foundation. AMB acknowledges support from NASA grant NNX13AI34G and a Simons Investigator Award from the Simons Foundation. The simulations presented in this paper were performed on computational resources supported by the Princeton Institute for Computational Science and Engineering (PICSciE) and the Office of Information Technology's High Performance Computing Center and Visualization Laboratory at Princeton University, and on the SAVIO computational cluster resource provided by the Berkeley Research Computing programme at the University of California, Berkeley (supported by the UC Berkeley Chancellor, Vice Chancellor of Research and Office of the CIO).
Funding Information:
KP was supported by the Max Planck-Princeton Center for Plasma Physics and by NASA through Einstein Postdoctoral Fellowship grant number PF5-160142 awarded by the Chandra X-ray Center, which is operated by the Smithsonian Astrophysical Observatory for NASA under contract NAS8-03060. AS acknowledges support from NASA grants NNX14AQ67G, NNX15AM30G and a Simons Investigator Award from the Simons Foundation. AMB acknowledges support from NASA grant NNX13AI34G and a Simons Investigator Award from the Simons Foundation.
Funding Information:
The simulations presented in this paper were performed on computational resources supported by the Princeton Institute for Computational Science and Engineering (PICSciE) and the Office of Information Technology’s High Performance Computing Center and Visualization Laboratory at Princeton University, and on the SAVIO computational cluster resource provided by the Berkeley Research Computing programme at the University of California, Berkeley (supported by the UC Berkeley Chancellor, Vice Chancellor of Research and Office of the CIO).
Publisher Copyright:
© 2017 The Authors.
PY - 2017/8/11
Y1 - 2017/8/11
N2 - Accreting pulsars power relativistic jets and display a complex spin phenomenology. These behaviours may be closely related to the large-scale configuration of the star's magnetic field, shaped by its interaction with the surrounding accretion disc. Here, we present the first relativistic simulations of the interaction of a pulsar magnetosphere with an accretion flow. Our axisymmetric simulations treat the magnetospheric, or coronal, regions using a resistive extension of force-free electrodynamics. The magnetic field is also evolved inside the disc, which is a defined volume with a specified velocity field and conductivity profile, found using an α-disc model. We study a range of disc αparameters, thicknesses, magnetic Prandtl numbers and inner truncation radii. We find that a large fraction of the magnetic flux in the pulsar's closed zone is opened by the intrusion of the disc, leading to an enhancement of the power extracted by the pulsar wind and the spin-down torque applied to the pulsar. In our simulations, most of the spin-down contribution to the stellar torque acts on open field lines. The efficiency of field-line opening is high in the simulations' long-term quasi-steady states, which implies that a millisecond pulsar's electromagnetic wind could be strong enough to power the observed neutron-star radio jets, and may significantly affect the pulsar's spin evolution.
AB - Accreting pulsars power relativistic jets and display a complex spin phenomenology. These behaviours may be closely related to the large-scale configuration of the star's magnetic field, shaped by its interaction with the surrounding accretion disc. Here, we present the first relativistic simulations of the interaction of a pulsar magnetosphere with an accretion flow. Our axisymmetric simulations treat the magnetospheric, or coronal, regions using a resistive extension of force-free electrodynamics. The magnetic field is also evolved inside the disc, which is a defined volume with a specified velocity field and conductivity profile, found using an α-disc model. We study a range of disc αparameters, thicknesses, magnetic Prandtl numbers and inner truncation radii. We find that a large fraction of the magnetic flux in the pulsar's closed zone is opened by the intrusion of the disc, leading to an enhancement of the power extracted by the pulsar wind and the spin-down torque applied to the pulsar. In our simulations, most of the spin-down contribution to the stellar torque acts on open field lines. The efficiency of field-line opening is high in the simulations' long-term quasi-steady states, which implies that a millisecond pulsar's electromagnetic wind could be strong enough to power the observed neutron-star radio jets, and may significantly affect the pulsar's spin evolution.
KW - Accretion
KW - Accretion discs
KW - Magnetic fields
KW - Pulsars: general
KW - Stars: neutron
KW - X-rays: binaries
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U2 - 10.1093/mnras/stx950
DO - 10.1093/mnras/stx950
M3 - Article
AN - SCOPUS:85023782421
SN - 0035-8711
VL - 469
SP - 3656
EP - 3669
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 3
ER -