Probing X-ray emission in different modes of PSR J1023+0038 with a radio pulsar scenario

Abstract

Transitional pulsars provide us with a unique laboratory to study the physics of accretion onto a magnetic neutron star. PSR J1023+0038 (J1023) is the best studied of this class. We investigate the X-ray spectral properties of J1023 in the framework of a working radio pulsar during the active state. We modelled the X-ray spectra in three modes (low, high, and flare) as well as in quiescence, to constrain the emission mechanism and source parameters. The emission model, formed by an assumed pulsar emission (thermal and magnetospheric) plus a shock component, can account for the data only adding a hot dense absorber covering ~30% of the emitting source in high mode. The covering fraction is similar in flaring mode, thus excluding total enshrouding, and decreases in the low mode despite large uncertainties. This provides support to the recently advanced idea of a mini-pulsar wind nebula (PWN), where X-ray and optical pulsations arise via synchrotron shock emission in a very close (~100 km, comparable to a light cylinder), PWN-like region that is associated with this hot absorber. In low mode, this region may expand, pulsations become undetectable, and the covering fraction decreases.

arXiv commentAccepted in A&A Letter. 5 pages, 1 figure

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Cited by in corpus (14)

• Transitional millisecond pulsars
• Matter ejections behind the highs and lows of the transitional millisecond pulsar PSR J1023+0038
• Optical and ultraviolet pulsed emission from an accreting millisecond pulsar
• Investigating the origin of optical and X-ray pulsations of the transitional millisecond pulsar PSR J1023+0038
• UV and X-ray pulse amplitude variability in the transitional millisecond pulsar PSR J1023+0038
• Multiwavelength evidence for a new flare-mode transitional millisecond pulsar
• NuSTAR and Parkes observations of the transitional millisecond pulsar binary XSS J12270-4859 in the rotation-powered state
• Simultaneous X-ray and radio observations of the transitional millisecond pulsar candidate CXOU J110926.4-650224. The discovery of a variable radio counterpart
• Spin-down rate of the transitional millisecond pulsar PSR J1023+0038 in the optical band with Aqueye+
• X-ray study of high-and-low luminosity modes and peculiar low-soft-and-hard activity in the transitional pulsar XSS J12270-4859
• Polarized multiwavelength emission from pulsar wind - accretion disk interaction in a transitional millisecond pulsar
• Probing multi-band variability and mode switching in the candidate transitional millisecond pulsar 3FGL J1544.6-1125
• Measuring accretion disc properties in the transitional millisecond pulsar PSR J1023+0038 using XMM-Newton, NuSTAR, NICER and Chandra
• There and back again: Mysterious optical pulse profile behavior of the transitional millisecond pulsar PSR J1023+0038