VLBI Astrometry on the White Dwarf Pulsar AR Scorpii

Jiang, Pengfei
Cui, Lang
Yang, Jun
Zhang, Bo
Xu, Shuangjing
Shu, Fengchun
Jiang, Wu
Chen, Wen
Li, Guanghui
Xia, Bo
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Journal Article
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Oxford University Press (OUP)

jats:pAR Scorpii (AR Sco), the only-known radio-pulsing white dwarf binary, shows unusual pulsating emission at the radio, infrared, optical, and ultraviolet bands. To determine its astrometric parameters at the radio band independently, we conducted multi-epoch Very Long Baseline Interferometry (VLBI) phase-referencing observations with the European VLBI Network at 5 GHz and the Chinese VLBI Network plus the Warkworth 30-m telescope (New Zealand) at 8.6 GHz. By using the differential VLBI astrometry, we provide high-precision astrometric measurements on the parallax ( mas) and proper motion ( mas yr−1,  mas yr−1). The new VLBI results agree with the optical Gaia astrometry. Our kinematic analysis reveals that the Galactic space velocities of AR Sco are quite consistent with that of both intermediate polars and polars. Combined with the previous tightest VLBI constraint on the size, our parallax distance suggests that the radio emission of AR Sco should be located within the light cylinder of its white dwarf.</jats:p>

5101 Astronomical Sciences , 51 Physical Sciences , 0201 Astronomical and Space Sciences , Astronomy & Astrophysics , 5101 Astronomical sciences , 5107 Particle and high energy physics , 5109 Space sciences
Monthly Notices of the Royal Astronomical Society, ISSN: 0035-8711 (Print); 1365-2966 (Online), Oxford University Press (OUP), 520(2), 2942-2951. doi: 10.1093/mnras/stad327
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This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society Published by Oxford University Press on behalf of the Royal Astronomical Society.