VLBI detection of the AE Aqr twin, LAMOST J024048.51+195226.9
Journal article, 2024
LAMOST J024048.51+195226.9 (J0240+1952) was recently identified as the second AE Aquarii (AE Aqr)-type cataclysmic variable, possessing the fastest known rotating white dwarf. We performed a Very Long Baseline Interferometry (VLBI) observation of J0240+1952 utilizing the European VLBI Network at 1.7 GHz, to obtain the first view of the radio morphology on mas scale. Our high-resolution VLBI image clearly shows that the radio emission is compact on mas scale (≲2 AU), with no evidence for a radio jet or extended emission. The compact radio source has an average flux density of ∼0.37 mJy, and its brightness temperature is given at ∼2.3 × 107 K, confirming a non-thermal origin. The emission exhibits irregular variations on a time-scale of tens of minutes, similar to the radio flares seen in AE Aqr. The measured VLBI position of J0240+1952 is consistent with that derived from Gaia. Our results favour the model in which the radio emission is attributed to a superposition of synchrotron radiation from expanding magnetized blobs of this system.
stars: magnetic field
white dwarfs
techniques: high angular resolution
radio continuum: stars
Author
Pengfei Jiang
Xinjiang Astronomical Observatory
Chinese Academy of Sciences
Lang Cui
Xinjiang Key Laboratory of Radio Astrophysics
Xinjiang Astronomical Observatory
Chinese Academy of Sciences
Xiang Liu
Xinjiang Key Laboratory of Radio Astrophysics
Chinese Academy of Sciences
Xinjiang Astronomical Observatory
Bo Zhang
Shanghai Astronomical Observatory
Yongfeng Huang
Nanjing University
Hong Min Cao
Shangqiu Normal University
T. An
Shanghai Astronomical Observatory
Xinjiang Astronomical Observatory
Jun Yang
Chalmers, Space, Earth and Environment, Onsala Space Observatory
Fengchun Shu
Shanghai Astronomical Observatory
Guiping Tan
Xinjiang Astronomical Observatory
Jianping Yuan
Xinjiang Astronomical Observatory
Monthly Notices of the Royal Astronomical Society: Letters
17453925 (ISSN) 17453933 (eISSN)
Vol. 528 1 L112-L116Subject Categories
Astronomy, Astrophysics and Cosmology
Fusion, Plasma and Space Physics
DOI
10.1093/mnrasl/slad178