A spectroscopic, photometric, polarimetric, and radio study of the eclipsing polar UZ Fornacis: the first simultaneous SALT and MeerKAT observations. Issue 3 (11th January 2020)

• Record Type: Journal Article
• Authors: Khangale, Z N; Potter, S B; Woudt, P A; Buckley, D A H; Semena, A N; Kotze, E J; Groenewald, D N; Hewitt, D M; Pretorius, M L; Fender, R P; Groot, P; Bloemen, S; Klein-Wolt, M; Körding, E; Le Poole, R; McBride, V A; Townsend, L; Paterson, K; Pieterse, D L A; Vreeswijk, P
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 492:Issue 3(2020)
• Page Start: 4298
• Page End: 4312
• Publication Date: 2020-01-11
• Subjects: accretion, accretion discs -- binaries: close -- stars: individual: UZ For -- stars: magnetic fields -- novae, cataclysmic variables -- white dwarfs; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/staa080
• Languages: English
• ISSNs: 0035-8711

Abstract

ABSTRACT: We present phase-resolved spectroscopy, photometry, and circular spectropolarimetry of the eclipsing polar UZ Fornacis. Doppler tomography of the strongest emission lines using the inside-out projection revealed the presence of three emission regions: from the irradiated face of the secondary star, the ballistic stream and the threading region, and the magnetically confined accretion stream. The total intensity spectrum shows broad emission features and a continuum that rises in the blue. The circularly polarized spectrum shows the presence of three cyclotron emission harmonics at ∼4500, 6000, and 7700 Å, corresponding to harmonic numbers 4, 3, and 2, respectively. These features are dominant before the eclipse and disappear after the eclipse. The harmonics are consistent with a magnetic field strength of ∼57 MG. We also present phase-resolved circular and linear photopolarimetry to complement the spectropolarimetry around the times of eclipse. MeerKAT radio observations show a faint source that has a peak flux density of 30.7 ± 5.4 $\mu$ Jy beam −1 at 1.28 GHz at the position of UZ For.