Multi-wavelength study of the eclipsing polar UZ Fornacis

Abstract

We present phase-resolved spectroscopy and circular spectropolarimetry of the eclipsing polar UZ Fornacis. Doppler tomography of the strongest features (Hβ line) using the inside-out technique revealed the presence of three emission regions: from the irradiated face of the secondary star, the ballistic stream and the threading region, and the magnetic confined accretion stream. The total intensity spectrum shows broad emission features that span the entire bandwidths with the continuum that rises in the blue. The circularly polarized spectrum shows the presence of three cyclotron harmonics at 4500 Å, 6000 Å and 7700 Å, corresponding to harmonic numbers 4, 3, and 2, respectively. These features are dominant before the eclipse and disappears after the eclipse. The harmonics are consistent with the magnetic field strength of ∼57 MG. We also present phaseresolved circular and linear photopolarimetry to complement the spectro-polarimetry around the times of eclipse. Our current MeerKAT observations show a faint source which has a peak flux density of 31 ± 6 µJy per beam at a position of UZ For. We place the formal upper limit of ∼37 µJy per beam at 1.28 GHz.