CORONGIU, ALESSANDROALESSANDROCORONGIUMignani, R. P.R. P.MignaniSeyffert, A. S.A. S.SeyffertClark, C. J.C. J.ClarkVenter, C.C.VenterNieder, L.L.NiederPOSSENTI, ANDREAANDREAPOSSENTIBURGAY, MARTAMARTABURGAYBelfiore, A.A.BelfioreDE LUCA, AndreaAndreaDE LUCARIDOLFI, ALESSANDROALESSANDRORIDOLFIWadiasingh, Z.Z.Wadiasingh2022-03-172022-03-1720210035-8711http://hdl.handle.net/20.500.12386/31671The predicted nature of the candidate redback pulsar 3FGL J2039.6-5618 was recently confirmed by the discovery of γ-ray millisecond pulsations (Clark et al., hereafter Paper I), which identify this γ-ray source as PSR J2039-5617. We observed this object with the Parkes radio telescope in 2016 and 2019. We detect radio pulsations at 1.4 and 3.1 GHz, at the 2.6 ms period discovered in γ-rays, and also at 0.7 GHz in one 2015 archival observation. In all bands, the radio pulse profile is characterized by a single relatively broad peak which leads the main γ-ray peak. At 1.4 GHz, we found clear evidence of eclipses of the radio signal for about half of the orbit, a characteristic phenomenon in redback systems, which we associate with the presence of intra-binary gas. From the dispersion measure of 24.57 ± 0.03 pc cm<SUP>-3</SUP>, we derive a pulsar distance of 0.9 ± 0.2 or 1.7 ± 0.7 kpc, depending on the assumed Galactic electron density model. The modelling of the radio and γ-ray light curves leads to an independent determination of the orbital inclination, and to a determination of the pulsar mass, qualitatively consistent to the results in Paper I.STAMPAenArticle10.1093/mnras/staa34632-s2.0-85103251032http://arxiv.org/abs/2007.14889v2https://academic.oup.com/mnras/article/502/1/935/59990732021MNRAS.502..935CFIS/05 - ASTRONOMIA E ASTROFISICA