Radio and X-ray luminosities of accreting BHs and NSs. The quasi-simultaneous radio and X-ray luminosities of J0840 during quiescence are shown using the red square and orange diamond for the assumed distances of 5 and 10 kpc, respectively. We show the population of BH–LMXBs (black circles), NS–LMXBs (blue squares), and accreting millisecond X-ray pulsars (AMXPs; green triangles). The grey dashed line indicates the best-fit correlation for the BH systems from Gallo et al. (2018). Our radio and X-ray observations of J0840 do not differentiate between a BH or NS accretor. Data taken from Bahramian et al. (2018).