MeerKAT radio observations of the neutron star low-mass X-ray binary Cen X–4 at low accretion rates

Centaurus X-4 (Cen X-4) is a relatively nearby neutron star low-mass X-ray binary that showed outbursts in 1969 and 1979, but has not shown full outburst since. Due to its proximity sustained period of quiescence, it prime target study the coupling between accretion jet ejection quiescent binaries. Here, we present four MeerKAT radio observations at 1.3 GHz Cen X-4, combined with NICER Swift monitoring. During first most sensitive observation, was fully state. The three later shorter targeted brief faint activity January 2021, which been referred as 'mis-fired' outburst. detected any observations. We place these non-detections on -- luminosity diagram, improving constraints correlation two luminosities from earlier studies. confirm fainter than transitional milli-second pulsar PSR J1023+0038 same luminosity. discuss behaviour accreting stars low more generally finally comment future observing campaigns.