RADIO OBSERVATIONS OF THE NEUTRON STAR X-RAY BINARY CIRCINUS X-1: CLUES ON THE ONSET OF RADIO EMISSION AND JET FORMATION

Circinus X-1 is a Neutron-Star X-ray Binary System which features strong and variable radio emission. This emission is triggered as a result of the interaction between neutron star and its companion as they approach periastron. Radio observations of Circinus X-1 have not been carried out over the past 7 years. Here are the results of the radio observation and monitoring campaign on Circinus X-1 with the Australia Telescope Compact Array (ATCA) – Australia, at centimeter wavelengths (5.5 and 9 GHz). The radio behavior of Circinus X-1 has been monitored over two of its orbits (16.6 days each) to probe its current radio brightness as a function of its orbit. An investigation on whether there is any correlation between the observed radio emission and the estimated accretion rates, and what difference do the orbital phases make in terms of the system’s observed behavior has been made.