Presentation #110.33 in the session “Stellar/Compact (Poster)”.
X-ray binaries (XRBs) are known to produce radio jets, whose connection with the accretion flow has been well studied over the past two decades. Optically thick, flat-spectrum, compact steady jets are observed during the hard X-ray spectral state, whereas steep-spectrum, relativistically-moving transient jets are detected near the peak of the outburst, when the source undergoes a transition from the hard to the soft X-ray spectral state XRBs allow us to study the connection between inflow and outflow around a black hole on humanly observable timescales. Despite a wealth of higher-frequency observations over the past few decades, XRBs remain relatively poorly studied at frequencies below 500 MHz. We are using the Murchison Widefield Array (MWA), the Australian Square Kilometre Array Pathfinder (ASKAP) and MeerKAT to characterize the properties of XRB jets in the low-frequency band. Low-frequency observations of steady, low-luminosity jets can constrain the distance out to which energy dissipation occurs. Simultaneous high-cadence radio monitoring of XRB outbursts across a broad range of radio frequencies can constrain important physical properties of the jets including the distance, the magnetic field strength, the equipartition energy, and the jet opening angle. In this talk, I will present the low-frequency observations of three black hole candidate X-ray binaries. Using HI absorption towards MAXI J1535-571 with ASKAP, and towards MAXI J1348-630 with both ASKAP and MeerKAT, we determined the kinematic distances of these sources. Combining broadband radio coverage with high angular resolution imaging, we determined the jet opening angle, magnetic field strength and minimum energy for MAXI J1535-571. With the MWA, we made the first low-frequency detections of steady low-luminosity jets in both MAXI J1820+070 and MAXI J1348-630. I will conclude by outlining the potential of the upcoming low-frequency radio interferometers for understanding the key physical properties of XRBs and their jets.