Extended Data Fig. 7: The February 2019 simultaneous X-ray/radio campaign.

a, The X-ray 0.4–2 keV Chandra light curve. b–d, The MeerKAT1 (b), VLA (c) and ATCA2 (d) light curves from the simultaneous radio campaign. Notice that the MeerKAT1 and ATCA2 exposures include one X-ray QPE each (vertical shaded areas), whereas the VLA observation was performed during X-ray quiescence. No significant radio variability is detected in any of the radio exposures. The ATCA2 data points are all upper limits, and the horizontal shaded area in d represents the measured time-averaged flux density. We ignore the first data point of the ATCA2 light curve as the source was still very low on the horizon, resulting in a highly degraded image. We also point out that the ATCA2 measurements are contaminated by a nearby unresolved radio source detected by the VLA with a flux density of 71 ± 10 μJy at 6 GHz. Error bars, including the average flux from ATCA (horizontal shaded area in d) represent the 1σ confidence intervals. The ATCA data points (d) are instead 3σ confidence level upper limits.