Speaker
Description
Multi-wavelength observations are essential to understand the coupling between the accretion flow and the jet in black hole X-ray binary (BHXRB). We investigate the X-ray and radio emissions in MAXI J1348-630 during its 2019 outburst. For the first time, we find that the radio emission lags behind the X-ray Comptonization emission by about 3 days during the rising phase covering the rising hard state and the following soft state. Such a long radio delay indicates that, in this source, the Comptonization emission most likely originates from the advection-dominated accretion flow (ADAF) rather than the jet during the rising phase. Further, we study the correlation between the X-ray Comptonization and radio emissions in a broad X-ray energy band 0.1-100 keV. During the rising phase, considering the radio delay of ~ 3 days, we obtain a slope β = 3.04 ± 0.93, which is much steeper than the previously reported β = 0.6 or 1.40 using the total luminosity in the limited band (e.g., 1-10 keV). During the mini-outburst, the radio-Compton correlation becomes shallow with the correlation slope β = 1.11±0.15. These indicate an intrinsic difference in the accretion-jet coupling physics between the main outburst and the mini-outburst.
