Modelling the multiband spectrum of IGR J17177−3656




The correlation between radio and X-ray luminosity in the hard state of black hole X-ray binaries is important for unveiling the relation between the accretion flow and the jets. In this Letter, we have modelled the quasi-simultaneous multiband observations of a recently discovered transient X-ray source, IGR J17177−3656. It is found that the source is probably an outlier following the steep radio/X-ray correlation rather than an outlier in the transition region as suggested by Paizis et al. It is also found that the multiband spectrum can be successfully modelled by the luminous hot accretion flow (LHAF) but less likely by the advection dominated accretion flow. Our results support the point that LHAF can explain the steep radio/X-ray correlation.