2022MNRAS.516.5148H

The connection of type-B quasi-periodic oscillations (QPOs) to the hot flow in the inner accretion disc region is vaguely understood in black hole X-ray binaries. We performed spectral and timing studies of 23 observations where type-C and type-B QPOs with similar centroid frequencies (∼6 Hz) occurred. Their spectral differences were used to understand the production mechanism of type-B QPOs, along with the quasi-simultaneous radio observations. Based on the spectral results, we did not notice many variations in the Comptonization parameters and the inner disc radius during type-C and type-B QPOs. We found that the structure of the Comptonization region has to be different for observations associated with type-C and type-B QPOs based on the CompTT model. Radio flux density versus QPO width, soft to hard flux ratio, and QPO width versus inner disc temperature, were found to follow certain trends, suggesting that a jet could be responsible for the type-B QPOs in H1743-322. Further studies are required to uniquely constrain this scenario. In a case study where a gradual transition from type-C to type-B QPO was noticed, we found that the spectral changes could be explained by the presence of a jet or a vertically extended optically thick Comptonization region. The geometrical Lense-Thirring precession model with a hot flow and a jet in the inner region was incorporated to explain the spectral and timing variations.