| Name: | Broja G Dutta |
| Affiliation: | Department of Physics, RBC College, West Bengal State University |
| Conference ID : | ASI2024_828 |
| Title : | Origin of Soft/Hard X-ray Time Lags in Black Hole Transients and Bare-Type AGN |
| Authors : | Broja G. Dutta1, Soumen Mondal2 |
| Authors Affiliation: | 1. Broja G. Dutta (Department of Physics, RBC College, Naihati, North 24 Parganas, W.B, PIN 743165)
2. Soumen Mondal (S.N. Bose National Centre for Basic Sciences, JD-Block, Saltlake, Kolkata 700098) |
| Mode of Presentation: | Oral |
| Abstract Category : | High Energy Phenomena, Fundamental Physics and Astronomy |
| Abstract : | The complex nature of time lag properties in Black Hole Transients depends on the source's inclination and involves multiple non-linear mechanisms. The systematic increase in the frequency of type-C Quasi-Periodic Oscillations (QPOs) is independent of the source's inclination and implies a gradual decrease in the corona radius during the onset phases of the outburst. Conversely, in the declining state, a systematic decrease in QPO frequency determines a gradual rise in the corona radius. We have studied a long-term, energy-dependent variability properties in bare-type Active Galactic Nuclei (AGN) and various Galactic Black Hole Binaries (GBHBs) using data from RXTE, XMM-Newton, Suzaku, Swift, NuSTAR, and AstroSat observations. We find that the sign of time lag changes at the transition frequency when both accretion rate and disk geometry vary in both types of sources. The changes in the accretion geometry at a specific radius of the corona lead to change in the dominant physical mechanisms governing the accretion dynamics. We have concluded that the origin of time lag/delays could be satisfactorily explained by considering the physical mechanisms such as Comptonization, reflection, accretion geometry, focusing due to gravitational bending, and the effect of disk-jet connections for both the Galactic black hole binaries and bare-type AGN sources. |
