Hard state manifestations of galactic black holes

Official URL: http://risc01.sabanciuniv.edu/record=b1534380 (Table of Contents)

This thesis is aimed at understanding the accretion-ejection processes and the physical environment in the vicinity of the Galactic black hole transients (GBHT) in the hard state. In this context, X-ray spectral and temporal, optical/infrared (OIR) photometric and radio properties of GBHTs during the outburst decay are examined. As part of developing analysis techniques for this aim, we first investigate a jet associated brightening in the OIR light curves of GX 339-4 during its 2011 outburst decay. The spectral energy distributions taken at the rising part of the OIR rebrightening yield flat spectra, indicating components other than optically thin emission from the compact jet. Again during the rising part of the brightening we detected fluctuations with the binary period of the system. Then, for a large sample of sources, we investigate the relation between the jet formation and the changes or differences in the short term X-ray variability, especially low frequency quasi periodic oscillations. We find that the X-ray variability patterns differ with respect to the source’s track in the radio X-ray correlation. We also discuss the nature of X-ray spectral softening within a few days prior to or following the start of the indications of the jet activity. Finally, we compare the relation between the spectral hardness and the reflection amplitude of black hole and neutron star systems to discuss the nature of their differences.