Speaker
Description
X-ray binaries are among the brightest objects of our Galaxy in the high-energy domain (0.1-100 keV). Despite a relatively good knowledge of their basic emission mechanisms, we still lack a complete understanding of their time, energy, and luminosity dependence. We will present results obtained from a detailed study of a transient Be X-ray pulsar 4U 1901+03. This source was followed by NuSTAR and Swift during its 2019 outburst. We found a strong dependence on the energy as well as luminosity for the source which can be used to map the accretion geometry. We further exploited a cross-correlation technique to compare the pulse profiles in different energy ranges and found that the pulse profiles display "phase-lags" at energies close to those of the cyclotron absorption feature at 30 keV. This feature at 30 keV is highly luminosity and pulse-phase dependent. We also discuss results from pulse phase-resolved spectroscopy to draw a coherent picture of the X-ray properties of the source using correlated timing and spectral studies.
