X-ray spectral and flux variability of the microquasar GRS 1758-258 on timescales from weeks to years

Understand

We present the spectral and timing evolution of the persistent black hole X-ray binary GRS 1758-258 based on almost 12 years of observations using the Rossi X-ray Timing Explorer Proportional Counter Array.

• While the source was predominantly found in the hard state during this time, it entered the thermally dominated soft state seven times.
• In the soft state GRS 1758-258 shows a strong decline in flux above 3 keV rather than the pivoting flux around 10 keV more commonly shown by black hole transients.
• In its 3-20 keV hardness intensity diagram, GRS 1758-258 shows a hysteresis of hard and soft state fluxes typical for transient sources in outburst.