BeppoSAX Observations of the Power and Energy Spectral Evolution in the Black Hole Candidate XTE J1650-500

Abstract

We study the time variability and spectral evolution of the Black Hole Candidate source XTE J1650-500 using the BeppoSax wide energy range (0.12-200 keV) observations performed during the 2001 X-ray outburst. The source evolves from a low/hard state (LHS) toward a high/soft state (HSS). In all states the emergent photon spectrum is described by the sum of Comptonization and soft (disk) blackbody components. In the LHS, the Comptonization component dominates in the resulting spectrum. On the other hand, during the HSS the soft (disk) component is already dominant. In this state the Comptonization part of the spectrum is much softer than that in the LHS (photon index is ~ 2.4 in the HSS vs. that is ~1.7 in the LHS). In the BeppoSAX data we find a strong signature of the index saturation with the mass accretion rate which can be considered as an observational evidence of the converging flow (black hole) in XTE J1650-500. We derive power spectra (PS) of the source time variability in different spectral states as a function of energy band. When the source undergoes a transition to softer states, the PS as a whole is shifted to higher frequencies which can be interpreted as a contraction of the Compton cloud during hard-soft spectral evolution. It is worthwhile to emphasize a detection of a strong low-frequency red noise component in the HSS PS which can be considered a signature of the presence of the strong extended disk in the HSS. Also as a result of our data analysis, we find a very weak sign of K_alpha line appearance in these BeppoSAX data. This finding does not confirm previous claims by Miniutti et al. on the presence of a broad and strongly relativistic iron emission line in this particular set of the BeppoSAX data.

31 pages, 10 figures, accepted for publication in the ApJ

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• The X-ray Power Spectral Density Function of the Seyfert Active Galactic Nucleus NGC 7469
• NGC 4051: Black hole mass and photon index-mass accretion rate correlation
• Disentangling the NIR/optical emission of the black hole XTE J1650-500 during outburst
• Time-domain variability properties of XTE J1650-500 during its 2001 outburst: Evidence of disc-jet connection
• Hard X-ray/Soft gamma-ray experiments and missions: overview and prospects
• Spectral evolution of the X-ray nova XTE J1859+226 during its outburst observed by BeppoSAX and RXTE
• Suzaku Observations of the Galactic Center Microquasar 1E 1740.7-2942
• Insight-HXMT Detections of Hard X-ray Tails in Scorpius X-1
• X-ray linear polarization prediction in Black-Hole binaries and Active Galactic Nuclei and its measurements by IXPE
• Smearing of mass accretion rate variation by viscous processes in accretion disks in compact binary systems