Evidence for a Cool Disk and Inhomogeneous Coronae from Wide-band Temporal Spectroscopy of Cygnus X-1 with Suzaku

Abstract

Unified X-ray spectral and timing studies of Cygnus X-1 in the low/hard and hard intermediate state were conducted in a model-independent manner, using broadband Suzaku data acquired on 25 occasions from 2005 to 2009 with a total exposure of ~ 450 ks. The unabsorbed 0.1--500 keV source luminosity changed over 0.8--2.8% of the Eddington limit for 14.8 solar masses. Variations on short (1--2 seconds) and long (days to months) time scales require at least three separate components: a constant component localized below ~2 keV, a broad soft one dominating in the 2--10 keV range, and a hard one mostly seen in 10--300 keV range. In view of the truncated disk/hot inner flow picture, these are respectively interpreted as emission from the truncated cool disk, a soft Compton component, and a hard Compton component. Long-term spectral evolution can be produced by the constant disk increasing in temperature and luminosity as the truncation radius decreases. The soft Compton component likewise increases, but the hard Compton does not, so that the spectrum in the hard intermediate state is dominated by the soft Compton component; on the other hand, the hard Compton component dominates the spectrum in the dim low/hard state, probably associated with a variable soft emission providing seed photons for the Comptonization.

22 pages, 15 figures, PASJ accepted on April 2

References in corpus (65)

• X-ray Properties of Black-Hole Binaries
• Modelling the behaviour of accretion flows in X-ray binaries
• Advection-Dominated Accretion: Self-Similarity and Bipolar Outflows
• Hard X-ray Detector (HXD) on Board Suzaku
• RXTE Observation of Cygnus X-1: II. Timing Analysis
• Radiation mechanisms and geometry of Cygnus X-1 in the soft state
• Monte-Carlo Simulator and Ancillary Response Generator of Suzaku XRT/XIS System for Spatially Extended Source Analysis
• The evolution of black hole states
• Multi-Temperature Blackbody Spectrum of a Thin Accretion Disk around a Kerr Black Hole: Model Computations and Comparison with Observations
• Investigating a Fluctuating-accretion Model for the Spectral-timing Properties of Accreting Black Hole Systems
• The Two-Phase Pair Corona Model for Active Galactic Nuclei and X-ray Binaries: How to Obtain Exact Solutions
• On the X-ray time lags in the black hole candidates
• Plasma Ejection from Magnetic Flares and the X-ray Spectrum of Cygnus X-1
• The Mass of the Black Hole in Cygnus X-1
• In-Orbit Performance of the Hard X-ray Detector on board Suzaku
• Soft state of Cygnus X-1: stable disk and unstable corona
• Radiative Processes, Spectral States and Variability of Black-Hole Binaries
• Simultaneous X-ray and gamma-ray observations of Cyg X-1 in the hard state by Ginga and OSSE
• The Extreme Spin of the Black Hole in Cygnus X-1
• The Arcminute Microkelvin Imager
• The causal connection between disc and power-law variability in hard state black hole X-ray binaries
• The Trigonometric Parallax of Cygnus X-1
• Broad-band X-ray/gamma-ray spectra and binary parameters of GX 339-4 and their astrophysical implications
• Understanding the long-term spectral variability of Cygnus X-1 with BATSE and ASM observations
• Accretion disc variability in the hard state of black hole X-ray binaries
• The ASTRO-H Mission
• Orbital, precessional and flaring variability of Cygnus X-1
• Multiwavelength campaign on Mrk 509. IV. Optical-UV-X-ray variability and the nature of the soft X-ray excess
• X-ray irradiation in XTE J1817-330 and the inner radius of the truncated disc in the hard state
• On the determination of the spin of the black hole in Cyg X-1 from X-ray reflection spectra
• The hard X-ray spectral evolution in X-ray binaries and its application to constrain the black hole mass of ultraluminous X-ray sources
• Probing the Inner Region of Cyg X-1 in the Low/Hard State through its X-ray Broad Band Spectrum
• Corona, Jet, and Relativistic Line Models for Suzaku/RXTE/Chandra-HETG Observations of the Cygnus X-1 Hard State
• Suzaku Results on Cygnus X-1 in the Low/Hard State
• Broad band spectrum of Cygnus X-1 in two spectral states with BeppoSAX
• An optically thick inner corona geometry for the Very High State Galactic Black Hole XTE J1550-564
• Superorbital variability of X-ray and radio emission of Cyg X-1 - II. Dependence of the orbital modulation and spectral hardness on the superorbital phase
• Frequency resolved spectroscopy of Cyg X-1: fast variability of the reflected emission in the soft state
• Evidence for a compact jet dominating the broadband spectrum of the black hole accretor XTE J1550-564
• Thermal synchrotron radiation and its Comptonization in compact X-ray sources
• Broad-band spectra of Cyg X-1 and correlations between spectral characteristics
• Patterns of energy-dependent variability from Comptonization
• A transient relativistic radio jet from Cygnus X-1
• A synchrotron self-Compton -- disk reprocessing model for optical/X-ray correlation in black hole X-ray binaries
• Restoring the Suzaku Source Position Accuracy and Point-Spread Function
• Evidence for a change in the X-ray radiation mechanism in the hard state of Galactic black holes
• Multiwavelength spectral evolution during the 2011 outburst of the very faint X-ray transient Swift J1357.2-0933
• Using the X-ray Dust Scattering Halo of Cygnus X-1 to determine distance and dust distributions
• A self-consistent hybrid Comptonization model for broad-band spectra of accreting supermassive black holes
• Modeling the hard states of XTE J1550--564 during its 2000 outburst
• X-Ray and Near-Infrared Observations of GX 339-4 in the Low/Hard State with Suzaku and IRSF
• On the Role of the Accretion Disk in Black Hole Disk-Jet Connections
• A Global Study of the Behaviour of Black Hole X-ray Binary Discs
• The `harder when brighter' X-ray behaviour of the low luminosity active galactic nucleus NGC 7213
• Data-oriented Diagnostics of Pileup Effects on the Suzaku XIS
• Low/Hard State Spectra of GRO J1655-40 Observed with Suzaku
• Suzaku Studies of Wide-Band Spectral Variability of the Bright Type I Seyfert Galaxy Markarian 509
• An additional soft X-ray component in the dim low/hard state of black hole binaries
• The Nature of the Stable Soft X-ray Emissions in Several Types of Active Galactic Nuclei Observed by Suzaku
• Is the black hole in GX 339-4 really spinning rapidly?
• Testing Accretion Disk Structure with Suzaku data of LMC X-3
• Suzaku Discovery of a Hard Component Varying Independently of the Power-Law Emission in MCG-6-30-15
• Spectral and Timing Studies of Cyg X-1 in the Low/Hard State with Suzaku
• Radiative Spectra from Disk Corona and Inner Hot Flow in Black Hole X-ray Binaries
• Improvements in calibration of GSO scintillators in the Suzaku Hard X-ray Detector

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• MAXI observations of long-term variations of Cygnus X-1 in the low/hard and the high/soft states
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• The Accreting Black Hole Swift J1753.5-0127 from Radio to Hard X-Ray
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• Multi-wavelength spectroscopy of the black hole candidate MAXI J1813-095 during its discovery outburst
• Probing the shot behaviour in Cygnus X-1 using simultaneous AstroSat-NICER observation
• X-ray and Optical Observations of the Black Hole Candidate MAXI J1828-249
• Probing the hard and intermediate states of X-ray binaries using short time-scale variability
• Evolution of Accretion Disk Structure of the Black Hole X-ray Binary MAXI J1820$+$070 during the Rebrightening Phase
• On the Zeeman Effect in Magnetically-Arrested Disks
• Polarized X-rays Correlated with Short--Timescale Variability of Cygnus X-1
• Systematic Analysis of Low/Hard State RXTE Spectra of GX 339-4 to Constrain the Geometry of the System
• The New Primary X-ray Component Confirmed in the Seyfert I Galaxy IC4329A
• Recurrent Instability in LMXB Accretion Disks: How Strange is GRS 1915+105?
• Wind accretion onto compact objects
• Semi-Analytical Model for Wind-Fed Black Hole High-Mass X-ray Binaries -- State Transition Triggered by Magnetic Fields from the Companion Star --
• Evolution of X-ray and optical rapid variability during the low/hard state in the 2018 outburst of MAXI J1820+070 = ASASSN-18ey