Correlated X-ray Spectral and Timing Behavior of the Black Hole Candidate

We present an analysis of data of the black hole candidate and X-ray transient XTE J1550-564, taken with the Rossi X-Ray Timing Explorer between 1998 November 22 and 1999 May 20. During this period the source went through several different states, which could be divided into soft and hard states based on the relative strength of the high-energy spectral component. These states showed up as distinct branches in the color-color and hardness-intensity diagrams, connecting to form a structure with a comblike topology, the branch corresponding to the soft state forming the spine and the branches corresponding to the various hard states forming the teeth of the comb. The power spectral properties of the source were strongly correlated with its position on the branches. The broadband noise became stronger and changed from power law-like to band-limited, as the spectrum became harder. Three types of quasi-periodic oscillations (QPOs) were found: 1-18 Hz and 102-284 Hz QPOs on the hard branches, and 16-18 Hz QPOs on and near the soft branch. The 1-18 Hz QPOs on the hard branches could be divided into three subtypes. The frequencies of the high- and low-frequency QPOs on the hard branches were correlated with each other and were anticorrelated with spectral hardness. The changes in QPO frequency suggest that the inner disk radius only increases by a factor of 3-4 as the source changes from a soft to a hard state. Our results on XTE J1550-564 strongly favor a two-dimensional description of black hole behavior, where the regions near the spine of the comb in the color-color diagram can be identified with the high state, and the teeth with transitions from the high state, via the intermediate state (which includes the very high state) to the low state, and back. The two physical parameters underlying this two-dimensional behavior vary to a large extent independently and could for example be the accretion rate through the disk and the size of the Comptonizing region causing the hard tail. The difference between the various teeth is then associated with the mass accretion rate through the disk, suggesting that high state ↔ low state transitions can occur at any disk mass accretion rate and that these transitions are primarily caused by another, independent parameter. We discuss how this picture could tie in with the canonical, one-dimensional behavior of black hole candidates that has usually been observed.

[1]  D. Psaltis,et al.  Correlations in Quasi-periodic Oscillation and Noise Frequencies among Neutron Star and Black Hole X-Ray Binaries , 1999, astro-ph/9902130.

[2]  R. Wijnands,et al.  Simultaneous Measurements of X-Ray Luminosity and Kilohertz Quasi-Periodic Oscillations in Low-Mass X-Ray Binaries , 2000, astro-ph/0002074.

[3]  Alan M. Levine,et al.  Complete RXTE Spectral Observations of the Black Hole X-ray Nova XTE J1550–564 , 2000 .

[4]  R. Wijnands,et al.  The Complex Phase-Lag Behavior of the 3-12 Hz Quasi-Periodic Oscillations during the Very High State of XTE J1550–564 , 1999, The Astrophysical journal.

[5]  Shunji Kitamoto,et al.  A jet model for a very high state of GX 339-4 , 1991 .

[6]  Martin C. Weisskopf,et al.  On searches for pulsed emission with application to four globular cluster X-ray sources - NGC 1851, 6441, 6624, and 6712 , 1983 .

[7]  W. Cui,et al.  EVIDENCE FOR FRAME-DRAGGING AROUND SPINNING BLACK HOLES IN X-RAY BINARIES , 1997, astro-ph/9710352.

[8]  R. Narayan,et al.  Advection-Dominated Accretion and the Spectral States of Black Hole X-Ray Binaries: Application to Nova Muscae 1991 , 1997 .

[9]  Penn State,et al.  RXTE Observations of 0.1-300 Hz Quasi-periodic Oscillationsin the Microquasar GRO J1655–40 , 1998, astro-ph/9806049.

[10]  K. Jahoda,et al.  Discovery of Submillisecond Quasi-periodic Oscillations in the X-Ray Flux of Scorpius X-1 , 1996, astro-ph/9607047.

[11]  W. Paciesas,et al.  The 1996 Soft State Transition of Cygnus X-1 , 1997, astro-ph/9701027.

[12]  Dan McCammon,et al.  Interstellar photoelectric absorption cross-sections, 0.03-10 keV , 1983 .

[13]  E. Ford,et al.  Strong Correlation between Noise Features at Low Frequency and the KilohertzQuasi-Periodic Oscillations in the X-Ray Binary 4U 1728–34 , 1998, astro-ph/9808148.

[14]  Hitoshi Negoro,et al.  Canonical Time Variations of X-Rays from Black Hole Candidates in the Low-Intensity State , 1992 .

[15]  J. Lense,et al.  Über den Einfluß der Eigenrotation der Zentralkörper auf die Bewegung der Planeten und Monde nach der Einsteinschen Gravitationstheorie , 1918 .

[16]  S. Kitamoto,et al.  Discovery and x-ray properties of GS 1124-683 (= Nova Muscae) , 1992 .

[17]  William W. Zhang,et al.  In-orbit performance and calibration of the Rossi X-ray Timing Explorer (RXTE) Proportional Counter Array (PCA) , 1996, Optics & Photonics.

[18]  D. E. Lehr,et al.  The 67 Hz Feature in the Black Hole Candidate GRS 1915+105 as a Possible “Diskoseismic” Mode , 1996, astro-ph/9612142.

[19]  J. Orosz,et al.  X-Ray Nova XTE J1550–564: Discovery of a Quasi-periodic Oscillation near 185 Hz , 1999 .

[20]  K. Koyama,et al.  Frontiers of X-ray astronomy , 1992 .

[21]  G. Hasinger,et al.  An Intermediate State of Cygnus X-1 , 1996 .

[22]  M. Trifoglio,et al.  Broadband Spectrum of Cygnus X-1 in Two Spectral States with BeppoSAX , 2000, astro-ph/0009160.

[23]  T. Oosterbroek,et al.  Quasi-periodic Oscillations in Black Hole Candidates as an Indicator of Transition between Low and High States , 1998, astro-ph/9807235.

[24]  W. Cui,et al.  Phase Lag and Coherence Function of X-Ray Emission from Black Hole Candidate XTE J1550–564 , 2000, The Astrophysical journal.

[25]  M. Klis,et al.  The EXOSAT Data on GX 339–4: Further Evidence for an “Intermediate” State , 1996, astro-ph/9611015.

[26]  S. Kitamoto,et al.  Normalized Power Spectral Densities of Two X-Ray Components from GS 1124-683 , 1994 .

[27]  J. Paradijs,et al.  The lives of the neutron stars , 1995 .

[28]  Psaltis,et al.  Quasi-Periodic Variability and the Inner Radii of Thin Accretion Disks in Galactic Black Hole Systems , 1999, The Astrophysical journal.

[29]  Jochen Greiner,et al.  RXTE Observations of QPOs in the Black Hole Candidate GRS 1915+105 , 1997 .

[30]  Wei Cui,et al.  Spectral Transitions in Cygnus X-1 and Other Black Hole X-Ray Binaries , 1997, astro-ph/9711167.

[31]  S. Corbel,et al.  Quenching of the Radio Jet during the X-Ray High State of GX 339–4 , 1999, astro-ph/9905121.

[32]  Kazuhisa Mitsuda,et al.  Spectral and Temporal Variability in the X-Ray Flux of GS 1124–683, Nova Muscae 1991 , 1997 .

[33]  R. Wade.  Analysis of cataclysmic variable star energy distributions , 1982 .

[34]  C. Markwardt,et al.  Observation of Kilohertz Quasi-periodic Oscillations from the Atoll Source 4U 1702–429 by the Rossi X-Ray Timing Explorer , 1999 .

[35]  M. van der Klis.  Millisecond Oscillations in X-ray Binaries , 2000 .

[36]  M. Nowak.  TOWARD A UNIFIED VIEW OF BLACK-HOLE HIGH-ENERGY STATES , 1995, astro-ph/9509046.

[37]  D. Psaltis,et al.  Discovery of Kilohertz Quasi-periodic Oscillations in GX 17+2 , 1997, astro-ph/9710013.

[38]  Rudy WijnandsMichiel van der Klis.  The broadband power spectra of x-ray binaries , 1998, astro-ph/9810342.

[39]  E.P.J. van den Heuvel,et al.  Black holes in binaries and galactic nuclei , 2001 .

[40]  J. Orosz,et al.  CORRELATIONS BETWEEN LOW-FREQUENCY QUASI-PERIODIC OSCILLATIONS AND SPECTRAL PARAMETERS IN XTE J1550(564 AND GRO J1655(40 , 1999, astro-ph/9910519.