Spectral Transitions in Cygnus X‐1 and Other Black Hole X‐Ray Binaries

Esin, A. A.; Narayan, Ramesh; Cui, Wei; Grove, J. E.; Zhang, Shuang‐Nan

doi:10.1086/306186

Cited by 258 publications

(337 citation statements)

References 94 publications

(153 reference statements)

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“…However, this was during the transition and VLA monitoring towards the end of the high/soft state period showed that, as found during previous state changes, the radio flux had dropped to ∼5 mJy (Zhang et al 1997b). Some authors (Belloni et al 1996, Esin et al 1998 have concluded that Cyg X-1 did not fully reach the soft/high state on this occasion in which case we may expect the radio source to not have disappeared as before. However, it should be noted that the radio source of GX339-4 diminishes during its X-ray intermediate/high state (Fender et al 1999 in prep) and, given the many similarities between these two systems in terms of their X-ray and radio properties, we may expect Cyg X-1 to behave likewise.…”

Section: Resultssupporting

confidence: 49%

“…When Cyg X-1 enters the less common soft X-ray state the accretion disc extends much further towards the black hole and the ADAF is restricted to the corona (Esin et al 1998). Increased activity in the disc causes additional heating and ionization of the stellar wind, resulting in a loss of the Hα emission line.…”

Section: Discussionmentioning

confidence: 99%

“…X-ray transitions from the soft to the low/hard state (see e.g. Esin et al 1998 and references therein for definitions of the various states of X-ray binaries) occurred simultaneously with an increase in radio flux from ∼5 mJy to ∼20 mJy, levelling out at ∼15 mJy (Tananbaum et al 1972a, Braes & Miley 1976. This has been observed more recently by the VLA -the radio flux increased from ∼5 mJy to ∼20 mJy simultaneously with the transition from the high/soft state back to the hard in August 1996 (Zhang et al 1997b).…”

Section: Introductionmentioning

confidence: 99%

“…The state transitions have been explained in terms of changes in the inner disc radius and the advection models of Esin et al (1998). During the usual hard X-ray state the inner disc radius is relatively large and hard X-ray emission is thought to be produced by the upscattering of disc photons by a Comptonised corona (Zhang et al 1997a).…”

Section: Introductionmentioning

confidence: 99%

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Orbital, Precessional and Flaring Variability in Cygnus X-1

Brocksopp¹,

Fender²,

Larianov³

et al.

Black Holes in Binaries and Galactic Nuclei: Diagnostics, Demography and Formation

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We present the results of a 2.5-year multiwavelength monitoring programme of Cygnus X-1, making use of hard and soft X-ray data, optical spectroscopy, UBVJHK photometry and radio data. In particular we confirm that the 5.6-day orbital period is apparent in all wavebands and note the existence of a wavelength-dependence to the modulation, in the sense that higher energies reach minimum first. We also find a strong modulation at a period of 142 ± 7 days, which we suggest is due to precession and/or radiative warping of the accretion disc. Strong modulation of the hard and soft X-ray flux at this long period may not be compatible with simple models of an optically thin accretion flow and corona in the low state. We present the basic components required for more detailed future modelling of the system -including a partially optically thick jet, quasi-continuous in the low state, the base of which acts as the Comptonising corona. In addition, we find that there are a number of flares which appear to be correlated in at least two wavebands and generally in more. We choose two of these flares to study in further detail and find that the hard and soft X-rays are well-correlated in the first and that the soft X-rays and radio are correlated in the second. In general, the optical and infrared show similar behaviour to each other but are not correlated with the X-rays or radio.

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Section: Resultssupporting

confidence: 49%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Orbital, Precessional and Flaring Variability in Cygnus X-1

Brocksopp¹,

Fender²,

Larianov³

et al.

Black Holes in Binaries and Galactic Nuclei: Diagnostics, Demography and Formation

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“…A more realistic model was introduced by Esin et al (1997;see also Narayan et al 1996;Narayan et al 1997;Esin et al 1998Esin et al , 2001, where the generic corona was replaced by a more physical Advection Dominated Accretion flow (ADAF; Narayan & Yi 1994, 1995Abramowicz et al 1995). In our interpretation of the q-shaped curve, we will start from the Esin et al (1997) model and will expand it to take into account the wealth of new information that has become available since then.…”

Section: Introductionmentioning

confidence: 99%

Accretion and Ejection in Black-Hole X-Ray Transients

Kylafis

Belloni

2014

The Formation and Disruption of Black Hole Jets

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Context. A rich phenomenology has been accumulated over the years regarding accretion and ejection in black-hole X-ray transients (BHTs) and it needs an interpretation. Aims. Here we summarize the current observational picture of the outbursts of BHTs, based on the evolution traced in a hardness -luminosity diagram (HLD), and we offer a physical interpretation. Methods. The basic ingredient in our interpretation is the Poynting -Robertson Cosmic Battery (PRCB, Contopoulos & Kazanas 1998), which provides locally the poloidal magnetic field needed for the ejection of the jet. In addition, we make two assumptions, easily justifiable. The first is that the mass-accretion rate to the black hole in a BHT outburst has a generic bell-shaped form, whose characteristic time scale is much longer than the dynamical or the cooling ones. This is guaranteed by the observational fact that all BHTs start their outburst and end it at the quiescent state, i.e., at very low accretion rate, and that state transitions take place over long time scales (hours to days). The second assumption is that at low accretion rates the accretion flow is geometrically thick, ADAF-like, while at high accretion rates it is geometrically thin. Last, but not least, we demonstrate that the previous history of the system is absolutely necessary for the interpretation of the HLD. Results. Both, at the beginning and the end of an outburst, the PRCB establishes a strong poloidal magnetic field in the ADAF-like part of the accretion flow, and this explains naturally why a jet is always present in the right part of the HLD. In the left part of the HLD, the accretion flow is in the form of a thin disk, and such a disk cannot sustain a strong poloidal magnetic filed. Thus, no jet is expected in this part of the HLD. Finally, the counterclockwise traversal of the HLD is explained as follows: all outbursts start from the quiescent state, in which the inner part of the accretion flow is ADAF-like, threaded by a poloidal magnetic field. As the accretion rate increases and the source moves to the hard state, the poloidal magnetic field in the ADAF forces the flow to remain ADAF and the source to move upwards in the HLD rather than to turn left. Thus, the history of the system determines the counterclockwise traversal of the HLD. As a result, no BHT is expected to ever traverse the entire HLD curve in the clockwise direction. Conclusions. We offer a physical interpretation of accretion and ejection in BHTs with only one parameter, the mass transfer rate, plus the history of the system.

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Accretion Disks

Spruit¹

NATO Science Series II. Mathematics, Physics and Chemistry

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Spectral Transitions in Cygnus X‐1 and Other Black Hole X‐Ray Binaries

Cited by 258 publications

References 94 publications

Orbital, Precessional and Flaring Variability in Cygnus X-1

Orbital, Precessional and Flaring Variability in Cygnus X-1

Accretion and Ejection in Black-Hole X-Ray Transients

Accretion Disks

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