An IR, optical and X-ray study of the two state behaviour of GX 339-4

Motch, C.; Ilovaisky, S. A.; Chevalier, C.; Angebault, P.

doi:10.1007/bf00212888

Cited by 41 publications

(55 citation statements)

References 4 publications

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“…We see no evidence of characteristic timescales (such as power-law breaks or QPOs). Other studies that have observed QPOs during the hard (Motch et al 1985;Gandhi 2009;Gandhi et al 2010) and soft (Motch et al 1985) state have been for timescales much less than what we have observed here ( 250 s). In future work we will obtain data with higher temporal resolution in an attempt to bridge the timescale-gap between 250 s and 4 days during both hard and soft X-ray states, and construct PSDs, cross-, and autocorrelation functions to fully explore variability timescales in GX 339-4 to see any evidence of characteristic timescale(s) related to accretion processes.…”

Section: Discussioncontrasting

confidence: 69%

“…During this phase GX 339-4 rapidly fades, more in the IR than the optical. We note that Motch et al (1985) was the first to see a change in optical brightness over the transition from hard to soft states. This sudden drop in O/IR flux during 2002 was also noted by .…”

Section: Hard-to-soft Transitionmentioning

confidence: 67%

“…Very little has been done during the soft state in GX 339-4. Motch et al (1985) found no sign of variability in the power-density spectrum (PSD) of soft-state optical data. Quasi-periodic oscillations (QPOs) ranging between 0.05 and 1 Hz have been observed in the PSD of hard-state data (Motch et al 1985;Gandhi 2009;Gandhi et al 2010) that may be attributed to oscillations within the accretion disk.…”

Section: Introductionmentioning

confidence: 95%

“…Motch et al (1985) found no sign of variability in the power-density spectrum (PSD) of soft-state optical data. Quasi-periodic oscillations (QPOs) ranging between 0.05 and 1 Hz have been observed in the PSD of hard-state data (Motch et al 1985;Gandhi 2009;Gandhi et al 2010) that may be attributed to oscillations within the accretion disk. Cross-correlation and autocorrelation functions obtained from hard-state data show that optical emission lags X-ray emission by ∼150 ms (Gandhi et al 2008) while the IR lags X-rays by ∼100 ms (Casella et al 2010).…”

Section: Introductionmentioning

confidence: 95%

“…The location of the non-thermal power-law break is an important parameter as it is used to estimate the jet power (Fender 2006). Motch et al (1985) first showed that, during the hard state, the IR to X-ray SED was well explained by a single power-law fit with a slope of α = −0.58. Subsequently, constructed two SEDs with quasi-simultaneous radio, O/IR, and X-ray data and suggested that the power law breaks in the near-IR.…”

Section: Introductionmentioning

confidence: 99%

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Optical and Near-Infrared Monitoring of the Black Hole X-Ray Binary Gx 339-4 During 2002-2010

Buxton¹,

Bailyn²,

Capelo³

et al. 2012

The Astronomical Journal

102

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We present the optical/infrared (O/IR) light curve of the black hole X-ray binary GX 339-4 collected at the SMARTS 1.3 m telescope from 2002 to 2010. During this time the source has undergone numerous state transitions including hard-to-soft state transitions when we see large changes in the near-IR flux accompanied by modest changes in optical flux, and three rebrightening events in 2003, 2005, and 2007 after GX 339-4 transitioned from the soft state to the hard. All but one outburst show similar behavior in the X-ray hardness-intensity diagram. We show that the O/IR colors follow two distinct tracks that reflect either the hard or soft X-ray state of the source. Thus, either of these two X-ray states can be inferred from O/IR observations alone. From these correlations we have constructed spectral energy distributions of the soft and hard states. During the hard state, the near-IR data have the same spectral slope as simultaneous radio data when GX 339-4 was in a bright optical state, implying that the near-IR is dominated by a non-thermal source, most likely originating from jets. Non-thermal emission dominates the near-IR bands during the hard state at all but the faintest optical states, and the fraction of non-thermal emission increases with increasing optical brightness. The spectral slope of the optical bands indicate that a heated thermal source is present during both the soft and hard X-ray states, even when GX 339-4 is at its faintest optical state. We have conducted a timing analysis of the light curve for the hard and soft states and find no evidence of a characteristic timescale within the range of 4-230 days.

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Section: Discussioncontrasting

confidence: 69%

Section: Hard-to-soft Transitionmentioning

confidence: 67%

Section: Introductionmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

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Optical and Near-Infrared Monitoring of the Black Hole X-Ray Binary Gx 339-4 During 2002-2010

Buxton¹,

Bailyn²,

Capelo³

et al. 2012

The Astronomical Journal

102

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X-ray and radio monitoring of GX 339-4 and CYG X-1

Nowak

Astrophysics and Space Science

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Previous work by Motch et al. (1985) suggested that in the low/hard state of GX 339−4, the soft X-ray power-law extrapolated backward in energy agrees with the IR flux level. Corbel and Fender (2002) later showed that the typical hard state radio power-law extrapolated forward in energy meets the backward extrapolated X-ray power-law at an IR spectral break, which was explicitly observed twice in GX 339−4. This has been cited as further evidence that jet synchrotron radiation might make a significant contribution to the observed X-rays in the hard state. We explore this hypothesis with a series of simultaneous radio/X-ray hard state observations of GX 339−4. We fit these spectra with a simple, but remarkably successful, doubly broken power-law model that indeed requires a spectral break in the IR. For most of these observations, the break position as a function of X-ray flux agrees with the jet model predictions. We then examine the radio flux/X-ray flux correlation in Cyg X-1 through the use of 15 GHz radio data, obtained with the Ryle radio telescope, and Rossi X-ray Timing Explorer data, from the All Sky Monitor and pointed observations. We find evidence of 'parallel tracks' in the radio/X-ray correlation which are associated with 'failed transitions' to, or the beginning of a transition to, the soft state. We also find that for Cyg X-1 the radio flux is more fundamentally correlated with the hard, rather than the soft, X-ray flux. r[2]. This correlation was seen to hold over several decades in X-ray flux, and also to hold for two hard state epochs that were separated by a prolonged, intervening soft state outburst.

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5.6.5 Black holes

Trümper¹,

Fink²

Stars and Star Clusters

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An IR, optical and X-ray study of the two state behaviour of GX 339-4

Cited by 41 publications

References 4 publications

Optical and Near-Infrared Monitoring of the Black Hole X-Ray Binary Gx 339-4 During 2002-2010

Optical and Near-Infrared Monitoring of the Black Hole X-Ray Binary Gx 339-4 During 2002-2010

X-ray and radio monitoring of GX 339-4 and CYG X-1

5.6.5 Black holes

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