<i>Swift</i>Observations of the Cooling Accretion Disk of XTE J1817−330

Rykoff, E. S.; Miller, J. M.; Steeghs, D.; Torres, M. A. P.

doi:10.1086/520329

Cited by 139 publications

(200 citation statements)

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“…Although we have then observed the disc slowly moving outwards during the hardening (Chen et al 1997;Cadolle Bel et al 2004), this is not necessarily true for all transient sources (see, e.g., Miller et al 2006). This is still strongly debated (Done et al 2007;Rykoff et al 2007;Gierliński et al 2008) as, for example, in XTE J1817−330. We do not address this question specifically in this work because the majority of our data were taken in the LHS and not long after the main transition into softer states.…”

Section: Interpretationsmentioning

confidence: 70%

Overview of an extensive multi-wavelength study of GX 339−4 during the 2010 outburst

Bel

Rodríguez

D’Avanzo

et al. 2011

A&A

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Context. The microquasar GX 339−4 experienced a new outburst in 2010: it was observed simultaneously at various wavelengths from radio up to soft γ-rays. We focus on observations that are quasi-simultaneous with those made with the INTEGRAL and RXTE satellites: these were collected in 2010 March-April during our INTEGRAL target of opportunity programme, and during some of the other INTEGRAL observing programmes with GX 339−4 in the field-of-view. Aims. X-ray transients are extreme systems that often harbour a black hole, and are known to emit throughout the whole electromagnetic spectrum when in outburst. The goals of our programme are to understand the evolution of the physical processes close to the black hole and to study the connections between the accretion and ejection. Methods. We analysed radio, NIR, optical, UV, X-ray and soft γ-ray observations. We studied the source evolution in detail by producing light curves, hardness-intensity diagrams and spectra. We fitted the broadband data with phenomenological, then physical, models to study the emission coming from the distinct components. Results. Based on the energy spectra, the source evolved from the canonical hard state to the canonical soft state. The source showed X-ray spectral variations that were correlated with changes in radio, NIR and optical emission. The bolometric flux increased from 0.8 to 2.9 × 10 −8 erg cm −2 s −1 while the relative flux and contribution of the hot medium decreased on the average. Reprocessing in the disc was likely to be strong at the end of our observations. Conclusions. The source showed a behaviour similar to that of previous outbursts, with some small deviations in the hard X-ray parameter evolution. The radio, NIR and optical emission from jets was detected and observed to fade as the source softened. The results are discussed within the context of disc and jet models.

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Section: Interpretationsmentioning

confidence: 70%

Overview of an extensive multi-wavelength study of GX 339−4 during the 2010 outburst

Bel

Rodríguez

D’Avanzo

et al. 2011

A&A

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“…A similar spectral decomposition is also possible for black hole sources in their low/hard states, where a very soft component, together with a reflection component arising in an untruncated accretion disk, is claimed to be present by some authors (Miller et al 2006b,a;Rykoff et al 2007), but it is rejected by others (Done & Gierliński 2006;D'Angelo et al 2008;Gierliński et al 2008;Hiemstra et al 2009;Cabanac et al 2009). However, in black holes, there is no balance required in the energetics of the components that make up the overall X-ray emission, as the quantity of energy advected beyond the event horizon is an unknown variable.…”

Section: Modelmentioning

confidence: 73%

A self-consistent approach to the hard and soft states of 4U 1705-44

D’Aí¹,

Salvo²,

Ballantyne

et al. 2010

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Context. High-resolution spectroscopy has recently revealed in many low-mass X-ray binaries hosting a neutron star that the shape of the broad iron line observed in the 6.4-6.97 keV range is consistently well-fitted by a relativistically smeared line profile. Aims. The presence of other broad features, besides the iron line, together with a high S/N of the spectra offer the possibility of testing a self-consistent approach to the overall broadband reflection spectrum and evaluating the impact of the reflection component in the formation of the broadband X-ray spectra. Methods. We analyzed two XMM-Newton observations of the bright atoll source 4U 1705-44, which can be considered a prototype of the class of the persistent NS LMXBs showing both hard and soft states. The first observation was performed when the source was in a hard low flux state, the second during a soft, high-flux state. Both the spectra show broad iron emission lines. We fit the spectra using a two-component model, together with a reflection model specifically suited to the case of a neutron star, where the incident spectrum has a blackbody shape. Results. In the soft state, the reflection model, convolved with a relativistic smearing component, consistently describes the broad features present in the spectrum, and we find a clear relation between the temperature of the incident flux and the temperature of the harder X-ray component that we interpret as the boundary layer emission. In this state we find converging evidence that the boundary layer outer radius is ∼2 times the neutron star radius. In the low flux state, we observe a change in the continuum shape of the spectrum with respect to the soft state. Still, the broad local emission features can be associated with a disk reflecting matter, but in a lower ionization state, and possibly produced in an accretion disk truncated at greater distance. Conclusions. Our analysis provides strong evidence that the reflection component in soft states of LMXBs comes from to hard X-ray thermal irradiation, which we identify with the boundary layer emission, also present in the continuum model. In the hard state, the broad iron line if also produced by reflection, and the continuum disk emission can be self-consistently accounted if the disk is truncated at a greater distance than the soft state.

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“…Assuming that this outburst is similar to that in GRO J1655-40 (CDNP08) we expect that once the object goes to the low-hard state, it will take about 32-38 days to return to quiescence and the QPO frequency would monotonically decrease from ∼6 Hz to a few mHz in that period. Miller et al (2006), Ramadevi & Seetha (2007), and Rykoff et al (2007) recently argued that the presence of a thermal emission even in the low-hard state of some outburst sources points to a Keplerian disk with an inner edge very close to the black hole. The objects exhibit a behavior similar to a classical outburst with FRED-type lightcurve.…”

Section: Discussion and Concluding Remarksmentioning

confidence: 99%

Properties of the propagating shock wave in the accretion flow around GX 339-4 in the 2010 outburst

Debnath

Chakrabarti

Nandi

2010

A&A

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Context. The black hole candidate GX 339-4 exhibited an X-ray outburst in January 2010, which is still continuing. We here discuss the timing and the spectral properties of the outburst using RXTE data. Aims. Our goal is to study the timing and spectral properties of GX 339-4 using its recent outburst data and extract information about the nature of the accretion flow. Methods. We use RXTE archival data of the recent GX 339-4 outburst and analyze them with the NASA HEAsoft package, version 6.8. We then compare the observed quasi-periodic oscillation (QPO) frequencies with those from existing shock oscillation model and obtain the nature of evolution of the shock locations during the outburst. Results. We found that the QPO frequencies are monotonically increasing from 0.102 Hz to 5.69 Hz within a period of ∼26 days. We explain this evolution with the propagating oscillatory shock (POS) solution and find the variation of the initial and final shock locations and strengths. The model fits also give the velocity of the propagating shock wave, which is responsible for the generation of QPOs and their evolutions, at ∼10 m s −1 . We observe from the spectra that up to 2010 April 10, the object was in a hard state. After that, it went to the hard-intermediate state. On April 18, it had a state transition and went to the soft-intermediate state. On May 15, another state transition was observed and the source moved to the soft state. Conclusions. As in the previously fitted outburst sources, this source also showed the tendency of a rapidly increasing QPO frequency (ν QPO ) on a viscous time scale, which can be modeled quite accurately. In this case, the shock seems to have disappeared at about ∼172 Schwarzschild radii, unlike in the 2005 outburst of GRO J1655-40, where the shock disappeared behind the horizon.

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SwiftObservations of the Cooling Accretion Disk of XTE J1817−330

Cited by 139 publications

References 35 publications

Overview of an extensive multi-wavelength study of GX 339−4 during the 2010 outburst

Overview of an extensive multi-wavelength study of GX 339−4 during the 2010 outburst

A self-consistent approach to the hard and soft states of 4U 1705-44

Properties of the propagating shock wave in the accretion flow around GX 339-4 in the 2010 outburst

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