Quasi-periodic oscillations under wavelet microscope: the application of Matching Pursuit algorithm

Lachowicz, Pawel; Done, Chris

doi:10.1051/0004-6361/200913144

Cited by 21 publications

(21 citation statements)

References 60 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The type C QPO width sets the typical time‐scale for the QPO signal to remain coherent. Since the QPO is not always present in the light curve, there also exists an excitation time‐scale responsible for the QPO appearance (Lachowicz & Done 2010). The QPO can be broadened if the excitation time‐scale becomes shorter than the QPO time‐scale, as the excitation presumably interrupts the coherent QPO light curve by phase randomizing it.…”

Section: Discussionmentioning

confidence: 99%

“…Wagoner, Silbergleit & Ortega-Rodríguez (2001), Titarchuk & Osherovich (1999) and Tagger & Pellat (1999). there also exists an excitation time-scale responsible for the QPO appearance (Lachowicz & Done 2010). The QPO can be broadened if the excitation time-scale becomes shorter than the QPO timescale, as the excitation presumably interrupts the coherent QPO light curve by phase randomizing it.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Low-frequency oscillations in black holes: a spectral-timing approach to the case of GX 339-4

Motta¹,

Muñoz-Darias²,

Casella³

et al. 2011

Monthly Notices of the Royal Astronomical Society

203

266

View full text Add to dashboard Cite

We analysed Rossi X‐ray Timing Explorer (RXTE)/PCA and HEXTE data of the transient black hole binary GX 339‐4, collected over a time‐span of 8 years. We studied the properties and the behaviour of low‐frequency quasi‐periodic oscillations (QPOs) as a function of the integrated broad‐band variability and the spectral parameters during four outbursts (2002, 2004, 2007 and 2010). Most of the QPOs could be classified following the ABC classification which has been proposed before. Our results show that the ABC classification can be extended to include spectral dependencies and that the three QPO types have indeed intrinsically different properties. In terms of the relation between QPO frequency and power‐law flux, types A and C QPOs may follow the same relation, whereas the type B QPOs trace out a very different relation. Type B QPO frequencies clearly correlate with the power‐law flux and are connected to local increases of the count rate. The frequencies of all QPOs observed in the rising phase of the 2002, 2007 and 2010 outbursts correlate with the disc flux. Our results can be interpreted within the framework of the recently proposed QPO models involving Lense–Thirring precession. We suggest that types C and A QPOs might be connected and could be interpreted as being the result of the same phenomenon observed at different stages of the outburst evolution, while a different physical process produces type B QPOs.

show abstract

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Low-frequency oscillations in black holes: a spectral-timing approach to the case of GX 339-4

Motta¹,

Muñoz-Darias²,

Casella³

et al. 2011

Monthly Notices of the Royal Astronomical Society

203

266

View full text Add to dashboard Cite

show abstract

“…Clumps forming from random density fluctuations in regions high above the midplane could temporarily misalign the flow leading to intermittent precession. This predicted intermittency has the advantage of naturally explaining the observed random jumps in QPO phase (Miller & Homan ; Lachowicz & Done ).…”

Section: Model Geometrymentioning

confidence: 93%

The effect of frame dragging on the iron Kα line in X-ray binaries

Ingram¹,

Done²

2012

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

The clear characteristic time‐scale picked out by the low‐frequency quasi‐periodic oscillations (QPOs) seen in many black hole and neutron star binaries has the potential to provide a very powerful diagnostic of the inner regions of the accretion flow. However, this potential cannot be realized without a quantitative model for the QPO. We have recently shown that the same truncated disc/hot inner flow geometry which is used to interpret the spectral transitions can also directly produce the QPO from Lense–Thirring (vertical) precession of the hot inner flow. This correctly predicts both the frequency and spectrum of the QPO, and the tight correlation of these properties with the total spectrum of the source via a changing truncation radius between the disc and hot flow. This model predicts a unique iron line signature as a vertically tilted flow illuminates different azimuths of the disc as it precesses. The iron line arising from this rotating illumination is blueshifted when the flow irradiates the approaching region of the spinning disc and redshifted when the flow irradiates the receding region of the disc. This gives rise to a characteristic rocking of the iron line on the QPO frequency which is a necessary (and probably sufficient) test of a Lense–Thirring origin. This is also an independent test of disc truncation models for the low/hard state, as vertical precession cannot occur if there is a disc in the midplane. We show that it may be possible to observe this effect using archival data from the Rossi X‐ray Timing Explorer or XMM–Newton. However, a clean test requires a combination of moderate resolution and good statistics, such as would be available from a long XMM–Newton observation or with data from the proposed European Space Agency mission Large Observatory for X‐ray Timing.

show abstract

“…The model matches the trend in the data fairly well, and forms a lower limit to the width of the QPO. However, other effects such as the on‐time of the QPO (see Lachowicz & Done 2010) can decrease the coherence of the signal, so here we simply use the data to determine the QPO width (parametrized as the quality factor Q = f QPO /σ QPO ) after using the broad‐band noise surface density to determine the QPO frequency, f QPO .…”

Section: The Qpo: Precession and Surface Densitymentioning

confidence: 99%

A physical model for the continuum variability and quasi-periodic oscillation in accreting black holes

Ingram

Done

2011

Monthly Notices of the Royal Astronomical Society

226

209

View full text Add to dashboard Cite

The power spectra of black hole binaries have been well studied for decades, giving a very detailed phenomenological picture of the variability properties and their correlation with the energy spectrum (spectral state) of the source. Here we take the truncated disc/hot inner flow picture which can describe the spectral changes, and show that propagating mass accretion rate fluctuations in the hot flow can match the broad‐band power spectral properties seen in black hole binaries, i.e. give an approximately band‐limited noise between a low‐ and a high‐frequency break. The low‐frequency break marks the viscous time‐scale at the outer edge of the hot inner flow, which is the inner edge of the truncated disc. The fluctuations in mass accretion rate propagate towards the central object in a finite time meaning the high‐frequency break is more complex than simply the viscous time‐scale at the inner edge of the hot flow because fluctuations on time‐scales shorter than the propagation time are incoherent. The model also predicts the Lense–Thirring precession time‐scale of the hot flow, as this is set by the combination of inner and outer radius of the flow, together with its surface density which is self‐consistently calculated from the propagating fluctuations. We show that this naturally gives the observed relation between the low‐frequency break and quasi‐periodic oscillation (QPO) frequency as the outer radius of the flow moves inwards, and that this model predicts many of the observed QPO properties such as correlation of coherence with frequency, and of the recently discovered correlation of frequency with flux on short time‐scales. We fit this total model of the variability to a sequence of five observed power spectra from the bright black hole binary XTE J1550−564 as the source transitioned from a low/hard to very high state. This is the first time that a power spectrum from a black hole binary has been fit with a physical model for the variability. The data are well fit if the inner radius of the flow remains constant, while the outer radius sweeps inwards from ∼75 to 12 gravitational radii. This range of radii is the same range as required by models of the energy spectral evolution, giving the first self‐consistent description of the evolution of both the spectrum and variability of black hole binaries.

show abstract

Quasi-periodic oscillations under wavelet microscope: the application of Matching Pursuit algorithm

Cited by 21 publications

References 60 publications

Low-frequency oscillations in black holes: a spectral-timing approach to the case of GX 339-4

Low-frequency oscillations in black holes: a spectral-timing approach to the case of GX 339-4

The effect of frame dragging on the iron Kα line in X-ray binaries

A physical model for the continuum variability and quasi-periodic oscillation in accreting black holes

Contact Info

Product

Resources

About