A simple model for the complex lag structure of microquasars

Varnière, P.

doi:10.1051/0004-6361:200500096

Cited by 5 publications

(4 citation statements)

References 9 publications

(17 reference statements)

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“…The phase lag between the hard and soft X-ray photons in GRS 1915+105 changes sign during the plateau state and produce complex behavior (Muno et al 2001). Varniere (2005) has suggested that anything located inside the inner radius of the accretion disk (in our case wind) that can absorb a small part of soft X-ray flux can explain the changing of sign of the lag and its complex behavior during the plateau state. Other consequences of our results is that one would not expect oscillations/ baby jet type of IR & radio emission in Cyg X-3 (not observed so far (Dhawan, Mirabel, & Rodriguez 2000)) as has been observed in GRS 1915+105 (Mirabel et al 1998;Eikenberry et al 1998;Ishwara-Chandra, Yadav, & Pramesh Rao 2002).…”

Section: Resultsmentioning

confidence: 91%

Connection between the Accretion Disk and Superluminal Radio Jets and the Role of the Radio Plateau State in GRS 1915+105

Yadav¹

2006

ApJ

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We investigate the association between the accretion disk during radio plateau state and the following superluminal relativistic radio jets with peak intensity varies from 200 mJy to 1000 mJy observed over a period of five years and present the evidences of direct accretion disc-jet connection in microquasar GRS 1915+105 . We have analysed RXTE PCA/HEXTE X-ray data and have found that the accretion rate,ṁ accr , as inferred from the X-ray flux, is very high during the radio plateaux. We suggest that the accretion disk during the radio plateaux always associated with radiation-driven wind which is manifested in the form of enhanced absorption column density for X-ray and the depleted IR emission. We find that the wind density increases with the accretion disk luminosity during the radio plateaux. The wind density is similar to the density of the warm absorber proposed in extragalactic AGNs and Quasars. We suggest a simple model for the origin of superluminal relativistic jets. Finally, We discuss the implications of this work for galactic microquasars and the extragalactic AGNs and Quasars.

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Section: Resultsmentioning

confidence: 91%

Connection between the Accretion Disk and Superluminal Radio Jets and the Role of the Radio Plateau State in GRS 1915+105

Yadav¹

2006

ApJ

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“…The INTEGRAL data were retrieved from the public archive and correspond to the Target of Opportunity (TOO) observations performed between January 5, 2005 andFebruary 21, 2005 (MJD 53376.27-53422.05 …”

Section: Observations and Data Analysismentioning

confidence: 99%

“…While models based on Comptonisation of low-energy photons in a non-uniform corona can reproduce the amplitude and energy dependence of the hard lags the change in sign of the lags are hard to explain by invoking light-travel time differences between photons at different energies (but see Ohkawa et al 2005). Recently, Varnière (2005) has proposed that partial absorption (related to the jet mechanism) of the signal can account for the phase lag reversal in microquasars. Since X-ray pulsars do not show radio jets, other mechanisms producing the absorption of the soft/low-energy X-rays must be at work if the phase lag behaviour of V0332+53 is to be explained with this model.…”

Section: Phase Lagsmentioning

confidence: 99%

Correlated X-ray spectral and timing variability of the Be/X-ray binary V0332+53/BQ Camelopardalis during a type II outburst

Reig

Martínez-Núñez

Reglero

2006

A&A

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Context. After more than 15 years of quiescence the Be/X-ray binary V0332+53 underwent a giant outburst in December 2004. Aims. We have investigated the timing properties of the source in correlation with its spectral states as defined by different positions in the colour-colour diagram. Methods. We have used RXTE and INTEGRAL light curves to obtain colour-colour diagrams, power spectra and phase-lag spectra. The power spectra were fitted with a multi-Lorentzian function. Results. The source shows two distinct branches in the colour-colour diagram that resemble those of the Z sources. The hard branch (similar to the horizontal branch of Z sources) is characterised by a low-amplitude change of the hard colour compared to the change in the soft colour. In the soft branch (analogue to the normal branch) the amplitude of variability of the hard colour is about three times larger than that of the soft colour. As the count rate decreases the source moves up gradually through the soft to the hard branch. The aperiodic variability (excluding the pulse noise) consists of band-limited noise (represented by three broad Lorentzian components) and two QPOs at 0.05 Hz and 0.22 Hz. The strength of the lower frequency QPO increases as the source approaches the hard branch (similar to HBOs in Z sources). The higher frequency QPO reaches maximum significance when the source is in the middle of the branch (like NBOs). We have performed the first measurements of phase lags in the band limited noise below 8 Hz in an accreting X-ray pulsar and found that soft lags dominate at high frequencies. Above the pulse frequency (0.23 Hz), the amplitude of the lag increases as the X-ray flux increases. Conclusions.The Z topology appears to be a signature of the neutron star binaries as it is present in all types of neutron-star binaries (Z, atoll and, as we show here, in accreting pulsars as well). However, the motion along this track, the time scales through the different branches of the diagram and the aperiodic variability associated with portions of the Z track differ for each subclass of neutron-star binary.

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“…Psaltis et al,1999). Here we focus on a basic paradigm for the modulation and leave explanations of possible harmonic relations and phase lag behavior Varnière (2005) for further work. Black hole microquasars avoid the role of any solid stellar surface, and offer a purer probe of the accretion process without interaction with a stellar surface.…”

Section: Introductionmentioning

confidence: 99%

Flux modulation from non-axisymmetric structures in accretion discs

Blackman

2005

New Astronomy

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A simple model for the complex lag structure of microquasars

Cited by 5 publications

References 9 publications

Connection between the Accretion Disk and Superluminal Radio Jets and the Role of the Radio Plateau State in GRS 1915+105

Connection between the Accretion Disk and Superluminal Radio Jets and the Role of the Radio Plateau State in GRS 1915+105

Correlated X-ray spectral and timing variability of the Be/X-ray binary V0332+53/BQ Camelopardalis during a type II outburst

Flux modulation from non-axisymmetric structures in accretion discs

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