The complex behaviour of the microquasar GRS 1915+105 in the<i>ρ</i>class observed with<i>Beppo</i>SAX

Mineo, T.; Massaro, E.; D’Aí, A.; Massa, F.; Feroci, M.; Ventura, G.; Casella, P.; Ferrigno, C.; Belloni, T.

doi:10.1051/0004-6361/201117369

Cited by 25 publications

(32 citation statements)

References 51 publications

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“…The idea that the QPO originates from the corona is also consistent with the fact that the QPO absolute amplitude is low at the pulse phase (Fig. 1) where the corona flux is at its minimum (Mineo et al 2012(Mineo et al , 2017, and with the result that both the QPO absolute amplitude and the corona flux at phase below ∼ 0.85 are coincidentally higher in the ρ2 class than in the ρ1 class ( Fig. 1; Fig.…”

Section: Qpo's Originsupporting

confidence: 78%

Disc–corona interaction in the heartbeat state of GRS 1915+105

Yan

Liu

et al. 2017

Monthly Notices of the Royal Astronomical Society

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Timing analysis provides information about the dynamics of matter accreting on to neutron stars and black holes, and hence is crucial for studying the physics of the accretion flow around these objects. It is difficult, however, to associate the different variability components with each of the spectral components of the accretion flow. We apply several new methods to two Rossi X-ray Timing Explorer observations of the black hole binary GRS 1915+105 during its heartbeat state to explore the origin of the X-ray variability and the interactions of the accretion-flow components. We offer a promising window into the disc-corona interaction through analysing the formation regions of the disc aperiodic variabilities with different time-scales via comparing the corresponding transition energies of the amplitude-ratio spectra. In a previous paper, we analysed the Fourier power density as a function of energy and frequency to study the origin of the aperiodic variability, and combined that analysis with the phase lag as a function of frequency to derive a picture of the disc-corona interaction in this source. We here, for the first time, investigate the phase lag as a function of energy and frequency, and display some interesting details of the disc-corona interaction. Besides, the results from the shape of amplitude-ratio spectrum and from several other aspects suggest that the quasi-periodic oscillation originates from the corona.

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Section: Qpo's Originsupporting

confidence: 78%

Disc–corona interaction in the heartbeat state of GRS 1915+105

Yan

Liu

et al. 2017

Monthly Notices of the Royal Astronomical Society

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“…The energy spectra at the peak flux level and persistent flux level have been modelled with the disc blackbody (with and without zero-torque conditions) and powerlaw (with and without cut-off)/low temperature Comptonization (Yadav et al 1999;Nobili et al 2000;Trudolyubov 2001;Klein-Wolt et al 2002;Lee et al 2002;Fuchs et al 2003;Rodriguez et al 2008Rodriguez et al , 2004Martocchia et al 2006;Middleton et al 2006;Ueda et al 2009) or thermal Comptonization of disc blackbody photons along with the presence of a strong nonthermal component/powerlaw tail using RXTE/PCA, RXTE/HEXTE (Pahari & Pal 2010;Done et al 2004;Naik et al 2002b) simultaneously with OSSE/CGRO observations (Zdziarski et al 2001;Rau & Greiner 2003), SUZAKU observations , BeppoSAX observations (Mineo et al 2012) and INTEGRAL observations (Rodriguez et al 2008). Sobolewska & Zyśki (2003) observe that although HS state spectra are dominated by soft thermal emission, it is complex in nature and can not be described by a standard thermal disc.…”

Section: Introductionmentioning

confidence: 99%

Interpreting the large amplitude X-ray variation of GRS 1915+105 and IGR J17091−3624 as modulations of an accretion disc

Pahari¹,

Misra²,

Mukherjee³

et al. 2013

Monthly Notices of the Royal Astronomical Society

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Using the flux resolved spectroscopy for the first time, we analyse the RXTE/PCA data of the black hole X-ray binaries GRS 1915+105 and IGR J17091−3624, when both sources show large amplitude, quasi-regular oscillations in 2.0−60.0 keV X-ray light curves ( similar to the κ and λ classes in GRS 1915+105). For different observations, we extract spectra during the peak (spectrally soft) and dip (spectrally hard) intervals of the oscillation, and find that their spectra are phenomenologically complex, requiring at least two distinct spectral components. Besides a thermal Comptonization component, we find that the disc emission is better modelled by an index-free multicolour disc blackbody component (p−free disc model) rather than that from a standard accretion disc. While the peak and dip spectra are complex, remarkably, their difference spectra constructed by treating dip spectra as the background spectra of the peak spectra, can be modelled as a single p−free disc component. Moreover, the variability at different time-scales and energy bands of the peak flux level is always greater than or equal to the variability of the dip flux level, which strengthens the possibility that the peak flux level may be due to an independent spectral component added to the dip one. Using joint spectral analysis of peak and dip spectra with a variable emission component, we verify that the variable component is consistent with p−free disc blackbody and its spectral parameters are similar to that found from the difference spectral analysis. In contrast, we show that for oscillations in the θ class where soft dips are observed, the difference spectra cannot be similarly fitted. Our result substantiates the standard hypothesis that the oscillations are due to the limit cycle behaviour of an unstable radiation pressure dominated inner disc. However, in this interpretation, the flux variation of the unstable disc can be several order of magnitudes as expected from some theoretical simulations and need not be fine tuned to match the factor of ∼ 10 variation seen between the peak and dip levels. (MP) days, makes GRS 1915+105 unique with respect to other micro-quasars. These drops are most prominent in κ, λ and ρ classes and they are simultaneous with spectral hardening by a couple of factors (Yadav et al. 1999;Belloni et al. 2000;Rao et al. 2000;Naik et al. 2002a).Several attempts have been made to model the spectra of such fluctuations by assuming that the energy spectra at the base/persistent flux level of the fluctuation are consistent with the low hard state (L bol /LEDD ∼ 0.05−0.2) while energy spectra at the peak flux level are consistent with

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“…Neilsen et al (2012) showed that about a third of all RXTE observations of GRS 1915+105 in the ρ-state show a single peak, 40% show a double peak and the rest show some intermediate shape. The oscillations in fitting parameters are similar to Neilsen et al (2011) and Mineo et al (2012) if we use the same models. The shapes, however, depend of the exact model used.…”

Section: The Continuummentioning

confidence: 68%

“…This suggested that the central region of the disk evaporates or becomes radiatively inefficient during the instability before refilling on a viscous timescale. This picture appeared to be supported by the spectral modeling of the different states (Belloni et al 1997(Belloni et al , 2000Mineo et al 2012). Uncertainties in disk atmosphere models (e.g., the density or the fraction of power dissipated in a corona) can, however, be important and may affect these inferred radius estimates significantly (e.g., Merloni et al 2000;Miller et al 2009).…”

Section: Introductionmentioning

confidence: 77%

Disk–wind Connection During the Heartbeats of GRS 1915+105

Zoghbi

Miller

King

et al. 2016

ApJ

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Disk and wind signatures are seen in the soft state of Galactic black holes, while the jet is seen in the hard state. Here we study the disk-wind connection in the ρ class of variability in GRS 1915+105 using a joint NuSTARChandra observation. The source shows 50 s limit cycle oscillations. By including new information provided by the reflection spectrumand using phase-resolved spectroscopy, we find that the change in the inner disk inferred from the blackbody emission is not matched by reflection measurements. The latter is almost constant, independent of the continuum model. The two radii are comparable only if the disk temperature color correction factor changes, an effect that could be due to the changing opacity of the disk caused by changes in metal abundances. The disk inclination is similar to that inferred from the jet axis, and oscillates by ∼10°. The simultaneous Chandra data show the presence of two wind components with velocities between 500 and 5000 km s −1 , and possibly two more with velocities reaching 20,000 km s −1 (∼0.06 c). The column densities are ∼5×10 22 cm −2 . An upper limit to the wind response time of 2 s is measured, implying a launch radius of <6×10 10 cm. The changes in wind velocity and absorbed flux require the geometry of the wind to change during the oscillations, constraining the wind to be launched from a distance of 290-1300 r g from the black hole. Both data sets support fundamental model predictions in which a bulge originates in the inner disk and moves outward as the instability progresses.

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The complex behaviour of the microquasar GRS 1915+105 in theρclass observed withBeppoSAX

Cited by 25 publications

References 51 publications

Disc–corona interaction in the heartbeat state of GRS 1915+105

Disc–corona interaction in the heartbeat state of GRS 1915+105

Interpreting the large amplitude X-ray variation of GRS 1915+105 and IGR J17091−3624 as modulations of an accretion disc

Disk–wind Connection During the Heartbeats of GRS 1915+105

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