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

Pahari, Mayukh; Misra, Ranjeev; Mukherjee, Arunava; Yadav, J. S.; Pandey, S. K.

doi:10.1093/mnras/stt1732

Cited by 12 publications

(11 citation statements)

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“…Using the rate resolved spectroscopy, we got A&A 569, A33 (2014) the spectral parameters from different rate bands. Following Pahari et al (2013a), we obtained the spectral parameters from the peak and dip, respectively. For those between the peak and dip, we obtained the spectral parameters from the ascending and descending parts, respectively.…”

Section: Observations and Data Analysismentioning

confidence: 99%

“…All the energy spectra were fit in the 3.0−30.0 keV band using XSPEC version 12.7. The energy spectra have two main components: thermal and non-thermal (Belloni et al 1997b;Pahari et al 2013a). Different models can be used to well describe the two components (Pahari et al 2013a).…”

Section: Observations and Data Analysismentioning

confidence: 99%

“…The energy spectra have two main components: thermal and non-thermal (Belloni et al 1997b;Pahari et al 2013a). Different models can be used to well describe the two components (Pahari et al 2013a). Following Pahari et al (2013a), we fit these spectra with different disk models, such as diskbb or diskpbb in addition to the powerlaw model.…”

Section: Observations and Data Analysismentioning

confidence: 99%

“…Different models can be used to well describe the two components (Pahari et al 2013a). Following Pahari et al (2013a), we fit these spectra with different disk models, such as diskbb or diskpbb in addition to the powerlaw model. Some spectra required a Gaussian for good fit.…”

Section: Observations and Data Analysismentioning

confidence: 99%

“…The loop-like behaviors need to be studied to resolve the issue of whether there are differences in physical origin between different classes. Using the rate-resolved spectroscopy, Pahari et al (2013a) extracted energy spectra during the peak and dip intervals of the different classes and found that their spectra are phenomenologically complex. We performed more refined spectral analysis for different classes in IGR J17091−3624.…”

Section: Introductionmentioning

confidence: 99%

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The variability classes in IGR J17091–3624 during the 2011 outburst

Zhang

et al. 2014

A&A

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Section: Observations and Data Analysismentioning

confidence: 99%

Section: Observations and Data Analysismentioning

confidence: 99%

Section: Observations and Data Analysismentioning

confidence: 99%

Section: Observations and Data Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The variability classes in IGR J17091–3624 during the 2011 outburst

Zhang

et al. 2014

A&A

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Chaotic and stochastic processes in the accretion flows of the black hole X-ray binaries revealed by recurrence analysis

Suková

Grzȩdzielski

Janiuk

2016

A&A

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Aims. Both the well known microquasar GRS 1915+105, as well as its recently discovered analogue, IGR J17091-3624, exhibit variability that is characteristic of a deterministic chaotic system. Their specific kind of quasi-periodic flares that are observed in some states is intrinsically connected with the global structure of the accretion flow, which are governed by the nonlinear hydrodynamics. One plausible mechanism that is proposed to explain this kind of variability is the thermal-viscous instability that operates in the accretion disk. The purely stochastic variability that occurs because of turbulent conditions in the plasma, is quantified by the power density spectra and appears in practically all types of sources and their spectral states. Methods. We pose a question as to whether these two microquasars are one of a kind, or if the traces of deterministic chaos, and hence the accretion disk instability, may also be hidden in the observed variability of other sources. We focus on the black hole X-ray binaries that accrete at a high rate and are, therefore, theoretically prone to the development of radiation pressure-induced instability. To study the nonlinear behaviour of the X-ray sources and distinguish between the chaotic and stochastic nature of their emission, we propose a novel method, which is based on recurrence analysis. Widely known in other fields of physics, this powerful method is used here for the first time in an astrophysical context. We estimate the indications of deterministic chaos quantitatively, such as the Rényi's entropy for the observed time series, and we compare them with surrogate data. Results. Using the observational data collected by the RXTE satellite, we reveal the oscillations pattern and the observable properties of six black hole systems. For five of them, we confirm the signatures of deterministic chaos being the driver of their observed variability. Conclusions. We test the method and confirm the deterministic nature of variability in the microquasars GRS 1915+105 and IGR J17091-3624. Furthermore, we also find significant traces of nonlinear dynamics in three other sources: GX 339-4, XTE J1550-564 and GRO J1655-40, particularly in the disk-dominated soft state, as well as in the intermediate states at the rising and declining phase of the outburst. Only for the source XTE J1650-500 no observation with such variability pattern was found. This is possibly due to the global accretion rate in this source being too small for the limit-cycle instability to develop.

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An X-ray flaring event and a variable soft X-ray excess in the Seyfert LCRS B040659.9–385922 as detected with eROSITA

Krishnan,

Markowitz,

Krumpe

et al. 2024

A&A

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Extreme continuum variability in extragalactic nuclear sources can indicate extreme changes in accretion flows onto supermassive black holes. We explore the multiwavelength nature of a continuum flare in the Seyfert LCRS B040659.9$-$385922. The all-sky X-ray surveys conducted by the Spectrum Roentgen Gamma (SRG)/extended ROentgen Survey with an Imaging Telescope Array (eROSITA) showed that its X-ray flux increased by a factor of roughly five over six months, and concurrent optical photometric monitoring with the Asteroid Terrestrial-impact Last Alert System (ATLAS) showed a simultaneous increase. We complemented the eROSITA and ATLAS data by triggering a multiwavelength follow-up monitoring program (X-ray Multi-Mirror Mission: XMM-Newton Neutron star Interior Composition Explorer: NICER; optical spectroscopy) to study the evolution of the accretion disk, broad-line region, and X-ray corona. During the campaign, X-ray and optical continuum flux subsided over roughly six months. Our campaign includes two XMM-Newton observations, one taken near the peak of this flare and the other taken when the flare had subsided. The soft X-ray excess in both XMM-Newton observations was power law-like (distinctly nonthermal). Using a simple power law, we observed that the photon index of the soft excess varies from a steep value of $ 2.7$ at the flare peak to a relatively flatter value of $ 2.2$ as the flare subsided. We successfully modeled the broadband optical/UV/X-ray spectral energy distribution at both the flare peak and post-flare times with the AGNSED model, incorporating thermal disk emission into the optical/UV and warm thermal Comptonization in the soft X-rays. The accretion rate falls by roughly 2.5, and the radius of the hot Comptonizing region increases from the flaring state to the post-flare state. Additionally, from the optical spectral observations, we find that the broad He ii lambda 4686 emission line fades significantly as the optical/UV/X-ray continuum fades, which could indicate a substantial flare of disk emission above 54 eV. We also observed a redshifted broad component in the H$ beta $ emission line that is present during the high flux state of the source and disappears in subsequent observations. A sudden strong increase in the local accretion rate in this source manifested itself via an increase in accretion disk emission and in thermal Comptonized emission in the soft X-rays, which subsequently faded. The redshifted broad Balmer component could be associated with a transient kinematic component distinct from that comprising the rest of the broad-line region.

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

Cited by 12 publications

References 60 publications

The variability classes in IGR J17091–3624 during the 2011 outburst

The variability classes in IGR J17091–3624 during the 2011 outburst

Chaotic and stochastic processes in the accretion flows of the black hole X-ray binaries revealed by recurrence analysis

An X-ray flaring event and a variable soft X-ray excess in the Seyfert LCRS B040659.9–385922 as detected with eROSITA

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