QPO as the Rosetta Stone for understanding black hole accretion

Abramowicz, Marek A.

doi:10.1002/asna.200510413

Cited by 36 publications

(40 citation statements)

References 20 publications

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“…Nevertheless, the relationship between Ṁ and L outflow is still an open question(e.g., Beckmann & Shrader 2012), which we will continue to study in future work. We note that Abramowicz & Kluźniak (2001), Abramowicz (2005), and references therein suggested that QPOs ratiocould represent oscillations occurring at different radii in the inner disk, which is also consistent with our findings. In future work, we plan to explore the stable region to search for the Z-Mode, the Figure 20.…”

Section: Astrophysical Implications Of Qpos In Regions Of Instabilitysupporting

confidence: 93%

“…In this sense, we are reexamining the original Chakrabarti (1989)adiabatic accretion flow with isothermal shock instability problem, since this instability problem is still unresolved. We will briefly discuss the fundamental parameters that allow us to determine the diskshock structures, and we refer the readers to the previous series of papers by Le & Becker (2004, 2005 for further details.…”

Section: Introductionmentioning

confidence: 99%

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Standing Shock Instability in Advection-Dominated Accretion Flows

Wood

Wolff

et al. 2016

ApJ

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Depending on the values of the energy and angular momentum per unit mass in the gas supplied at large radii, inviscid advection-dominated accretion flows can display velocity profiles with either preshock deceleration or preshock acceleration. Nakayama has shown that these two types of flow configurations are expected to have different stability properties. By employing the Chevalier & Imamura linearization method and the Nakayama instability boundary conditions, we discover that there are regions of parameterspace where disks/shocks with outflows can be stable or unstable. In regions of instability, we find that preshock deceleration is always unstable to the zeroth mode with zero frequency of oscillation, but is always stable to the fundamental mode and overtones. Furthermore, we also find that preshock acceleration is always unstable to the zeroth modeand that the fundamental mode and overtones become increasingly less stable as the shock location moves away from the horizon when the disk half-height expands above ∼12 gravitational radii at the shock radius. In regions of stability, we demonstrate the zeroth mode to be stable for the velocity profiles that exhibit preshock acceleration and deceleration. Moreover, for models that are linearly unstable, our model suggests the possible existence of quasiperiodic oscillations (QPOs) with ratios 2:3 and 3:5. These ratios are believed to occur in stellar and supermassive black hole candidates, for example, in GRS 1915+105 and Sgr A * , respectively. We expect that similar QPO ratios also exist in regions of stable shocks.

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Section: Astrophysical Implications Of Qpos In Regions Of Instabilitysupporting

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Standing Shock Instability in Advection-Dominated Accretion Flows

Wood

Wolff

et al. 2016

ApJ

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“…This suggestion was developed by them and collaborators into the ''QPO resonance model.'' The model uses the theory of small nonlinear oscillations (e.g., Nayfeh & Mook 1979) and attempts to explain many observational properties of QPOs in X-ray binaries by deriving them directly from the differential equations that describe two weakly coupled, nonlinear oscillators (for more information, see the collection of reviews in Abramowicz [2005]), r þ (! r ) 2 r ¼ X r (r; ṙ; z; ż); z þ (!…”

Section: Introductionmentioning

confidence: 99%

Epicyclic Oscillations of Fluid Bodies: Newtonian Nonslender Torus

Blaes

Šrámková

Abramowicz

et al. 2007

ApJ

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We study epicyclic oscillations of fluid tori around black holes (in the Paczyński-Wiita potential) and derive exact analytic expressions for their radial and vertical eigenfrequencies r and z to second-order accuracy in the width of the torus. We prove that pressure effects make the eigenfrequencies smaller than those for free particles. However, the particular ratio z / r ¼ 3/2, which is important for the theory of high-frequency quasi-periodic oscillations (QPOs), occurs when the fluid tori epicyclic frequencies r and z are about 15% higher than the ones corresponding to free particles. Our results therefore suggest that previous estimates of black hole spins from QPOs have produced values that are too high.

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“…Other alternative possible mechanisms for QPOs in blazars on IDV timescales can also have a disk origin or can arise from relativistic jets. The former class includes small epicyclic deviations in both radial and vertical directions from exact planar motions within a thin accretion disk (e.g., [141]) and trapped pulsational modes within a disk (e.g., [123,142]). Using the detailed explanation of [142], one can also get the BH mass of the blazar.…”

Section: Quasi Periodic Oscillations In Intra-day Time Series Multi-wmentioning

confidence: 99%

Multi-Wavelength Intra-Day Variability and Quasi-Periodic Oscillation in Blazars

Gupta

2017

Galaxies

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Abstract:We reviewed multi-wavelength blazars variability and detection of quasi-periodic oscillations on intra-day timescales. The variability timescale from a few minutes to up to less than a days is commonly known as intra-day variability. These fast variations are extremely useful to constrain the size of the emitting region, black hole mass estimation, etc. It is noticed that in general, blazars show intra-day variability in the complete electromagnetic spectrum. However, some classes of blazars either do not show or show very little intra-day variability in a specific band of the electromagnetic spectrum. Blazars show rarely quasi-periodic oscillations in time series data in optical and X-ray bands. Other properties and emission mechanisms of blazars are also briefly discussed.

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QPO as the Rosetta Stone for understanding black hole accretion

Cited by 36 publications

References 20 publications

Standing Shock Instability in Advection-Dominated Accretion Flows

Standing Shock Instability in Advection-Dominated Accretion Flows

Epicyclic Oscillations of Fluid Bodies: Newtonian Nonslender Torus

Multi-Wavelength Intra-Day Variability and Quasi-Periodic Oscillation in Blazars

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