Power spectral distribution of the BL Lacertae object S5 0716+714

Mocanu, Gabriela; Marcu, A.

doi:10.1002/asna.201111645

Cited by 9 publications

(12 citation statements)

References 39 publications

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“…This is a consequence of the fact that SOC may be an underlying principle in Nature, as the initial intuition of [5] stated. Examples in astrophysics include organization of plasma in accretion discs [28] to explain observational data such as those discussed in [29], axion clouds around black hole [30], solar flares [9,14,17,21]. [39] have analyzed GRB X-Ray data, and they did find that all observational results can be fitted into a framework based on a stochastic pulse avalanche model running in a near-critical regime.…”

Section: Introductionmentioning

confidence: 99%

Self organized criticality in an one dimensional magnetized grid. Application to GRB X-ray afterglows

Harkó

Mocanu

Stroia

2015

Astrophys Space Sci

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A simplified one dimensional grid is used to model the evolution of magnetized plasma flow. We implement diffusion laws similar to those so-far used to model magnetic reconnection with Cellular Automata. As a novelty, we also explicitly superimpose a background flow. The aim is to numerically investigate the possibility that Self-Organized Criticality appears in a one dimensional magnetized flow. The cellular automaton's cells store information about the parameter relevant to the evolution of the system being modelled. Under the assumption that this parameter stands for the magnetic field, the magnetic energy released by one volume during one individual relaxation event is also computed. Our results show that indeed in this system Self-Organized Criticality is established. The possible applications of this model to the study of the X-ray afterglows of GRBs is also briefly considered.

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Section: Introductionmentioning

confidence: 99%

Self organized criticality in an one dimensional magnetized grid. Application to GRB X-ray afterglows

Harkó

Mocanu

Stroia

2015

Astrophys Space Sci

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“…Comparison with the statistical properties of observational data for a BL Lac, e.g. analysed in [24], is good.…”

Section: Resultsmentioning

confidence: 77%

Appearance of an accretion disc perturbed by fractional Brownian Motion density

Mocanu

Magyar

Pardi

et al. 2014

Monthly Notices of the Royal Astronomical Society

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This paper aims to investigate/map the effects that perturbations applied to an accretion disk might produce on the registered Light Curves (LC). The case of accretion disks around supermassive active black holes (AGNs) is studied with the goal to explain some of the statistical properties of the observed IntraDay Variability (IDV). The region producing optical IDV is perturbed by allowing it to develop a mass density of a fractional Brownian Motion-like type. The light curves and spectral slopes are calculated and compared to observational data for different Hurst parameters. The spectral slopes of the simulated light curves vary in the range (0.4, 2.5). The agreement with observational data shows that a magnetized disk subjected to stochastic perturbations can produce some of the features observed in the light curves.

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“…, a PSD analysis performed on IDV data in the BVRI bands has shown that α varied between approximately −1.5 and −2.7 for that set of data [51].…”

Section: Comparison With Agn Idv Datamentioning

confidence: 94%

Generalized Langevin equation with colored noise description of the stochastic oscillations of accretion disks

2014

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We consider a description of the stochastic oscillations of the general relativistic accretion disks around compact astrophysical objects interacting with their external medium based on a generalized Langevin equation with colored noise and on the fluctuation-dissipation theorems. The former accounts for the general memory and retarded effects of the frictional force. The presence of the memory effects influences the response of the disk to external random interactions, and it modifies the dynamical behavior of the disk, as well as the energy dissipation processes. The generalized Langevin equation of the motion of the disk in the vertical direction is studied numerically, and the vertical displacements, velocities, and luminosities of the stochastically perturbed disks are explicitly obtained for both the Schwarzschild and the Kerr cases. The power spectral distribution of the disk luminosity is also obtained. As a possible astrophysical application of the formalism we investigate the possibility that the intra-day variability of the active galactic nuclei may be due to the stochastic disk instabilities. The perturbations due to colored/nontrivially correlated noise induce a complicated disk dynamics, which could explain some astrophysical observational features related to disk variability.

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Power spectral distribution of the BL Lacertae object S5 0716+714

Cited by 9 publications

References 39 publications

Self organized criticality in an one dimensional magnetized grid. Application to GRB X-ray afterglows

Self organized criticality in an one dimensional magnetized grid. Application to GRB X-ray afterglows

Appearance of an accretion disc perturbed by fractional Brownian Motion density

Generalized Langevin equation with colored noise description of the stochastic oscillations of accretion disks

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