Time delay between the optical and X-ray outbursts in the high-mass X-ray transient A0535+26/HDE245770

Giovannelli, F.; Бисноватый-Коган, Г. С.; Klepnev, A. S.

doi:10.1051/0004-6361/201220800

Cited by 4 publications

(4 citation statements)

References 39 publications

(87 reference statements)

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“…Time lag G.S.Bisnovatyi-Kogan Figure 1: Sketch of the accretion flow in a disk being picked up by a strong neutron star magnetic field [9].…”

Section: Pos(apcs2016)037mentioning

confidence: 99%

“…For a givenṀ in the flash, the value of T e f f is changing in time, while the wave of a largeṀ is moving to the star along the accretion disk [9], [8], [3]. The equation for the radius of the hot layer flash wave moving to the star is written as…”

Section: Calculation Of Time Lag In the Model Of Disk Accretion For Gmentioning

confidence: 99%

“…This sort of flush reaches the external part of the temporary accretion disk around the neutron star and moves to the hot central parts of the accretion disk and the neutron star's surface. The time necessary for this way is dependent on the turbulent viscosity in the accretion disk, as discussed in [9]. Behaviour of A0535+26/HDE245770 during the year 2014 was discussed in [8] and relationship ∆V mag vs I x was derived , predicting not only the arrival time of X-ray outbursts, but also its intensity I x .…”

Section: Introductionmentioning

confidence: 99%

“…A quantitative model have been constructed in [9] for explaining the time delay between optical and X-ray outbursts. The mechanism for explaining the X-ray -optical delay in A 0535+26/HDE 245770 is based on an enhanced mass flux propagation through the viscous accretion disk.…”

Section: Introductionmentioning

confidence: 99%

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Time lag in transient cosmic accreting sources

Бисноватый-Коган¹,

Giovannelli²

2018

Proceedings of Accretion Processes in Cosmic Sources — PoS(APCS2016)

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Models are developed for time lag between maxima of the source brightness in different wavelengths during a transient flash of luminosity connected with a short period of increase of the mass flux onto the central compact object. A simple formula is derived for finding the time delay among events in different wavelengths, valid in general for all disk accreting cosmic sources. In close binaries with accretion disks the time lag is connected with effects of viscosity defining a radial motion of matter in the accretion disk. In AGN flashes, the falling matter has a low angular momentum, and the time lag is defined by the free fall time to the gravitating center. The validity of these models is shown by means of several examples of galactic and extragalactic accreting sources.

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“…Time lag G.S.Bisnovatyi-Kogan Figure 1: Sketch of the accretion flow in a disk being picked up by a strong neutron star magnetic field [9].…”

Section: Pos(apcs2016)037mentioning

confidence: 99%

Section: Calculation Of Time Lag In the Model Of Disk Accretion For Gmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Time lag in transient cosmic accreting sources

Бисноватый-Коган¹,

Giovannelli²

2018

Proceedings of Accretion Processes in Cosmic Sources — PoS(APCS2016)

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Magnetorotational instability in decretion disks of critically rotating stars and the outer structure of Be and Be/X-ray disks

Krtička

Kurfürst

Krtičková

2014

A&A

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Context. Evolutionary models of fast-rotating stars show that the stellar rotational velocity may approach the critical speed. Critically rotating stars cannot spin up more, therefore they lose their excess angular momentum through an equatorial outflowing disk. The radial extension of such disks is unknown, partly because we lack information about the radial variations of the viscosity. Aims. We study the magnetorotational instability, which is considered to be the origin of anomalous viscosity in outflowing disks. Methods. We used analytic calculations to study the stability of outflowing disks submerged in the magnetic field. Results. The magnetorotational instability develops close to the star if the plasma parameter is large enough. At large radii the instability disappears in the region where the disk orbital velocity is roughly equal to the sound speed. Conclusions. The magnetorotational instability is a plausible source of anomalous viscosity in outflowing disks. This is also true in the region where the disk radial velocity approaches the sound speed. The disk sonic radius can therefore be roughly considered as an effective outer disk radius, although disk material may escape from the star to the insterstellar medium. The radial profile of the angular momentum-loss rate already flattens there, consequently, the disk mass-loss rate can be calculated with the sonic radius as the effective disk outer radius. We discuss a possible observation determination of the outer disk radius by using Be and Be/X-ray binaries.

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Time lag in transient cosmic accreting sources

Бисноватый-Коган

Giovannelli

2017

A&A

Self Cite

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Context. We develop models for time lag between the maxima of the source brightness in different wavelengths during a transient flash of luminosity that is connected with a short-period increase of the mass flux onto the central compact object. Aims. We derive a simple formula for finding the time delay among events in different wavelengths which is valid in general for all disk-accreting cosmic sources. We quantitatively also discuss a model for time-lag formation in active galactic nuclei (AGNs). Methods. In close binaries with accretion disks, the time lag is connected with effects of viscosity that define a radial motion of matter in the accretion disk. In AGN flashes, the infalling matter has a low angular momentum, and the time lag is defined by the free-fall time to the gravitating center. Results. We show the validity of these models by means of several examples of galactic and extragalactic accreting sources.

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Time delay between the optical and X-ray outbursts in the high-mass X-ray transient A0535+26/HDE245770

Cited by 4 publications

References 39 publications

Time lag in transient cosmic accreting sources

Time lag in transient cosmic accreting sources

Magnetorotational instability in decretion disks of critically rotating stars and the outer structure of Be and Be/X-ray disks

Time lag in transient cosmic accreting sources

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