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Illarionov, É. I.

doi:10.1023/a:1023912616665

Cited by 11 publications

(8 citation statements)

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“…The photons originating from the emitting region (hot spots or accretion column) are reprocessed partially. The photons experience ∼ τ 2 e scatterings on the average, where τe is the optical thickness (Ivanov 1969;Illarionov & Syunyaev 1972). The initial energy of photons will be reduced due to the recoil effect from E ≫ kTe to ∼ max(3kBTe, mec 2 /τ 2 e ), which leads to effective energy absorption by the accretion curtain (Syunyaev 1976).…”

Section: Interaction Of the Accretion Curtain With X-ray Photons In Nmentioning

confidence: 99%

Optically thick envelopes around ULXs powered by accreating neutron stars

Mushtukov

Suleimanov

Tsygankov

et al. 2017

Mon. Not. R. Astron. Soc.

105

175

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Magnetized neutron stars power at least some ultra-luminous X-ray sources. The accretion flow in these cases is interrupted at the magnetospheric radius and then reaches the surface of a neutron star following magnetic field lines. Accreting matter moving along magnetic field lines forms the accretion envelope around the central object. We show that, in case of high mass accretion rates 10 19 g s −1 the envelope becomes closed and optically thick, which influences the dynamics of the accretion flow and the observational manifestation of the neutron star hidden behind the envelope. Particularly, the optically thick accretion envelope results in a multi-color black-body spectrum originating from the magnetospheric surface. The spectrum and photon energy flux vary with the viewing angle, which gives rise to pulsations characterized by high pulsed fraction and typically smooth pulse profiles. The reprocessing of radiation due to interaction with the envelope leads to the disappearance of cyclotron scattering features from the spectrum. We speculate that the super-orbital variability of ultra-luminous X-ray sources powered by accreting neutron stars can be attributed to precession of the neutron star due to interaction of magnetic dipole with the accretion disc.

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Section: Interaction Of the Accretion Curtain With X-ray Photons In Nmentioning

confidence: 99%

Optically thick envelopes around ULXs powered by accreating neutron stars

Mushtukov

Suleimanov

Tsygankov

et al. 2017

Mon. Not. R. Astron. Soc.

105

175

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“…VT16 (Ti-3Al-5Mo-5V) is a two-phase ( )-metastable alloy hardenable by heat treatment including solution treatment, water quenching and ageing [1]. The alloy is capable of cold working after quenching [2,3].…”

Section: Introductionmentioning

confidence: 99%

Fracture surface analysis of a quenched (α+β)-metastable titanium alloy

Илларионов¹,

Stepanov²,

Демаков³

2017

AIP Conference Proceedings

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Abstract. Fracture surface analysis is conducted by means of SEM for VT16 titanium alloy specimens solution-treated at temperatures ranging from 700 to 875 °C, water-quenched and subjected to tensile testing. A cup and cone shape failure and dimple microstructure of the fracture surface indicates the ductile behavior of the alloy. Dimple dimensions correlated with the β-grain size of the alloy in quenched condition. The fracture area (namely, the size; the cup and cone shape) depends on the volume fraction of the primary α-phase in the quenched sample. However, the fracture surface changes considerably when the strain-induced β-αʺ-transformation takes place during tensile testing, resulting in the increase of alloy ductility.

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“…It is also important to note that radiation in harder parts of the spectrum could originate, in principle, from the processes not considered in the Paper, such as the Compton scattering between synchrotron photons and thermal electrons and magnetic reconnection events leading to formation of a tail of high energy non-thermal electrons. However, the y-parameter defined as y = ∞ R min dRσ T h n k B Te mec 2 , where σ T h is the Thomson cross section (Illarionov & Syunyaev (1972)) is extremely small in our case, order of ∼ 10 −5 telling that the Compton effects may be negligible. The possible contribution of non-thermal electrons was considered in Beskin & Karpov (2005), who assumed that a fraction order of 0.1 of released potential energy of infalling gas is transferred to relativistic electrons with a power-law distribution over their energy.…”

Section: The Possibility Of Radiation Emission In Other Parts Of Specmentioning

confidence: 67%

Search for isolated Galactic Centre stellar mass black holes in the IR and sub-mm range

Ivanov

Lukash

Пилипенко

et al. 2019

Monthly Notices of the Royal Astronomical Society

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We investigate a possibility to find an accreting isolated black hole (IBH) with mass 1 − 100M within Central Galactic Molecular Zone (CMZ) in the submillimetre and IR spectral range with help of planned space observatories James Webb Space Telescope (JWST) and Millimetron (MM). We assume the spherical mode of accretion. We develop the simplest possible quantitative model of the formation of radiation spectrum in this range due to synchrotron emission and show that it fully agrees with the more complicated model of Ipser and Price 1982 for expected values of accretion rate.If a substantial fraction of LIGO events was caused by merger of primordial black holes, the JWST would be able to find them provided that there is a cusp in distribution of dark matter in the Galaxy and that the accretion efficiency parameter λ defined as the ratio of accretion rate onto IBH to its Bondi-Hoyle-Lyttleton value is larger than ∼ 10 −2 . A comparable amount of IBHs is also predicted by recent models of their formation due to stellar evolution. MM capabilities are hampered by the effect of confusion due to distant submillimetre galaxies, but it can also be used for such purposes if the confusion effect is properly dealt with. In case of efficient accretion with λ ∼ 1, both instruments could detect IBHs even when their number densities are as low as 10 −6 pc −3 .

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Cited by 11 publications

References 0 publications

Optically thick envelopes around ULXs powered by accreating neutron stars

Optically thick envelopes around ULXs powered by accreating neutron stars

Fracture surface analysis of a quenched (α+β)-metastable titanium alloy

Search for isolated Galactic Centre stellar mass black holes in the IR and sub-mm range

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