Advection‐dominated Accretion: Global Transonic Solutions

Chen, Xingming; Abramowicz, Marek A.; Lasota, Jean–Pierre

doi:10.1086/303592

Cited by 107 publications

(112 citation statements)

References 22 publications

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“…Thus, the integrated pressure has the maximum at r 7 r s . These features are also seen in previous solutions (Chen et al 1997;Nakamura et al 1997;Narayan et al 1997). Therefore, our solutions are consistent with numerical solutions found in other studies.…”

Section: Dynamical Structure Of Flows Without High-energy Particlessupporting

confidence: 93%

“…The advectiondominated accretion flow (ADAF) is a solution realized when the mass accretion rates are sufficiently smaller than the Eddington accretion rates (Narayan & Yi 1994). Many calculations about the global structure of ADAF were performed in the late 1990s (e.g., Narayan & Yi 1995;Chen et al 1997;Manmoto et al 1997). ADAF is so hot and tenuous that the plasma in this flow becomes collisionless, which allows the particles in the flow to have a non-thermal distribution (Mahadevan & Quataert 1997).…”

Section: Introductionmentioning

confidence: 99%

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Effects of High-Energy Particles on Accretion Flows Onto a Supermassive Black Hole

Kimura

Toma

Takahara

2014

ApJ

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We study the effects of high-energy particles (HEPs) on the accretion flows onto a supermassive black hole and luminosities of escaping particles such as protons, neutrons, gamma rays, and neutrinos. We formulate a onedimensional model of the two-component accretion flow consisting of thermal particles and HEPs, supposing that some fraction of the released energy is converted to the acceleration of HEPs. The thermal component is governed by fluid dynamics while the HEPs obey the moment equations of the diffusion-convection equation. By solving the time evolution of these equations, we obtain advection-dominated flows as the steady state solutions. The effects of the HEPs on the flow structures turn out to be small even if the pressure of the HEPs dominates over the thermal pressure. For a model in which the escaping protons take away almost all the energy released, the HEPs have a large enough influence to make the flow have a Keplerian angular velocity at the inner region. We calculate the luminosities of the escaping particles for these steady solutions. The escaping particles can extract the energy from about 10 −4Ṁ c 2 to 10 −2Ṁ c 2 , whereṀ is the mass accretion rate. The luminosities of the escaping particles depend on parameters such as the injection Lorentz factors, the mass accretion rates, and the diffusion coefficients. We also discuss some implications on the relativistic jet production by the escaping particles.

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Section: Dynamical Structure Of Flows Without High-energy Particlessupporting

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Effects of High-Energy Particles on Accretion Flows Onto a Supermassive Black Hole

Kimura

Toma

Takahara

2014

ApJ

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“…The ion temperature in the disc is found to be always sub-virial, Ti < ∼ 2 × 10 11 K (e.g. S76; Chen et al 1997). The strongest magnetic field is achieved in an inner region, where the plasma density is the largest.…”

Section: The Role Of Magnetic Fieldsmentioning

confidence: 99%

Broad-band X-ray/γ-ray spectra and binary parameters of GX 339–4 and their astrophysical implications

Zdziarski¹,

Poutanen²,

Mikołajewska³

et al. 1998

Monthly Notices of the Royal Astronomical Society

197

217

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We present X-ray/γ-ray spectra of the binary GX 339-4 observed in the hard state simultaneously by Ginga and CGRO OSSE during an outburst in 1991 September. The Ginga X-ray spectra are well represented by a power law with a photon spectral index of Γ ≃ 1.75 and a Compton reflection component with a fluorescent Fe Kα line corresponding to a solid angle of an optically-thick, ionized, medium of ∼ 0.4×2π. The OSSE data ( 50 keV) require a sharp high-energy cutoff in the power-law spectrum. The broad-band spectra are very well modelled by repeated Compton scattering in a thermal plasma with an optical depth of τ ∼ 1 and kT ≃ 50 keV. We also study the distance to the system and find it to be > ∼ 3 kpc, ruling out earlier determinations of ∼ 1 kpc. Using this limit, the observed reddening and the orbital period, we find the allowed range of the mass of the primary is consistent with it being a black hole.We find the data are incosistent with models of either homogenous or patchy coronae above the surface of an accretion disc. Rather, they are consistent with the presence of a hot inner hot disc with the viscosity parameter of α ∼ 1 accreting at a rate close to the maximum set by advection. The hot disc is surrounded by a cold outer disc, which gives rise to the reflection component and a soft X-ray excess, also present in the data. The seed photons for Comptonization are unlikely to be due to thermal synchrotron radiation. Rather, they are supplied by the outer cold disc and/or cold clouds within the hot disc. e ± pair production is negligible if electrons are thermal. The hot disc model, which scaled parameters are independent of the blackhole mass, is supported by the similarity of the spectrum of GX 339-4 to those of other black-hole binaries and Seyfert 1s. On the other hand, their spectra in the soft γ-ray regime are significantly harder than those of weakly-magnetized neutron stars. Based on this difference, we propose that the presence of broad-band spectra corresponding to thermal Comptonization with kT > ∼ 50 keV represents a black-hole signature.

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“…Various authors have described this cases the sub-and super-Eddington flows. Models suggest a flow deformation, such as: rotation of the velocity vector for radial advection, see, Beloborodov (1998), Bisnovatyi-Kogan (1998 Bisnovatyi-Kogan& Lovelace (2002), Chen et al (1997), Narayan et al (1997), Narayan & Yi (1995); or orbital advection for low-magnetic discs, where orbital speed vector is added to the Keplerian velocity see Fabian et al (2012). At these types of advection action of ∂v i /∂t-component is ignored.…”

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confidence: 99%

Book of Proceedings: Ninth Workshop, Sunny Beach, Bulgaria, May 30 - June 3, 2017

2017

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E Ed di it to or rs s: Katya Georgieva, Boian Kirov, Dimitar DanovProceedings of Ninth Workshop "Solar Influences on the Magnetosphere, Ionosphere and Atmosphere" Sunny Beach, Bulgaria, May 30 ÷ June 3, 2017 C C O O N N T T E E N N T T Sun and Solar Activity Podgorny I.M., Podgorny A.I. Diagnostics of Solar Flares by Analyzing the SpectralLine Emission of Highly Ionized Iron 01 Kalinichenko N., Olyak M., Konovalenko A., Brazhenko A., Ivantishin O., Lytvynenko O., Bubnov I., Yerin S., Kuhai N., Romanchuk O. A method for reconstructing the solar-wind stream structure beyond Earths orbit 07 Melnik V., Brazhenko A., Dorovskyy V., Rucker H., Panchenko M., Frantsuzenko A., Shevchuk M.. Decameter type IV burst associated with behind-limb CME observed on November 7, 2013 13 Miteva R., Samwel S.W., Krupar V. Solar radio burst emission from protonproducing flares and coronal mass ejections 19 Veselovsky I., Kaportseva K., Lukashenko A. Eight types of the solar wind and their origins 24 Stanislavsky A.A., Konovalenko A.A., Koval A.A., Volvach Ya.S.. An upgrade of the UTR-2 radio telescope to a multifrequency radio heliograph I., Gromov S.V., Kleimenova N.G., Dremukhina L.A.. Role of the IMF |Bz|/|By| in the appearance of the daytime high-latitude magnetic bays 103Proceedings of Ninth Workshop "Solar Influences on the Magnetosphere, Ionosphere and Atmosphere" Sunny Beach, Bulgaria, May 30 ÷ June 3, 2017 IV C C O O N N T T E E N N T T Solar Influences on the Lower Atmosphere and Climate Author index 133Proceedings of Ninth Workshop "Solar Influences on the Magnetosphere, Ionosphere and Atmosphere" Sunny Beach, Bulgaria, May 30 -June 3, 2017 Topic: Sun and Solar Activity Abstract.The photos of the pre-flare development observed in the spectral lines of highly ionized iron (SDO AIA apparatus) indicate the energy accumulation for a flare in the corona in the pre-flare local (about 1010 cm) high temperature structure. The pre-flare structures in the corona are observed in UV spectral lines of ions FeXXIV, FeXXIII, FeXVIII several hours before big solar flares. During a flare the emission of the UV spectral lines in the corona are increased explosively. These phenomena can be used for prediction of solar cosmic rays. Information obtained from the worldwide neutron monitor network and measurements on GOES spacecraft demonstrates unambiguously that solar cosmic rays are generated in solar flares. These phenomena are well described by the solar flare electrodynamical model, created on the basis of the observational data and the numerical magnetohydrodynamic simulation using the initial and boundary conditions, taken from the active regions observation before the flare. It is impossible to exclude that the similar mechanism of particle acceleration is responsible for galactic cosmic rays generation. Now all published mechanisms of cosmic ray generation are based on unproven assumptions. These assumptions are not confirmed by longterm observations. With the modern concept of cosmic rays, a fundamentally important qu...

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Advection‐dominated Accretion: Global Transonic Solutions

Cited by 107 publications

References 22 publications

Effects of High-Energy Particles on Accretion Flows Onto a Supermassive Black Hole

Effects of High-Energy Particles on Accretion Flows Onto a Supermassive Black Hole

Broad-band X-ray/γ-ray spectra and binary parameters of GX 339–4 and their astrophysical implications

Book of Proceedings: Ninth Workshop, Sunny Beach, Bulgaria, May 30 - June 3, 2017

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