New Spectral State of Supercritical Accretion Flow with Comptonizing Outflow

Kawashima, Tomohisa; Ohsuga, Ken; Mineshige, Shin; Heinzeller, Dominikus; Takabe, H.; Matsumoto, Ryoji

doi:10.1093/pasj/61.4.769

Cited by 52 publications

(62 citation statements)

References 52 publications

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“…Model M6 would be like many existing radiative transfer simulations (Fragile et al 2012;Jiang et al 2014a;Fragile et al 2014;Takahashi et al 2016) except those by Fragile & Meier (2009) ;Kawashima et al (2009);Jiang et al (2014b) and ourselves McKinney et al 2014).…”

Section: Modelsmentioning

confidence: 99%

“…We account for energy exchange via Comptonization in the softphoton limit of Kompaneets equation, which we implement in a similar way to that described in Kawashima et al (2009). For a general temperature, using the result given in equation ( , which is consistent with the frequency-integrated energy-weighted Kompaneets equation and is valid for a BE distribution with any chemical potential.…”

Section: E2 Thermal Comptonization Via Kompaneets Scatteringmentioning

confidence: 99%

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Double Compton and Cyclo-Synchrotron in Super-Eddington Discs, Magnetized Coronae, and Jets

McKinney

Chluba

Wielgus

et al. 2017

Mon. Not. R. Astron. Soc.

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We present an extension to the general relativistic radiation magnetohydrodynamic code HARMRAD to account for emission and absorption by thermal cyclo-synchrotron, double Compton, bremsstrahlung, low-temperature OPAL opacities as well as Thomson and Compton scattering. We approximate the radiation field as a Bose-Einstein distribution and evolve it using the radiation number-energy-momentum conservation equations in order to track photon hardening. We perform various simulations to study how these extensions affect the radiative properties of magnetically-arrested disks accreting at Eddington to super-Eddington rates. We find that double Compton dominates bremsstrahlung in the disk within a radius of r ∼ 15r g (gravitational radii) at a hundred times the Eddington accretion rate, and within smaller radii at lower accretion rates. Double Compton and cyclo-synchrotron regulate radiation and gas temperatures in the corona, while cyclo-synchrotron regulates temperatures in the jet. Interestingly, as the accretion rate drops to Eddington, an optically thin corona develops whose gas temperature of T ∼ 10 9 K is ∼ 100 times higher than the disk's black body temperature. Our results show the importance of double Compton and synchrotron in super-Eddington disks, magnetized coronae, and jets.

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Section: Modelsmentioning

confidence: 99%

Section: E2 Thermal Comptonization Via Kompaneets Scatteringmentioning

confidence: 99%

Double Compton and Cyclo-Synchrotron in Super-Eddington Discs, Magnetized Coronae, and Jets

McKinney

Chluba

Wielgus

et al. 2017

Mon. Not. R. Astron. Soc.

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show abstract

“…We adopt the α prescription of viscosity (Shakura & Sunyaev 1973) and set α = 0.1. Basic equations and numerical methods to solve the radiation hydrodynamic equations are the same as in Kawashima et al (2009), and they are summarized in Appendix A.…”

Section: Radiation Hydrodynamic Simulations Of Supercritical Accretiomentioning

confidence: 99%

“…We improve on the investigation by Kawashima et al (2009) by using a larger computational domain 2r s r 1000r s and 0 θ π/2, and a higher resolution (N r , N θ ) = (192,192). We assume azimuthal symmetry and mirror symmetry with respect to the equatorial plane.…”

Section: Radiation Hydrodynamic Simulations Of Supercritical Accretiomentioning

confidence: 99%

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Comptonized Photon Spectra of Supercritical Black Hole Accretion Flows With Application to Ultraluminous X-Ray Sources

Kawashima

Ohsuga

Mineshige

et al. 2012

ApJ

120

140

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Radiation spectra of supercritical black hole accretion flows are computed using a Monte Carlo method by postprocessing the results of axisymmetric radiation hydrodynamic simulations. We take into account thermal/bulk Comptonization, free-free absorption, and photon trapping. We found that a shock-heated region (∼10 8 K) appears at the funnel wall near the black hole where the supersonic inflow is reflected by the centrifugal barrier of the potential. Both thermal and bulk Comptonization significantly harden photon spectra although most of the photons upscattered above 40 keV are swallowed by the black hole due to the photon trapping. When the accretion rate onto the black hole isṀ2 , where L E is the Eddington luminosity, the spectrum has a power-law component which extends up to ∼10 keV by upscattering of photons in the shock-heated region. In higher mass accretion rates, the spectra roll over around 5 keV due to downscattering of the photons by cool electrons in the dense outflow surrounding the jet. Our results are consistent with the spectral features of ultraluminous X-ray sources, which typically show either a hard power-law component extending up to 10 keV or a rollover around 5 keV. We found that the spectrum of NGC 1313 X-2 is quite similar to the spectrum numerically obtained for high accretion rate2 ) source observed with low viewing angle (i = 10Our numerical results also demonstrate that the face-on luminosity of supercritically accreting stellar mass black holes (10 M ) can significantly exceed 10 40 erg s −1 .

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Supercritical accretion and ULXs

Mineshige

Ohsuga

2011

Astron Nachr

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Supercritical (or super-Eddington) accretion seems to occur in various black hole objects, including microquasars and ultra-luminous X-ray sources. We, here, elucidate the theory of supercritical accretion flow based on our two-dimensional (2-D) global radiation-hydrodynamic (RHD) and radiation-magnetohydrodynamic (RMHD) simulations. We first confirm that there is practically no limit to the accretion rate onto black holes. We then discuss several noteworthy observable features of the supercritical flow; that is, mild beaming, relativistic, collimated outflow, and inverse-Compton scattering spectra by optically thick outflow. For face-on observers the maximum apparent (isotropic) luminosities of ∼ 22LE (with LE being the Eddington luminosity) can be achieved for the mass supply rate of ∼ 50LE/c 2 . Even larger isotropic luminosities are possible for higher mass supply rates. For edge-on observers, conversely, the apparent luminosity will be much less. It will be even lower, if the the innermost bright part of the disk is obscured by the outer part. High velocity (> 0.5c) jet accelerated by radiation-pressure force and collimated by Lorentz force is also expected. We expect large kinetic luminosity, ∼ 0.1LE, and high mass outflow rate, ∼ 10LE/c 2 . This may account for large ionizing nebulae around ULXs.

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New Spectral State of Supercritical Accretion Flow with Comptonizing Outflow

Cited by 52 publications

References 52 publications

Double Compton and Cyclo-Synchrotron in Super-Eddington Discs, Magnetized Coronae, and Jets

Double Compton and Cyclo-Synchrotron in Super-Eddington Discs, Magnetized Coronae, and Jets

Comptonized Photon Spectra of Supercritical Black Hole Accretion Flows With Application to Ultraluminous X-Ray Sources

Supercritical accretion and ULXs

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