Compton scattering opacities in a partially degenerate electron plasma at high temperatures

We present a numerical method which evolves a two-temperature, magnetized, radiative, accretion flow around a black hole, within the framework of general relativistic radiation magnetohydrodynamics. As implemented in the code KORAL, the gas consists of two subcomponents -ions and electrons -which share the same dynamics but experience independent, relativistically consistent, thermodynamical evolution. The electrons and ions are heated independently according to a prescription from the literature for magnetohydrodynamical turbulent dissipation. Energy exchange between the particle species via Coulomb collisions is included. In addition, electrons gain and lose energy and momentum by absorbing and emitting synchrotron and bremsstrahlung radiation, and through Compton scattering. All evolution equations are handled within a fully covariant framework in the relativistic fixed-metric spacetime of the black hole. Numerical results are presented for five models of low luminosity black hole accretion. In the case of a model with a mass accretion rateṀ ∼ 4 × 10 −8ṀEdd , we find that radiation has a negligible effect on either the dynamics or the thermodynamics of the accreting gas. In contrast, a model with a largerṀ ∼ 4 × 10 −4ṀEdd behaves very differently. The accreting gas is much cooler and the flow is geometrically less thick, though it is not quite a thin accretion disk.

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“…For κ es , we use the following energy and angle averaged Klein-Nishina formula (Buchler & Yueh 1976;Paczyński 1983), for consistency,…”

Section: Scattering and Comptonizationmentioning

confidence: 99%

Radiative, two-temperature simulations of low-luminosity black hole accretion flows in general relativity

Sądowski

Wielgus

Narayan

et al. 2016

Mon. Not. R. Astron. Soc.

128

156

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“…The equation of state and other thermodynamic quantities are computed using the default mesa option, which is based on a blend of the tables of Rogers & Nayfonov (2002, OPAL), Saumon, Chabrier & van Horn (1995, SCVH), Timmes & Swesty (2000, HELM) and Potekhin & Chabrier (2010, PC). The radiative opacity is that of the OPAL collaboration (Iglesias & Rogers 1996), including the effect of molecules, supplemented by the work of Ferguson et al (2005) for low temperatures and of Buchler & Yueh (1976) for pure electron-scattering at high temperatures. We use the OPAL Type 2 opacity tables which allow for varying carbon and oxygen abundance.…”

Section: Mesa/star Stellar Evolution Codementioning

confidence: 99%

Hydrogen in hot subdwarfs formed by double helium white dwarf mergers

Hall

Jeffery

2016

Mon. Not. R. Astron. Soc.

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Isolated hot subdwarfs might be formed by the merging of two helium-core white dwarfs. Before merging, helium-core white dwarfs have hydrogen-rich envelopes and some of this hydrogen may survive the merger. We calculate the mass of hydrogen that is present at the start of such mergers and, with the assumption that hydrogen is mixed throughout the disrupted white dwarf in the merger process, estimate how much can survive. We find a hydrogen mass of up to about 2 × 10 −3 M in merger remnants. We make model merger remnants that include the hydrogen mass appropriate to their total mass and compare their atmospheric parameters with a sample of apparently isolated hot subdwarfs, hydrogen-rich sdBs. The majority of these stars can be explained as the remnants of double helium white dwarf mergers.

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“…To formulate the kinetic equation for the photon distribution function we use a relativistically covariant formalism (Berestetskii et al 1982;Buchler & Yueh 1976). As a reference system, we have chosen the system which is fixed to the cosmic microwave background radiation (CMBR).…”

Section: Lorentz-boosted Kompaneets Equationmentioning

confidence: 99%

“…Stebbins (1997) generalized the Kompaneets equation. Itoh et al (1998) have adopted a relativistically covariant formalism to describe the Compton scattering process (Berestetskii et al 1982;Buchler & Yueh 1976), thereby obtaining higher-order relativistic corrections to the thermal Sunyaev-Zeldovich effect in the form of the Fokker-Planck expansion. In their derivation, the scheme to conserve the photon number at every stage of the expansion proposed by Challinor & Lasenby (1998) played an essential role.…”

Section: Introductionmentioning

confidence: 99%

Relativistic corrections to the Sunyaev-Zeldovich effect for clusters of galaxies: effect of the motion of the observer

Nozawa

Itoh

Kohyama

2005

A&A

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Abstract.We extend the formalism of the relativistic thermal and kinematical Sunyaev-Zeldovich effects to the observer's system (the Solar System) moving with a velocity β S ≡ u S /c with respect to the cosmic microwave background radiation. The present formulation makes full use of the Lorentz covariance properties of the problem and gives solutions with high precision. We confirm the results recently obtained by Chluba, Huetsi, and Sunyaev in the lowest order of the observer's velocity β S . We give a more general analytic expression for the thermal and kinematical Sunyaev-Zeldovich effects corresponding to the observer's system (the Solar System) with the power series expansion approximation in terms of θ e ≡ k B T e /mc 2 , where T e and m are the electron temperature and the electron mass, respectively.

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Compton scattering opacities in a partially degenerate electron plasma at high temperatures

Cited by 171 publications

References 0 publications

Radiative, two-temperature simulations of low-luminosity black hole accretion flows in general relativity

Radiative, two-temperature simulations of low-luminosity black hole accretion flows in general relativity

Hydrogen in hot subdwarfs formed by double helium white dwarf mergers

Relativistic corrections to the Sunyaev-Zeldovich effect for clusters of galaxies: effect of the motion of the observer

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