X-Ray Spectra from General Relativistic Radiation Magnetohydrodynamic Simulations of Thin Disks
We compare X-ray emission from several general relativistic, multifrequency, radiation magnetohydrodynamic simulations of thin black hole accretion disks with different accretion rates and spins. The simulations were performed using the M _1 closure scheme, resolved with 12 frequency (energy) bins l...
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IOP Publishing
2025-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/adb1c1 |
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| author | Nathaniel Roth Peter Anninos P. Chris Fragile Derrick Pickrel |
| author_facet | Nathaniel Roth Peter Anninos P. Chris Fragile Derrick Pickrel |
| author_sort | Nathaniel Roth |
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| description | We compare X-ray emission from several general relativistic, multifrequency, radiation magnetohydrodynamic simulations of thin black hole accretion disks with different accretion rates and spins. The simulations were performed using the M _1 closure scheme, resolved with 12 frequency (energy) bins logarithmically spaced from 5 × 10 ^−3 to 5 × 10 ^3 keV. We apply a general relativistic Monte Carlo transport code to postprocess the simulation data with greater fidelity in frequency resolution and Compton scattering treatment. Despite the relatively few energy bins and Kompaneets approximation to Compton scattering utilized in the M _1 method, we find generally good agreement between the methods. Both produce prominent thermal profiles with peaks around 2–2.5 keV, where agreement is particularly strong and representative of the soft state. Both also find weaker (lower-luminosity) thermally sourced emission extending out to 100 keV due to the hotter innermost regions of the disks. Inverse Compton scattering becomes increasingly effective at hardening spectral outputs with increasing black hole spin, and becomes the dominant mechanism for photons that escape with energies between 10 to several hundred keV. At very high rates of spin, the radiation flux in this upscattered component becomes comparable to the thermal flux, a phenomenon typically associated with intermediate states. Beyond 10 ^4 keV, we observe faint, free–free emission from hot, optically thin coronal regions developing near the horizon, common to both spinning and nonspinning black holes. |
| format | Article |
| id | doaj-art-073911e95c7d4e729363d41ac5ecdaee |
| institution | Kabale University |
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| publishDate | 2025-01-01 |
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| spelling | doaj-art-073911e95c7d4e729363d41ac5ecdaee2025-08-20T04:03:21ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-01981214410.3847/1538-4357/adb1c1X-Ray Spectra from General Relativistic Radiation Magnetohydrodynamic Simulations of Thin DisksNathaniel Roth0https://orcid.org/0000-0002-6485-2259Peter Anninos1P. Chris Fragile2https://orcid.org/0000-0002-5786-186XDerrick Pickrel3Lawrence Livermore National Laboratory , P.O. Box 808, Livermore, CA 94550, USALawrence Livermore National Laboratory , P.O. Box 808, Livermore, CA 94550, USADepartment of Physics and Astronomy, College of Charleston , 66 George Street, Charleston, SC 29424, USADepartment of Physics, University of California , 5200 North Lake Road, Merced, CA 95343, USAWe compare X-ray emission from several general relativistic, multifrequency, radiation magnetohydrodynamic simulations of thin black hole accretion disks with different accretion rates and spins. The simulations were performed using the M _1 closure scheme, resolved with 12 frequency (energy) bins logarithmically spaced from 5 × 10 ^−3 to 5 × 10 ^3 keV. We apply a general relativistic Monte Carlo transport code to postprocess the simulation data with greater fidelity in frequency resolution and Compton scattering treatment. Despite the relatively few energy bins and Kompaneets approximation to Compton scattering utilized in the M _1 method, we find generally good agreement between the methods. Both produce prominent thermal profiles with peaks around 2–2.5 keV, where agreement is particularly strong and representative of the soft state. Both also find weaker (lower-luminosity) thermally sourced emission extending out to 100 keV due to the hotter innermost regions of the disks. Inverse Compton scattering becomes increasingly effective at hardening spectral outputs with increasing black hole spin, and becomes the dominant mechanism for photons that escape with energies between 10 to several hundred keV. At very high rates of spin, the radiation flux in this upscattered component becomes comparable to the thermal flux, a phenomenon typically associated with intermediate states. Beyond 10 ^4 keV, we observe faint, free–free emission from hot, optically thin coronal regions developing near the horizon, common to both spinning and nonspinning black holes.https://doi.org/10.3847/1538-4357/adb1c1AccretionRadiative magnetohydrodynamicsAstrophysical fluid dynamicsRadiative transferRelativistic disksRotating black holes |
| spellingShingle | Nathaniel Roth Peter Anninos P. Chris Fragile Derrick Pickrel X-Ray Spectra from General Relativistic Radiation Magnetohydrodynamic Simulations of Thin Disks The Astrophysical Journal Accretion Radiative magnetohydrodynamics Astrophysical fluid dynamics Radiative transfer Relativistic disks Rotating black holes |
| title | X-Ray Spectra from General Relativistic Radiation Magnetohydrodynamic Simulations of Thin Disks |
| title_full | X-Ray Spectra from General Relativistic Radiation Magnetohydrodynamic Simulations of Thin Disks |
| title_fullStr | X-Ray Spectra from General Relativistic Radiation Magnetohydrodynamic Simulations of Thin Disks |
| title_full_unstemmed | X-Ray Spectra from General Relativistic Radiation Magnetohydrodynamic Simulations of Thin Disks |
| title_short | X-Ray Spectra from General Relativistic Radiation Magnetohydrodynamic Simulations of Thin Disks |
| title_sort | x ray spectra from general relativistic radiation magnetohydrodynamic simulations of thin disks |
| topic | Accretion Radiative magnetohydrodynamics Astrophysical fluid dynamics Radiative transfer Relativistic disks Rotating black holes |
| url | https://doi.org/10.3847/1538-4357/adb1c1 |
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