Imprints of Different Types of Low-angular-momentum Accretion Flow Solutions in General Relativistic Hydrodynamic Simulations
Depending on the astrophysical source and its environment, the accretion flows can exhibit a variety of behaviors and characteristics in accordance with the type of solutions. We study low-angular-momentum accretion flows onto black holes using 2D general relativistic hydrodynamic simulations to fin...
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2025-01-01
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| Online Access: | https://doi.org/10.3847/1538-4357/adf221 |
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| author | Indu K. Dihingia Akhil Uniyal Yosuke Mizuno |
| author_facet | Indu K. Dihingia Akhil Uniyal Yosuke Mizuno |
| author_sort | Indu K. Dihingia |
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| description | Depending on the astrophysical source and its environment, the accretion flows can exhibit a variety of behaviors and characteristics in accordance with the type of solutions. We study low-angular-momentum accretion flows onto black holes using 2D general relativistic hydrodynamic simulations to find imprints of different types of accretion solutions. Such flows, relevant to X-ray binaries and wind-fed low-luminosity active galactic nuclei, often lack sufficient angular momentum to form standard accretion disks. We initialize simulations with semianalytical transonic solutions defined by specific energy ( ${{ \mathcal E }}_{0}$ ) and angular momentum ( λ _0 ), allowing a systematic classification of flow types with: (i) an outer sonic point, (ii) an inner sonic point, and (iii) both, exhibiting shock transitions. Only solutions with two sonic points produce hot, thermally driven bipolar jets/outflows with Lorentz factors up to γ ∼ 2, despite the absence of magnetic fields. Using a general relativistic radiation transfer calculation, we compute broadband spectra and images at X-ray (1 keV) from bremsstrahlung emission. Radiative properties depend strongly on the type of accretion solution. Solutions with inner sonic points produce the brightest and most extended X-ray emission, while outer-point solutions produce compact, fainter signals. These multidimensional models are thus essential for predicting radiative signatures and will enable the development of semianalytical tools for interpreting X-ray binaries and possibly Sgr A* in weak magnetic field regimes. |
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| institution | Kabale University |
| issn | 1538-4357 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
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| series | The Astrophysical Journal |
| spelling | doaj-art-e65e08b79b594f8487d4ecbcb62edc742025-08-22T06:19:35ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-0199013510.3847/1538-4357/adf221Imprints of Different Types of Low-angular-momentum Accretion Flow Solutions in General Relativistic Hydrodynamic SimulationsIndu K. Dihingia0https://orcid.org/0000-0002-4064-0446Akhil Uniyal1https://orcid.org/0000-0001-8213-646XYosuke Mizuno2https://orcid.org/0000-0002-8131-6730Tsung-Dao Lee Institute, Shanghai Jiao Tong University , 1 Lisuo Road, Shanghai, 201210, People’s Republic of China ; ikd4638@gmail.com, ikd4638@sjtu.edu.cn, mizuno@sjtu.edu.cnTsung-Dao Lee Institute, Shanghai Jiao Tong University , 1 Lisuo Road, Shanghai, 201210, People’s Republic of China ; ikd4638@gmail.com, ikd4638@sjtu.edu.cn, mizuno@sjtu.edu.cnTsung-Dao Lee Institute, Shanghai Jiao Tong University , 1 Lisuo Road, Shanghai, 201210, People’s Republic of China ; ikd4638@gmail.com, ikd4638@sjtu.edu.cn, mizuno@sjtu.edu.cn; School of Physics and Astronomy, Shanghai Jiao Tong University , 800 Dongchuan Road, Shanghai, 200240, People’s Republic of China; Key Laboratory for Particle Physics, Astrophysics and Cosmology (MOE), Shanghai Key Laboratory for Particle Physics and Cosmology, Shanghai Jiao-Tong University , 800 Dongchuan Road, Shanghai, 200240, People’s Republic of China; Institut für Theoretische Physik, Goethe-Universität Frankfurt , Max-von-Laue-Strasse 1, D-60438 Frankfurt am Main, GermanyDepending on the astrophysical source and its environment, the accretion flows can exhibit a variety of behaviors and characteristics in accordance with the type of solutions. We study low-angular-momentum accretion flows onto black holes using 2D general relativistic hydrodynamic simulations to find imprints of different types of accretion solutions. Such flows, relevant to X-ray binaries and wind-fed low-luminosity active galactic nuclei, often lack sufficient angular momentum to form standard accretion disks. We initialize simulations with semianalytical transonic solutions defined by specific energy ( ${{ \mathcal E }}_{0}$ ) and angular momentum ( λ _0 ), allowing a systematic classification of flow types with: (i) an outer sonic point, (ii) an inner sonic point, and (iii) both, exhibiting shock transitions. Only solutions with two sonic points produce hot, thermally driven bipolar jets/outflows with Lorentz factors up to γ ∼ 2, despite the absence of magnetic fields. Using a general relativistic radiation transfer calculation, we compute broadband spectra and images at X-ray (1 keV) from bremsstrahlung emission. Radiative properties depend strongly on the type of accretion solution. Solutions with inner sonic points produce the brightest and most extended X-ray emission, while outer-point solutions produce compact, fainter signals. These multidimensional models are thus essential for predicting radiative signatures and will enable the development of semianalytical tools for interpreting X-ray binaries and possibly Sgr A* in weak magnetic field regimes.https://doi.org/10.3847/1538-4357/adf221AccretionBlack hole physicsHigh energy astrophysicsX-ray binary stars |
| spellingShingle | Indu K. Dihingia Akhil Uniyal Yosuke Mizuno Imprints of Different Types of Low-angular-momentum Accretion Flow Solutions in General Relativistic Hydrodynamic Simulations The Astrophysical Journal Accretion Black hole physics High energy astrophysics X-ray binary stars |
| title | Imprints of Different Types of Low-angular-momentum Accretion Flow Solutions in General Relativistic Hydrodynamic Simulations |
| title_full | Imprints of Different Types of Low-angular-momentum Accretion Flow Solutions in General Relativistic Hydrodynamic Simulations |
| title_fullStr | Imprints of Different Types of Low-angular-momentum Accretion Flow Solutions in General Relativistic Hydrodynamic Simulations |
| title_full_unstemmed | Imprints of Different Types of Low-angular-momentum Accretion Flow Solutions in General Relativistic Hydrodynamic Simulations |
| title_short | Imprints of Different Types of Low-angular-momentum Accretion Flow Solutions in General Relativistic Hydrodynamic Simulations |
| title_sort | imprints of different types of low angular momentum accretion flow solutions in general relativistic hydrodynamic simulations |
| topic | Accretion Black hole physics High energy astrophysics X-ray binary stars |
| url | https://doi.org/10.3847/1538-4357/adf221 |
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