Viscous Transonic Accretion Flows in Kerr Black Hole Geometry
We study viscous transonic accretion flows in vertical equilibrium in Kerr geometry. We employ the pseudo-Kerr formalism that accurately describes transonic flows around Kerr black holes and is applicable for modeling observational data. We study the effects of viscosity on the nature of sonic point...
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IOP Publishing
2024-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/ad84dd |
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| author | Abhrajit Bhattacharjee Sandip K. Chakrabarti |
| author_facet | Abhrajit Bhattacharjee Sandip K. Chakrabarti |
| author_sort | Abhrajit Bhattacharjee |
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| description | We study viscous transonic accretion flows in vertical equilibrium in Kerr geometry. We employ the pseudo-Kerr formalism that accurately describes transonic flows around Kerr black holes and is applicable for modeling observational data. We study the effects of viscosity on the nature of sonic points and the parameter space that allows an accretion flow to possess multiple sonic points. We concentrate on the accretion solutions that can have centrifugal pressure supported shock waves and find that the shocks are weaker and are located farther from the black hole as the viscosity is enhanced. Moreover, if the viscosity is greater than a critical value, shocks do not form and the accretion flow can pass only through the inner sonic point close to the black hole and remains subsonic and Keplerian throughout the accretion disk. Since the resonance oscillation frequencies of the shock waves provide a measure of the observed quasiperiodic oscillation (QPO) frequencies, and since the location of shock waves depend on the spin of a black hole, it is clear that the QPO frequencies must depend on the spin of black hole as well. Our pseudo-Kerr approach makes it easier to compute spectra from an accretion flow with viscous dissipation and radiative cooling around a spinning black hole. |
| format | Article |
| id | doaj-art-e947f1f354924ca1a41e010c18793ff6 |
| institution | Kabale University |
| issn | 1538-4357 |
| language | English |
| publishDate | 2024-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj-art-e947f1f354924ca1a41e010c18793ff62024-12-02T11:48:47ZengIOP PublishingThe Astrophysical Journal1538-43572024-01-0197715410.3847/1538-4357/ad84ddViscous Transonic Accretion Flows in Kerr Black Hole GeometryAbhrajit Bhattacharjee0https://orcid.org/0000-0003-3886-4763Sandip K. Chakrabarti1https://orcid.org/0000-0002-0193-1136Indian Centre for Space Physics , 466, Barakhola, Netai Nagar, Kolkata 700099, IndiaIndian Centre for Space Physics , 466, Barakhola, Netai Nagar, Kolkata 700099, IndiaWe study viscous transonic accretion flows in vertical equilibrium in Kerr geometry. We employ the pseudo-Kerr formalism that accurately describes transonic flows around Kerr black holes and is applicable for modeling observational data. We study the effects of viscosity on the nature of sonic points and the parameter space that allows an accretion flow to possess multiple sonic points. We concentrate on the accretion solutions that can have centrifugal pressure supported shock waves and find that the shocks are weaker and are located farther from the black hole as the viscosity is enhanced. Moreover, if the viscosity is greater than a critical value, shocks do not form and the accretion flow can pass only through the inner sonic point close to the black hole and remains subsonic and Keplerian throughout the accretion disk. Since the resonance oscillation frequencies of the shock waves provide a measure of the observed quasiperiodic oscillation (QPO) frequencies, and since the location of shock waves depend on the spin of a black hole, it is clear that the QPO frequencies must depend on the spin of black hole as well. Our pseudo-Kerr approach makes it easier to compute spectra from an accretion flow with viscous dissipation and radiative cooling around a spinning black hole.https://doi.org/10.3847/1538-4357/ad84ddBlack hole physicsGravitationRelativityAccretion |
| spellingShingle | Abhrajit Bhattacharjee Sandip K. Chakrabarti Viscous Transonic Accretion Flows in Kerr Black Hole Geometry The Astrophysical Journal Black hole physics Gravitation Relativity Accretion |
| title | Viscous Transonic Accretion Flows in Kerr Black Hole Geometry |
| title_full | Viscous Transonic Accretion Flows in Kerr Black Hole Geometry |
| title_fullStr | Viscous Transonic Accretion Flows in Kerr Black Hole Geometry |
| title_full_unstemmed | Viscous Transonic Accretion Flows in Kerr Black Hole Geometry |
| title_short | Viscous Transonic Accretion Flows in Kerr Black Hole Geometry |
| title_sort | viscous transonic accretion flows in kerr black hole geometry |
| topic | Black hole physics Gravitation Relativity Accretion |
| url | https://doi.org/10.3847/1538-4357/ad84dd |
| work_keys_str_mv | AT abhrajitbhattacharjee viscoustransonicaccretionflowsinkerrblackholegeometry AT sandipkchakrabarti viscoustransonicaccretionflowsinkerrblackholegeometry |