Relativistic simulation of flip-flop instabilities of Bondi-Hoyle accretion and quasi-periodic oscillations

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dc.contributor.authorDonmez, O.
dc.date.accessioned2019-08-01T13:38:39Z
dc.date.available2019-08-01T13:38:39Z
dc.date.issued2012
dc.departmentNiğde ÖHÜ
dc.description.abstractIt is known from recent numerical calculations that BondiHoyle accretion creates a shock cone behind compact objects. This type of accretion leads to instabilities, which can explain certain astrophysical phenomena. In this paper, our main goal is to find the flip-flop behaviour of the shock cone in the relativistic region. In order to do so we have modelled the dynamics of a shock cone around non-rotating and rotating black holes at the equatorial plane in 2D. The effects of the various parameters on the shock cones and instabilities, such as the asymptotic velocity, sound speed, Mach number and adiabatic index, are studied. We have determined the mass accretion rate, shock opening angle, shock cone oscillation, quasi-periodic oscillations (QPOs), and growth rate of instabilities to reveal the disc properties and its radiation. We have discovered, for the first time, flip-flop instabilities around a black hole in the relativistic region by solving the general relativistic hydrodynamical equations. The flip-flop instabilities are found for sound speeds Cs, 8 < 0.2 with moderate Mach numbers ( M=3 and M=4 for Cs, 8 = 0.1 or M=7 and M=8 for Cs, 8 = 0.05). Our calculation clearly confirms that the shock cone should be detached from the black hole in the BondiHoyle accretion flow with G = 2 for non-rotating and rotating black holes. Results reveal that the flip-flopping shock cone not only creates a torque effect on the black hole but also produces continuous X-ray flares with a certain frequency. Furthermore, QPOs originate inside the shock cone and are stronger in regions that have a radius of a few gravitational radii away from the centre owing to the flip-flop oscillation. Finally, our results are compared with the results of numerical and theoretical calculations in Newtonian hydrodynamics, and it is found that they are in good agreement.
dc.description.sponsorshipNational Center for High Performance Computing of Turkey (UYBHM) [10022007]; TUBITAK ULAKBIM, High-Performance and Grid-Computing Center (TR-Grid e-Infrastructure); COST Action [MP0905]; TUBITAK [109T519]
dc.description.sponsorshipWe thank the anonymous referee for constructive comments, which led to improvements in the manuscript. The numerical calculations were performed at the National Center for High Performance Computing of Turkey (UYBHM) under grant number 10022007, and TUBITAK ULAKBIM, High-Performance and Grid-Computing Center (TR-Grid e-Infrastructure). Part of this work was supported by the COST Action MP0905 Black Holes in a Violent Universe and TUBITAK short-term RBD Funding Programme with project number 109T519.
dc.identifier.doi10.1111/j.1365-2966.2012.21616.x
dc.identifier.endpage1545
dc.identifier.issn0035-8711
dc.identifier.issue2
dc.identifier.scopus2-s2.0-84867085900
dc.identifier.scopusqualityQ1
dc.identifier.startpage1533
dc.identifier.urihttps://dx.doi.org/10.1111/j.1365-2966.2012.21616.x
dc.identifier.urihttps://hdl.handle.net/11480/4535
dc.identifier.volume426
dc.identifier.wosWOS:000309456200057
dc.identifier.wosqualityQ1
dc.indekslendigikaynakWeb of Science
dc.indekslendigikaynakScopus
dc.institutionauthorDonmez, O.
dc.language.isoen
dc.publisherOXFORD UNIV PRESS
dc.relation.ispartofMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
dc.relation.publicationcategoryMakale - Uluslararası Hakemli Dergi - Kurum Öğretim Elemanı
dc.rightsinfo:eu-repo/semantics/openAccess
dc.subjectaccretion
dc.subjectaccretion discs
dc.subjectblack hole physics
dc.subjectinstabilities
dc.subjectrelativistic processes
dc.titleRelativistic simulation of flip-flop instabilities of Bondi-Hoyle accretion and quasi-periodic oscillations
dc.typeArticle

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