Properties of magnetically supported dissipative accretion flow around black holes with cooling effects

Sarkar, Biplob; Das, Santabrata; Mandal, Samir

doi:10.1093/mnras/stx2505

Cited by 20 publications

(13 citation statements)

References 59 publications

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“…For two jets, and with some of the accretion not ending up in the jets, our value is consistent with theirs. The value of α falls in the range α = 0.23 ± 0.1 estimated by Coroniti (1981) in a magnetic flux cell model (quoted in Sakimoto and Coroniti (1981)), and agrees with α ∼ 0.27 from steady state models by Sarkar et al (2018). Even though in different scales, also for dwarf nova and X-ray transient outbursts one finds α = 0.25 ± 0.15 (King et al 2007).…”

Section: Disk Model and Parameterssupporting

confidence: 83%

Accretion Disk Parameters Determined from the Great 2015 Flare of OJ 287

Valtonen

Zoła

Pihajoki

et al. 2019

ApJ

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In the binary black hole model of OJ 287 the secondary black hole orbits a much more massive primary, and impacts on the primary accretion disk at predictable times. We update the parameters of the disk, the viscosity α and the mass accretion rateṁ. We find α = 0.26 ± 0.1 andṁ = 0.08 ± 0.04 in Eddington units. The former value is consistent with Coroniti (1981) and the latter with Marscher and Jorstad (2011). Predictions are made for the 2019 July 30 superflare in OJ 287. We expect that it will take place simultaneously at the Spitzer infrared channels as well as in the optical and that therefore the timing of the flare in optical can be accurately determined from Spitzer observations. We also discuss in detail the light curve of the 2015 flare, and find that the radiating volume has regions where bremsstrahlung dominates as well as regions that radiate primarily in synchrotron radiation. The former region produces the unpolarised first flare while the latter region gives rise to a highly polarized second flare.

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Section: Disk Model and Parameterssupporting

confidence: 83%

Accretion Disk Parameters Determined from the Great 2015 Flare of OJ 287

Valtonen

Zoła

Pihajoki

et al. 2019

ApJ

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“…Furthermore, the existence of toroidal magnetic field has been observationally confirmed in the exterior regions of the discs of young stellar objects as well as in the Galactic center (Chuss et al 2003;Novak et al 2003). Meanwhile, significant efforts were given to examine the accretion disc properties around black holes including toroidal magnetic fields (Akizuki & Fukue 2006;Khesali & Faghei 2008Mosallanezhad, Abbassi, & Beiranvand 2014;Mosallanezhad, Bu, & Yuan 2016;Oda et al 2007Oda et al , 2010Oda et al , 2012Samadi, Abbassi, & Khajavi 2014;Sarkar & Das 2015Sarkar, Das, & Mandal 2018;. Following the above cognizance, in the present work, we consider the accretion flow to be threaded by toroidal magnetic field lines as well.…”

Section: Introductionmentioning

confidence: 96%

“…It may be noted that the global accretion solutions including shock waves are potentially favored as it owns large amount of entropy (Becker & Kazanas 2001). In the theoretical front, the shock induced global accretion solution around black hole and its implications are extensively studied by the numerous groups of workers (Fukue 1987;Chakrabarti 1989Chakrabarti , 1996bLu, Gu, & Yuan 1999;Gu & Lu 2001;Das et al 2001b;Gu & Lu 2004;Fukumura & Tsuruta 2004;Chakrabarti & Das 2004;Das 2007;Becker, Das, & Le 2008;Das, Becker, & Le 2009;Das, Chakrabarti, & Mondal 2010;Sarkar & Das 2015;Aktar, Das, & Nandi 2015;Sarkar & Das 2016;Aktar et al 2017;Sarkar, Das, & Mandal 2018). In addition, the existence of shock in accretion flow is also examined numerically considering hydrodynamics (Chakrabarti & Molteni 1993;Molteni, Lanzafame, & Chakrabarti 1994;Ryu, Chakrabarti, & Molteni 1997;Okuda 2014;Okuda & Das 2015;Suková & Janiuk 2015;Suková, Charzyński, & Janiuk 2017) as well as magnetohydrodynamic (MHD) environment (Nishikawa et al 2005;Takahashi et al 2006;Fukumura, Takahashi, & Tsuruta 2007;Fukumura et al 2016).…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, recalling the success of the seminal α-viscosity prescription (Shakura & Sunyaev 1973), we consider the Maxwell stress to be proportional to the total pressure (Machida, Nakamura, & Matsumoto 2006) that evidently demonstrates that the outward transport of angular momentum would certainly be enhanced as the magnetic activity inside the disc is increased. Furthermore, we consider the heating of the flow to be regulated by the magnetic energy dissipation mechanism while the inflowing matter is being cooled via synchrotron emission process (Chattopadhyay & Chakrabarti 2000;Das 2007;Sarkar, Das, & Mandal 2018). In addition, for simplicity, we adopt a pseudo potential introduced by that successfully mimics the space-time geometry around the rotating black hole having spin a k 0.8.…”

Section: Introductionmentioning

confidence: 99%

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Standing shocks in magnetized advection accretion flows onto a rotating black hole

Das

Sarkar

2018

Monthly Notices of the Royal Astronomical Society

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We present the global structure of magnetized advective accretion flow around the rotating black holes in presence of dissipation. By considering accretion flow to be threaded by toroidal magnetic fields and by assuming synchrotron radiative mechanism to be the dominant cooling process, we obtain global transonic accretion solutions in terms of dissipation parameters, such as viscosity (α B ), accretion rate (ṁ) and plasma-β, respectively. In the rotating magnetized accretion flow, centrifugal barrier is developed in the nearby region of the black hole that triggers the discontinuous shock transition in the flow variables. Evidently, the shock properties and the dynamics of the post-shock flow (hereafter post-shock corona (PSC)) are being governed by the flow parameters. We study the role of dissipation parameters in the formation of standing shock wave and find that global shocked accretion solutions exist both in gas pressure dominated flows and in magnetic pressure dominated flows. In addition, we observe that standing shock continues to form around the rapidly rotating black holes as well. We identify the range of dissipation parameters that permits shocked accretion solutions and find that standing shocks continue to form even in presence of high dissipation limit, although the likelihood of shock formation diminishes with the increase of dissipation. Further, we compute the critical accretion rate (ṁ cri ) that admits shock and observe that standing shock exists in a magnetically dominated accretion flow when the accretion rate lies in general in the sub-Eddington domain. At the end, we calculate the maximum dissipated energy that may be escaped from the PSC and indicate its possible implication in the astrophysical context.

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“…Since, black hole does not have any hard boundary, post-shock flow acts as a effective boundary layer around the black hole which is commonly called as post-shock corona (PSC) (Aktar et al 2015). Note that the existence of shock wave in an accretion flow and their astrophysical implications have been extensively studied in the literature both analytically and numerically (Fukue 1987;Chakrabarti 1989;Lu et al 1999;Becker & Kazanas 2001;Das et al 2001;Fukumura & Tsuruta 2004;Chattopadhyay & Das 2007;Das & Chattopadhyay 2008;Das et al 2014;Suková & Janiuk 2015;Le et al 2016;Aktar et al 2017;Sarkar et al 2018;Dihingia et al 2018).…”

Section: Introductionmentioning

confidence: 99%

Accretion-ejection in rotating black holes: a model for ‘outliers’ track of radio-X-ray correlation in X-ray binaries

Aktar

Nandi

Das

2019

Astrophys Space Sci

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We study the global accretion-ejection solutions around a rotating black hole considering three widely accepted pseudo-Kerr potentials that satisfactorily mimic the space-time geometry of rotating black holes. We find that all the pseudo potentials provide standing shock solutions for large range of flow parameters. We identify the effective region of the shock parameter space spanned by energy (E in ) and angular momentum (λ in ) measured at the inner critical point (x in ) and find that the possibility of shock formation becomes feeble when the viscosity parameter (α) is increased. In addition, we find that shock parameter space also depends on the adiabatic index (γ) of the flow and the shock formation continues to take place for a wide range of γ as 1.5 ≤ γ ≤ 4/3. For all the pseudo potentials, we calculate the critical viscosity parameter (α cri shock ) beyond which standing shock ceases to exist and compare them as function of black hole spin (a k ). We observe that all the pseudo potentials under consideration are qualitatively similar as far as the standing shocks are concerned, however, they differ both qualitatively and quantitatively from each other for rapidly rotating black holes. Further, we compute the mass loss from the disc using all three pseudo potentials and find that the maximum mass outflow rate (R maẋ m ) weakly depends on the black hole spin. To validate our model, we calculate the maximum jet kinetic power using the accretion-ejection formalism and compare it with the radio jet power of low-hard state of the black hole X-ray binaries (hereafter XRBs). The outcome of our results indicate that XRBs along the 'outliers' track might be rapidly rotating.

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Properties of magnetically supported dissipative accretion flow around black holes with cooling effects

Cited by 20 publications

References 59 publications

Accretion Disk Parameters Determined from the Great 2015 Flare of OJ 287

Accretion Disk Parameters Determined from the Great 2015 Flare of OJ 287

Standing shocks in magnetized advection accretion flows onto a rotating black hole

Accretion-ejection in rotating black holes: a model for ‘outliers’ track of radio-X-ray correlation in X-ray binaries

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