Periodic mass loss from viscous accretion flows around black holes

Mon. Not. R. Astron. Soc.

2016

Self Cite

We investigated flow in Schwarzschild metric, around a non-rotating black hole and obtained self-consistent accretion -ejection solution in full general relativity. We covered the whole of parameter space in the advective regime to obtain shocked, as well as, shock-free accretion solution. We computed the jet streamline using von -Zeipel surfaces and projected the jet equations of motion on to the streamline and solved them simultaneously with the accretion disc equations of motion. We found that steady shock cannot exist for α > ∼ 0.06 in the general relativistic prescription, but is lower if mass -loss is considered too. We showed that for fixed outer boundary, the shock moves closer to the horizon with increasing viscosity parameter. The mass outflow rate increases as the shock moves closer to the black hole, but eventually decreases, maximizing at some intermediate value of shock location. The jet terminal speed increases with stronger shocks, quantitatively speaking, the terminal speed of jets v j∞ > 0.1 if r sh < 20r g . The maximum of the outflow rate obtained in the general relativistic regime is less than 6% of the mass accretion rate.

Section: Introductionmentioning

confidence: 57%

Section: To Find Jet Critical Point and Mass Outflow Ratementioning

confidence: 99%

Estimation of mass outflow rates from viscous relativistic accretion discs around black holes

Chattopadhyay

Mon. Not. R. Astron. Soc.

2016

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“…It has been shown earlier that VZS are the surfaces of constant angular momentum and also of constant entropy for fluid flow above the equatorial plane (Chakrabarti 1985). In addition, numerical simulations showed that the entire PSD generates bipolar jets (Molteni et al 1996b;Lanzafame et al 1998;Das et al 2014;Lee et al 2016). So, we choose the foot point (r b ) of the jet streamline located half way between the accretion shock and inner critical point of the disc, but on the surface of PSD.…”

Section: Discussion and Summarymentioning

confidence: 99%

Estimation of bipolar jets from accretion discs around Kerr black holes

Monthly Notices of the Royal Astronomical Society

Chattopadhyay

2017

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We analyse flows around a rotating black hole and obtain self-consistent accretionejection solutions in full general relativistic prescription. Entire energy-angular momentum parameter space is investigated in the advective regime to obtain shocked and shock-free accretion solutions. Jet equations of motion are solved along the von-Zeipel surfaces computed from the post-shock disc, simultaneously with the equations of accretion disc along the equatorial plane. For a given spin parameter, the mass outflow rate increases as the shock moves closer to the black hole, but eventually decreases, maximizing at some intermediate value of shock location. Interestingly, we obtain all types of possible jet solutions, for example, steady shock solution with multiple critical points, bound solution with two critical points and smooth solution with single critical point. Multiple critical points may exist in jet solution for spin parameter a s 0.5. The jet terminal speed generally increases if the accretion shock forms closer to the horizon and is higher for corotating black hole than the counter-rotating and the non-rotating one. Quantitatively speaking, shocks in jet may form for spin parameter a s > 0.6 and jet shocks range between 6r g and 130r g above the equatorial plane, while the jet terminal speed v j∞ > 0.35c if Bernoulli parameter E 1.01 for a s > 0.99.

“…This assumption has been dictated by a large number of simulations, which showed SKD to have a flatter surface compared to PSD (Molteni et al 1994(Molteni et al , 1996Giri & Chakrabarti 2013;Das et. al.…”

Section: Accretion Disc and Radiative Momentsmentioning

confidence: 99%

“…Generally most of the papers which investigate the interaction of jet with disc photons do not consider the issue of the launch mechanism of jets in terms of the accretion properties. In the advective disc regime, numerical simulations first showed that the extrathermal gradient force in the PSD automatically generates bipolar outflows (Molteni et al 1994(Molteni et al , 1996Das et. al.…”

Section: Introductionmentioning

confidence: 99%

Radiatively driven relativistic jets with variable adiabatic index equation of state

Vyas

Mon. Not. R. Astron. Soc.

Mandal

et al. 2015

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We investigate a relativistic fluid jet driven by radiation from a shocked accretion disc around a non-rotating black hole approximated by Paczyński-Wiita potential. The sub-Keplerian and Keplerian accretion rates control the shock location and therefore, the radiation field around the accretion disc. We compute the radiative moments with full special relativistic transformation. The effect of a fraction of radiation absorbed by the black hole has been approximated, over and above the special relativistic transformations. We show that the radiative moments around a super massive black hole are different compared to that around a stellar mass black hole. We show that the terminal speed of jets increases with the mass accretion rates,synchrotron emission of the accretion disc and reduction of proton fraction of the flow composition. To obtain relativistic terminal velocities of jets, both thermal and radiative driving are important. We show for very high accretion rates and pair dominated flow, jets around super massive black holes are truly ultra-relativistic, while for jets around stellar mass black holes, terminal Lorentz factor of about 10 is achievable.