Effects of Fluid Composition on Spherical Flows Around Black Holes

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.

show abstract

“…where, ρ(= ρeτ = nemeτ ) is the total mass density (see details in Chattopadhyay 2008;Chattopadhyay & Ryu 2009),…”

Section: The Fluid Its Eos and The Background Metricmentioning

confidence: 99%

Estimation of bipolar jets from accretion discs around Kerr black holes

Kumar

Chattopadhyay

2017

Monthly Notices of the Royal Astronomical Society

Self Cite

View full text Add to dashboard Cite

show abstract

“…Additionally, being algebraic and avoiding the presence of complicated special functions, this EoS is very easy to be implemented in simulation codes, as well as, be used in analytical investigations (Chattopadhyay & Ryu 2009;Chattopadhyay & Chakrabarti 2011;Ryu et al 2006;Chattopadhyay et al 2013). The jet plasma is fully ionized.…”

Section: Equation Of State and The Final Form Of Equations Of Motionmentioning

confidence: 99%

“…Taub (1948) showed that it is unphysical to consider a fixed Γ to describe fluid with several orders of magnitude variation in temperature. Moreover, it has also been shown that, not only temperature, relativistic nature of the thermal energy depends also on the composition of the flow (Chattopadhyay 2008;Chattopadhyay & Ryu 2009;Chattopadhyay & Chakrabarti 2011;Chattopadhyay et al 2013;. Infact it was shown that, contrary to expectation, pairplasma is thermally the least relativistic, and to make a flow more relativistic one needs baryons in addition to electrons or positrons, and the fluid with proton number density around 27% of that of electrons is thermally the most relativistic.…”

Section: Introductionmentioning

confidence: 99%

Radiatively driven relativistic jets with variable adiabatic index equation of state

Vyas

Kumar

Mandal

et al. 2015

Mon. Not. R. Astron. Soc.

Self Cite

View full text Add to dashboard Cite

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.

show abstract

“…Consider the timelike Killing vector ξ µ t of the metric (1), Eq. (18) yields ∂ r (hu t ) = 0 (where we have used (11) and u θ = 0 on the θ = π/2 plane).…”

Section: General Equations For Accretion Of Rotating Fluidsmentioning

confidence: 99%

“…Full analytical treatments [4][5][6][7][8] drop back reaction effects for simplicity and cognitive treatments [9][10][11][12][13][14][15] may include emission effects and neglect back reaction too.…”

mentioning

confidence: 99%

Accretion of rotating fluids onto stationary solutions

Azreg‐Aïnou

2017

Phys. Rev. D

View full text Add to dashboard Cite

We consider a general stationary solution and derive the general laws for accretion of rotating perfect fluids. For non-degenerate and degenerate Fermi and Bose fluids we derive new effects that mimic the center-of-mass-energy effect of two colliding particle in the vicinity of horizons. Nondegenerate fluids see their chemical potential grow arbitrarily and ultra-relativistic Fermi fluids see their specific enthalpy and Fermi momentum grow arbitrarily too while the latter vanishes gradually for non-relativistic Fermi fluids. For degenerate Bose fluids two scenarios remain possible as the fluid approaches a horizon: a) The Bose-Einstein condensation ceases or b) the temperature drops gradually down to zero. The critical flow is also investigated. I. WHAT IS ACCRETION?Given a metric solution of spacetime, a geodesic motion is the process by which a massive or massless test particle "falls" freely. The fall motion may be bounded (circular motion or else) or unbounded (scattering motion). The free fall of the test particle does not disturb, affect, or modify the given geometry: No back reaction effects are taken into consideration. Moreover, no group motion is treated in geodesic motion. Back reaction effects are present in the calculation of gravitational self forces where the motion of the "small" body is still seen as geodesic in the perturbed metric.Accretion is an advanced state of motion. It describes group motion with and without back reaction and it is generally non-geodesic. By group motion it is meant that the accreting matter is modeled by a fluid and that each fluid element encompasses a) a sufficiently large number of particles to be described statistically by an average pressure, average temperature, average particle number density, and average energy density; b) a sufficiently small number of particles compared to the whole system (accreting matter, atmosphere, etc). These conditions are easily met in astrophysics and atmospheric motion. The presence of a gradient of pressure, which is a sort of fluid group self force, renders the accretion motion non-geodesic.In accretion motion back reaction effects are taken into consideration in numerical and simulation analyses [1][2][3]. Full analytical treatments [4-8] drop back reaction effects for simplicity and cognitive treatments [9-15] may include emission effects and neglect back reaction too.All the above-mentioned treatments make common simplificative physical assumptions of symmetry concerning both the given background geometry and the fluid. They assume the background metric to remain stationary and time-independent during accretion [16]. The analysis remains valid for accretion time, larger than free-fall time, and much smaller than the ratio mass/(mass rate change) of the star.In this work we will keep using the standard set of simplificative assumptions to describe the accretion of rotating perfect fluids onto rotating black holes with no back reaction or emission effects. In Sec. II we present the accretion model and in sec. III we derive the gen...

show abstract

Effects of Fluid Composition on Spherical Flows Around Black Holes

Cited by 83 publications

References 23 publications

Estimation of bipolar jets from accretion discs around Kerr black holes

Estimation of bipolar jets from accretion discs around Kerr black holes

Radiatively driven relativistic jets with variable adiabatic index equation of state

Accretion of rotating fluids onto stationary solutions

Contact Info

Product

Resources

About