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

Abstract

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.

Spiral shocks induced in a galactic gaseous disk: Hydrodynamic understanding of observational properties of spiral galaxies

“…As a result, a part of the accreting matter is ejected as mass outflow from the disk due to the excess thermal gradient force across the shock. The accretion-ejection process has been widely investigated based on the shock compression model and considering an axisymmetric accretion flow assumption (Chattopadhyay & Das 2007;Das & Chattopadhyay 2008;Kumar & Chattopadhyay 2013;Aktar et al 2015Aktar et al , 2017Aktar et al , 2019. In the same spirit, Aktar et al (2021) investigated mass outflow from the disk induced by spiral shock compression in a nonaxisymmetric accretion flow.…”

Point-wise Self-similar Solution for Spiral Shocks in Accretion Disk with Mass Outflow in Binary

“…This model has been used to explain the observational spectral states and quasiperiodic oscillations of compact objects (Chakrabarti & Titarchuk 1995;Molteni et al 1996). The mass ejection (jets or outflows from disks) due to the shock compression has also been extensively investigated with this model in recent years (Chattopadhyay & Das 2007;Das & Chattopadhyay 2008;Kumar & Chattopadhyay 2013;Aktar et al 2015Aktar et al , 2017Aktar et al , 2019.…”

“…This makes the territory of self-similarity shrink to pointwise regions, and the solution becomes point-wise valid. Meanwhile, we also consider the mass outflow due to the compression of spiral shock according to the similar analyses in Aktar et al (2015Aktar et al ( , 2017Aktar et al ( , 2019. Therefore, our model is an analytical accretion-ejection model for the interactive binary, which includes the effects characterized by the parameters of binary and might be used in further studies of binary evolution (Wang 2018).…”