Magnetised tori in the background of a deformed compact object

Abstract

The aim of this work is to study the relativistic accretion thick disc model raised by a deformed compact object that slightly deviated from spherical up to the quadrupole moment by utilising the q-metric. This metric is the simplest asymptotically flat solution of Einstein’s equation with quadrupole moment. We studied the effects of quadrupole moments in combination with the parameters of the thick magnetised disc model via studying the properties of these equilibrium sequences of magnetised, non-self-gravitating discs in this space-time. We employed different angular momentum distributions and discussed the procedure of building this toroidal disc model based on a combination of approaches previously considered in the literature. We show the properties of this relativistic accretion disc model and its dependence on the initial parameters. In addition, this theoretical model can serve as the initial data for numerical simulations.

Relativistic equilibrium fluid configurations around rotating deformed compact objects

“…However, a deeper analysis reveals that the growth rate caused by increasing a is higher than by increasing q. For the case a = 0 the result is in good agreement with the results found in [16] for a constant angular momentum. Furthermore, in the second column and row, we have the Schwarzschild case and we see that by changing these parameters, the configuration of the disk smoothly deviate from this particular choice a = 0 = q.…”

“…The next interesting physical aspect of compact objects is their rotation. Therefore, in the present work, as the next step of this work [16], we will consider a stationary generalization of the q-metric that contains an additional parameter, corresponding to the dipole of the angular momentum [20]. We explore the applicability of the stationary q−metric in astrophysical situations, we study an axially symmetric thick accretion disk model, which is situated on the background of a rotating, deformed mass distribution.…”

Retrograde polish doughnuts around boson stars

“…In the context of GRMHD simulations, for example, they are used as initial condition to investigate advection-dominated flows [50], weakly magnetized disks [51], jet formation [52], similarities and differences between BH and BS images [17,18,19] and so on. The doughnuts are also a starting point for many analytical studies, among which we would like to highlight the ones regarding accretion disks sheltered by less-mainstream spacetimes, like Kerr-de Sitter backgrounds [53], Kerr black holes with scalar hair [54], distorted static BHs [55], deformed compact objects [56] and also BSs [42].…”

Properties of accretion disc models in the background with quadrupoles

“…In Figure 3 this situation is plotted with constant angular momentum. However, with two other angular momentum distributions discussed in the paper it is also possible to have two tori 20 . Furthermore, in the trigonometric distribution, the σ and δ parameters influence each other.…”

“…Although the effect of quadrupoles correlates with the other parameters, we can conclude that quadrupoles are more responsible for shifting the position of the disc and have a positive contribution to its radial extension. However, this effect for β is not easy to see, as the values of quadrupole parameters that we chose in our models are minimal 20,21 . Moreover, there is a possibility of having two tori in a row for any value of β but negative values for the parameter α ∈ (−0.5, −0.553].…”