Possible signature of the magnetic fields related to quasi-periodic oscillations observed in microquasars

Abstract

The study of quasi-periodic oscillations (QPOs) of X-ray flux observed in the stellar-mass black hole binaries can provide a powerful tool for testing of the phenomena occurring in the strong gravity regime. Magnetized versions of the standard geodesic models of QPOs can explain the observationally fixed data from the three microquasars. We perform a successful fitting of the HF QPOs observed for three microquasars, GRS 1915+105, XTE 1550-564 and GRO 1655-40, containing black holes, for magnetized versions of both epicyclic resonance and relativistic precession models and discuss the corresponding constraints of parameters of the model, which are the mass and spin of the black hole and the parameter related to the external magnetic field. The estimated magnetic field intensity strongly depends on the type of objects giving the observed HF QPOs. It can be as small as 10 −5 G if electron oscillatory motion is relevant, but it can be by many orders higher for protons or ions (0.02-1 G), or even higher for charged dust or such exotic objects as lighting balls, etc. On the other hand, if we know by any means the magnetic field intensity, our model implies strong limit on the character of the oscillating matter, namely its specific charge.

Harmonic oscillations of neutral particles in the γ metric

“…The frequencies of quasiperiodic oscillations in the Schwarzschild metric were studied for example in [16,17], while for the Kerr metric they have been studied in various physical scenarios, for example in [18][19][20]. The application to astrophysics and the study of astrophysical black holes was discussed in [21][22][23][24][25][26][27].…”

Orbital widening due to radiation reaction around a magnetized black hole

“…Oscillatory motion of charged particles and related circular orbits in magnetized Schwarzschild BH spacetime were studied by Frolov & Shoom () and Kološ et al (); in magnetized Kerr spacetime by Kološ et al (), Shiose et al (), and Tursunov et al (); and in magnetized “Ernst” metric by Lim (), as well as in other papers, e.g., Abdujabbarov & Ahmedov (), Abdujabbarov et al (), Abdujabbarov et al (), Al Zahrani et al (), Aliev & Gal'tsov (), Gal'tsov & Petukhov (), Rahimov et al (), Rayimbaev (2016), Shaymatov et al (), and Tursunov et al (). Resonant phenomena were extensively discussed in Stuchlík et al ().…”

“…The dynamics and the corresponding oscillatory motion of the charged particles in the absence of radiation reaction force in the magnetized Schwarzschild spacetime can be found in Kološ et al () and in the magnetized Kerr spacetime in Kološ et al () and Stuchlík & Kološ (). Let us introduce two dimensionless parameters characterizing the influences of the magnetic field and radiation reaction force in the BH's vicinity as follows: where q and m are charge and mass of a test particle, and M is the BH mass.…”

Particle motion around generic black holes coupled to non-linear electrodynamics

“…The main purpose of the studying the particle motion around compact objects is to test the model or solution of gravity theories. Particularly, the accretion disc around the astrophysical black holes is considered as a relevant model of some X-ray sources and the observation of inner edge radii of accretion disc can give constraints on parameters of alternative and modified theories of gravity [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39]. Above presented facts are good motivation for study test particle's motion around black hole described by the general relativistic solution coupled with non-linear electrodynamics.…”