Can modified gravity silence radio-loud pulsars?

Rayimbaev, Javlon; Tadjimuratov, Pulat

doi:10.1103/physrevd.102.024019

Cited by 24 publications

(6 citation statements)

References 67 publications

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“…The analysis of observational data from rotation curves of the nearby galaxies has allowed getting constraint on the upper value of MOG parameter as α = 8.89 ± 0.34 [38]. The upper limit for the MOG parameter for the millisecond pulsars J2145-0750, J0024-7204D, and J0024-7204H, has been found as α 1.6011, 3.06528, and 0.9747, respectively, have been recently obtained in our previous paper [45]. Now we explore the event horizon properties of the regular MOG BH governed by the lapse function (8) with nonvanishing MOG parameter α.…”

Section: The Spacetime Propertiesmentioning

confidence: 66%

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Dynamics of Test Particles and Twin Peaks QPOs around Regular Black Holes in Modified Gravity

et al. 2021

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In this work, we have presented a detailed analysis of the event horizon of regular black holes (BHs) in modified gravity known as MOG, the so-called regular MOG BH. The motion of neutral particles around the BH has also been explored. The test particle motion study shows that the positive (negative) values of the MOG parameter mimic the spin of a rotating Kerr BH, providing the same values for the innermost stable pro-grade (retrograde) orbits of the particles in the range of the spin parameter a/M∈(−0.4125,0.6946). The efficiency of energy release from the accretion disk by the Novikov–Thorne model has been calculated, and the efficiency was shown to be linearly proportional to the increase of the MOG parameter α. Moreover, we have developed a new methodology to test gravity theories in strong-field regimes using precision data from twin-peaked quasiperiodic oscillations (QPOs) of objects calculating possible values of upper and lower frequencies. However, it is obtained that the positive MOG parameter can not mimic the spin of Kerr BHs in terms of the same QPO frequencies. We have provided possible ranges for upper and lower frequencies of twin-peak QPOs with the ratio of the upper and lower frequencies of 3:2 around regular MOG BHs in the different models. Moreover, as an example, we provide detailed numerical analysis of the QPO of GRS 1915+105 with the frequencies νU=168±5Hz and νL=113±3Hz. It is shown that the central BH of the QPO object can be a regular MOG BH when the value of the parameter is α=0.2844−0.1317+0.0074 and shines in the orbits located at the distance r/M=7.6322−0.0826+0.0768 from the central BH. It is also shown that the orbits where QPOs shine are located near the innermost stable circular orbit (ISCO) of the test particle. The correlation between the radii of ISCO and the QPO orbits is found, and it can be used as a new theoretical way to determine ISCO radius through observational data from the QPOs around various compact objects.

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Section: The Spacetime Propertiesmentioning

confidence: 66%

“…The role of the MOG field on plasma magnetospheric radiation from rotating magnetized relativistic stars and magnetized particles motion around gravitating compact objects have also been discussed in refs. [45,46].…”

Section: Introductionmentioning

confidence: 99%

Dynamics of Test Particles and Twin Peaks QPOs around Regular Black Holes in Modified Gravity

et al. 2021

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“…[28]. In past years, different properties of the electromagnetic fields in the vicinity of black holes immersed in external asymptotically uniform magnetic fields and proper magnetic field of rotating magnetized neutron stars with the dipolar structure were widely studied by several authors in different models of gravity [29][30][31][32][33][34][35][36][37][38][39]. This electromagnetic field will change the dynamics of charged particle in a close black hole environment [40][41][42][43][44][45][46][47].…”

Section: Introductionmentioning

confidence: 99%

Distinguishing magnetically and electrically charged Reissner–Nordström black holes by magnetized particle motion

et al. 2021

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In the present paper, we investigate the dynamics of magnetized particles around magnetically and electrically Reissner–Nordström (RN) black hole. The main idea of the work is to distinguish the effects of electric and magnetic charges of the RN black hole and spin of the rotating Kerr black hole through the dynamics of the magnetized particles. In this study, we have treated a magnetized neutron star as a magnetized test particle, in particular, the magnetar SGR (PSR) J1745-2900 orbiting around the supermassive black hole Sagittarius A* (SMBH SgrA*) with the magnetic interaction parameter $$b=0.716$$ b = 0.716 and the parameter $$\beta =10.2$$ β = 10.2 . The comparison of the effects of the magnetic and electric charges, and magnetic interaction parameters on the dynamics of the magnetar modeled as a magnetized particle near the SMBH Sgr A* has shown that the magnetic charge of the RN black hole can mimic the spin parameter of a rotating Kerr black hole up to $$a/M \simeq 0.82$$ a / M ≃ 0.82 . The external magnetic field can mimic the magnetic charge of the RN black hole up to $$Q_m/M=0.4465$$ Q m / M = 0.4465 . We have shown that the electric charge of the RN black hole can mimic the black hole magnetic charge up to $$Q_m/M=0.5482$$ Q m / M = 0.5482 and the magnetic field interaction with the magnetized particle acts against the increase of the mimicking value of the black hole spin parameter. The studies may be helpful to explain the observability of radio pulsars around the SMBH SgrA* system and taking it as a real astrophysical laboratory to get more precise constraints on the central black hole and dominated parameters of the alternate gravity. Finally, we have investigated the effects of magnetic and electric charge of the RN black hole in the center-of-mass energy of head-on collisions of magnetized particles with neutral, electrically charged, and magnetized particles. Both electric and magnetic charges of the RN black hole would lead to an increase in the center of the mass–energy of the collisions.

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“…The Kerr black hole (BH) geometry changes the structure of the asymptotically-uniform magnetic field in its close vicinity [1]. The pioneering work of Wald [1] has initiated the study of properties of the electromagnetic field around axial-symmetric BHs and magnetized neutron stars (see, e.g., [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]).…”

Section: Introductionmentioning

confidence: 99%

Magnetized Particle Motion in γ-Spacetime in a Magnetic Field

et al. 2020

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In the present work we explored the dynamics of magnetized particles around the compact object in γ-spacetime in the presence of an external asymptotically-uniform magnetic field. The analysis of the circular orbits of magnetized particles around the compact object in the spacetime of a γ-object immersed in the external magnetic field has shown that the area of stable circular orbits of magnetized particles increases with the increase of γ-parameter. We have also investigated the acceleration of the magnetized particles near the γ-object and shown that the center-of-mass energy of colliding magnetized particles increases with the increase of γ-parameter. Finally, we have applied the obtained results to the astrophysical scenario and shown that the values of γ-parameter in the range of γ∈(0.5,1) can mimic the spin of Kerr black hole up to a≃0.85, while the magnetic interaction can mimic the γ-parameter at γ∈(0.8,1) and spin of a Kerr black hole up to a≃0.3.

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Can modified gravity silence radio-loud pulsars?

Cited by 24 publications

References 67 publications

Dynamics of Test Particles and Twin Peaks QPOs around Regular Black Holes in Modified Gravity

Dynamics of Test Particles and Twin Peaks QPOs around Regular Black Holes in Modified Gravity

Distinguishing magnetically and electrically charged Reissner–Nordström black holes by magnetized particle motion

Magnetized Particle Motion in γ-Spacetime in a Magnetic Field

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