Bound Orbits and Epicyclic Motions around Renormalization Group Improved Schwarzschild Black Holes

• Published in: Universe (Basel) Vol. 8; no. 5; p. 278
• Main Authors: Lin, Hou-Yu, Deng, Xue-Mei
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.05.2022
• Subjects: alternative theories of gravity; astrometry; Black holes; Charged particles; general relativity; gravitation; Gravitational waves; Gravity; Magnetic fields; Orbits; Spacetime
• ISSN: 2218-1997; 2218-1997
• DOI: 10.3390/universe8050278

We study timelike particles’ bound orbits around renormalization group improved Schwarzschild black holes (RGISBHs), which originate from renormalization group improvement of the Einstein–Hilbert action by using the running Newton constant. By considering the secular periastron precession for the timelike particles orbiting around RGISBHs, we found that it is not feasible to distinguish such black holes from Schwarzschild ones in the weak gravitational field. However, in the strong gravitational field, periodic orbits for the particles are investigated by employing a taxonomy. This suggests that the variation of the parameters in RGISBHs can change the taxonomy. This leads to a transition from periodic motion around Schwarzschild black holes to a quasi-periodic motion around these black holes. After that, the epicyclic motions of charged particles around RGISBHs immersed in an external asymptotically uniform magnetic field are taken into account with respect to the observed twin peak quasi-periodic oscillations’ frequencies. The epicyclic motions of charged particles around such black holes in the external magnetic field can give one possible explanation for the 3:2 resonance in three low-mass X-ray binaries. Our results might provide some hints to distinguish RGISBHs from the classical black holes by using periodic orbits and epicyclic motions around the strong gravitational field.