Probing the space-time geometry around black hole candidates with the resonance models for high-frequency QPOs and comparison with the continuum-fitting method
Astrophysical black hole candidates are thought to be the Kerr black hole predicted by General Relativity. In order to confirm the Kerr-nature of these objects, we need to probe the geometry of the space-time around them and see if the observations are consistent with the predictions of the Kerr metric. That can be achieved, for instance, by studying the properties of the electromagnetic radiation emitted by the gas in the accretion disk. The high-frequency quasi-periodic oscillations observed in the X-ray flux of some stellar-mass black hole candidates might do the job. As the frequencies of these oscillations depend only very weakly on the observed X-ray flux, it is thought they are mainly determined by the metric of the space-time. In this paper, I consider the resonance models proposed by Abramowicz and Kluzniak and I extend previous results to the case of non-Kerr space-times. The emerging picture is more complicated than the one around a Kerr black hole and there is a larger number of possible combinations between different modes. I then compare the bounds inferred from the twin peak high-frequency quasi-periodic oscillations observed in three micro-quasars (GRO J1655-40, XTE J1550-564, and GRS 1915+105) with the measurements from the continuum-fitting method of the same objects. For Kerr black holes, the two approaches do not provide consistent results. In a non-Kerr geometry, this conflict may be solved if the observed quasi-periodic oscillations are produced by the resonance $ν_θ: ν_r = 3:1$, where $ν_θ$ and $ν_r$ are the two epicyclic frequencies. It is at least worth mentioning that the deformation from the Kerr solution required by observations would be consistent with the one suggested in another recent work discussing the possibility that steady jets are powered by the spin of these compact objects.
Probing black holes surrounded by Dust field in Quantum Fluctuation Modified Gravity with twin-peak QPOs
National University of Uzbekistan（乌兹别克斯坦国立大学）；Samarqand State Pedagogical Institute（撒马尔罕国立师范学院）；Institute of Fundamental and Applied Research, National Research University TIIAME（塔什干信息技术与管理系统国立研究大学基础与应用研究所）；Tashkent State Technical University（塔什干国立技术大学）；School of Physics, Harbin Institute of Technology（哈尔滨工业大学物理学院）；University of Tashkent for Applied Sciences（塔什干应用科学大学）；Institute of Theoretical Physics, National University of Uzbekistan（乌兹别克斯坦国立大学理论物理研究所）；New Uzbekistan University（新乌兹别克斯坦大学）；Kimyo International University in Tashkent（塔什干基莫国际大学）；University of Economics and Pedagogy（经济与教育学院）；Tashkent International University（塔什干国际大学）
Probing quantum corrected black hole through astrophysical tests with the orbit of S2 star and quasiperiodic oscillations
Institute of Fundamental and Applied Research, National Research University TIIAME（国立研究大学TIIAME基础与应用研究所）；Institute for Theoretical Physics & Cosmology, Zhejiang University of Technology（浙江工业大学理论物理与宇宙学研究所）；University of Tashkent for Applied Sciences（塔什干应用科学大学）；Center for Theoretical Physics, Khazar University（哈扎尔大学理论物理中心）；School of Physics, Harbin Institute of Technology（哈尔滨工业大学物理学院）；Institute for Advanced Studies, New Uzbekistan University（新乌兹别克斯坦大学高级研究所）；Institute of Theoretical Physics, National University of Uzbekistan（乌兹别克斯坦国立大学理论物理研究所）；United Center for Gravitational Wave Physics (UCGWP), Zhejiang University of Technology（浙江工业大学引力波物理联合中心）
Probing Kerr black hole in a uniform Bertotti-Robinson magnetic field through astrophysical quasi-periodic oscillations
Institute for Theoretical Physics and Cosmology, Zhejiang University of Technology（浙江工业大学理论物理与宇宙学研究所）；United Center for Gravitational Wave Physics (UCGWP), Zhejiang University of Technology（浙江工业大学联合引力波物理中心）；Center for Theoretical Physics, Khazar University（哈萨克斯坦大学理论物理中心）；Institute of Fundamental and Applied Research, National Research University TIIAME（国立研究大学塔什干信息技术与应用科学大学基础与应用研究所）；Tashkent University of Applied Sciences（塔什干应用科学大学）；Tashkent State Technical University（塔什干国立技术大学）
Precessions and parameter constraints from quasiperiodic oscillations in a rotating charged black hole
Center for Gravitation and Cosmology, College of Physical Science and Technology, Yangzhou University（扬州大学物理科学与技术学院引力与宇宙学中心）；School of Physics and Electronic Information Engineering, Neijiang Normal University（内江师范学院物理与电子信息工程学院）；Particle Theory and Cosmology Group, Center for Theoretical Physics of the Universe, Institute for Basic Science (IBS)（基础科学研究院宇宙理论物理中心粒子理论与宇宙学组）
