Қазақ ұлттық қыздар педагогикалық университеті / Казахский национальный женский педагогический университет

Постоянный URI для этого сообществаhttps://cris.qyzpu.edu.kz/handle/123456789/1

Просмотр

Фильтры

2023 - 20244

Настройки

Язык: search.filters.language.АнглийскийТема: search.filters.subject.quadrupole moment

Результаты поиска

Показано: 1 - 4 из 4
  • Загрузка...
    Изображение-миниатюра
    Некоторые метрики заблокированы вашими 
    настройками согласия
    Тип записи:Публикация,
    A shadows from the static black hole mimickers
    (Al-Farabi Kazakh National University, 2023-01-10)
    Aray Muratkhan
    ;
    Ayazhan Orazymbet
    ;
    Madina Zhakipova
    ;
    M. Assylbek
    ;
    Saken Toktarbay
    In this work, we study shadows from the naked singularity spacetime. The most analytical solutions of black hole shadows only investigated the case that the geodesic equations for photons can separate variables. We review the spherical null naked singularity metric and this spherically symmetric naked singularity spacetime metric is the solution of Einstein equations with an anisotropic fluid source which has no photon sphere. We also review a static, axially-symmetric singular solution of the vacuum Einstein’s equations without an event horizon which is can be used to describe the exterior gravitational field of a mass distribution with quadrupole moment. Moreover, the corresponding spacetime is characterized by the presence of naked singularities. It is theoretically known that not only a black hole can cast shadow, but other compact objects such as naked singularities, gravastar or boson stars can also cast shadows. We present the analytical calculation of shadows for both naked singularities spacetime and compare with the shadow of Schwarzschild static black hole, we show that this can serve as a black hole mimicker. Keywords: compact object, naked singularity, shadow.
    Цитирования (OpenAlex) 5
  • Загрузка...
    Изображение-миниатюра
    Некоторые метрики заблокированы вашими 
    настройками согласия
    Тип записи:Публикация,
    Gravitational Refraction of Compact Objects with Quadrupoles
    (Multidisciplinary Digital Publishing Institute, 2023-02-28)
    Nurzada Beissen
    ;
    Daniya Utepova
    ;
    Medeu Abishev
    ;
    Hernando Quevedo
    ;
    Manas Khassanov
    We use the material medium approach to derive the refractive index that can be associated with the gravitational field of a compact object with a quadrupole moment. We consider both a static deformation and a stationary rotation of the gravitational source as the source of the quadrupole. We show that up to the first order in the quadrupole, the refractive indices of both configurations are equivalent such that from the point of view of refraction, a mimicking effect can occur. This also holds at the level of the deflection angle. We argue that it is possible to use the refractive indices and the parameters of the trajectories of light rays that propagate in a gravitational field to determine the physical parameters of the source.
    Цитирования (OpenAlex) 10Цитирования (OpenCitations) 5
  • Загрузка...
    Изображение-миниатюра
    Некоторые метрики заблокированы вашими 
    настройками согласия
    Тип записи:Публикация,
    Application of GBT theorem for Gravitational deflection of light by Compact Objects
    (Al-Farabi Kazakh National University, 2023-03-13)
    Nurzada Beissen
    ;
    Daniya Utepova
    ;
    Aray Muratkhan
    ;
    Ayazhan Orazymbet
    ;
    Manas Khassanov
    One of the most renowned classical experiments that verifies the curved nature of space-time geometry is the bending of light. This phenomenon is extensively discussed in most textbooks on general relativity, with a clear and comprehensive explanation provided. In this study, we employ the material medium approach to determine the refractive index associated with the gravitational field of a compact object with a quadrupole moment. Our research presents a method for calculating the gravitational deflection angle for compact objects by utilizing the refractive index and the GBT theorem for an isotropic metric. This method is particularly important because it allows for the calculation of the deflection angle for both light and relativistic particles. The material medium approach enables us to consider the compact object's gravitational field as a medium with a refractive index. By applying this approach, we establish a relationship between the refractive index and the quadrupole moment of the compact object. We then utilize this relationship to calculate the deflection angle of light and relativistic particles.
    Цитирования (OpenAlex) 6Цитирования (OpenCitations) 3
  • Загрузка...
    Изображение-миниатюра
    Некоторые метрики заблокированы вашими 
    настройками согласия
    Тип записи:Публикация,
    The Influence of Deformation in Compact Objects on Redshift and Radar Echo Delay
    (Al-Farabi Kazakh National University, 2024-03-19)
    Nurzada Beissen
    ;
    D.S. Utepova
    ;
    V.N. Kossov
    ;
    S. Toktarbay
    ;
    M.K. Khassanov
    The analogy between optics and mechanics provides a unified way to describe particle motion in mechanics and light propagation in geometrical optics, and recent publications have demonstrated that this analogy can also be applied to general relativity, specifically when dealing with static metrics. In this paper, we use the material medium approach to obtain the refractive index associated with the gravitational field of a compact object having a quadrupole moment. Within this approach, we explore well-known effects of general relativity such as redshift and radar echo delay, deriving mathematical expressions for these phenomena taking into account the influence of the quadrupole moment.
    Цитирования (OpenAlex) 1