2 papers
gr-qc2020
Mass-spin relation of black holes obtained by twin high-frequency quasi-periodic oscillations
Ivan Zhivkov Stefanov
The paper studies the uniqueness and the monotonicity of the mass-spin relation of black holes the X-ray power density spectra of which contain twin high-frequency quasi-periodic o…
astro-ph.HE2020
X-ray quasi-periodic oscillations and estimates of the mass and the spin of the neutron star in 4U 1728-34
Ivan Zh. Stefanov
Three of the averaged light curves from the X-ray spectrum of 4U 1728-34 contain triads of quasi-periodic oscillations: two kHz, an upper and a lower one, and one low-frequency. In…