2015/01/29 by Li Xue, Xue, Li, Wlodek Kluzniak +7
Physics and Astronomy · #FOS: Physical sciences #High Energy Astrophysical Phenomena (astro-ph.HE) #astro-ph.HE
paper · pdf · doi:10.48550/arxiv.1501.07482
14 pages, 1 table, 4 figures, submitted to ApJLett
arxiv created 2015/01/29 · arxiv updated 2015/01/30
We numerically investigate the thermally unstable accretion disks around black holes. We adopt an evolutionary viscous stress equation to replace the standard alpha-prescription based on the results of two MHD simulations. We find a kind of interesting oscillations on some running models in limit-cycle outburst state. The oscillations arise near the inner boundary and propagate radially outwards. We deem that they are the trapped p-mode oscillations excited by sonic-point instability. We directly integrate the local radiation cooling fluxes to construct the mimic bolometric light-curve. We find a series of overtones beside the fundamental harmonic on the power spectra of mimic light-curves. The frequency of the fundamental harmonic is very close to the maximum epicyclic frequency of the disk and the frequency ratio of the fundamental harmonic and overtones is a regular integer series. We suggest that the code for ray-tracing calculation must be time-dependent in virtual observation and point out the robustness of the black hole spin measurement with high frequency QPOs.