Magnetized SASI: its mechanism and possible connection to some QPOs in XRBs
arXiv:1712.02367 · doi:10.1093/mnras/sty488
Abstract
The presence of a surface at the inner boundary, such as in a neutron star or a white dwarf, allows the existence of a standing shock in steady spherical accretion.The standing shock can become unstable in 2D or 3D; this is called the {\em standing accretion shock instability} (SASI).Two mechanisms -- advective-acoustic and purely acoustic -- have been proposed to explain SASI. Using axisymmetric hydrodynamic (HD) and magnetohydrodynamic (MHD) simulations, we find that the advective-acoustic mechanism better matches the observed oscillation timescales in our simulations. The global shock oscillations present in the accretion flow can explain many observed high frequency ( Hz) quasi-periodic oscillations (QPOs) in X-ray binaries (XRBs). The presence of a moderately strong magnetic field adds more features to the shock oscillation pattern, giving rise to low frequency modulation in the computed light curve. This low frequency modulation can be responsible for Hz QPOs (known as hHz QPOs). We propose that the appearance of hHz QPO determines the separation of twin peak QPOs of higher frequencies.
21 pages, 23 figures, 1 table, published in MNRAS
References in corpus (13)
- PLUTO: a Numerical Code for Computational Astrophysics
- Delayed neutrino-driven supernova explosions aided by the standing accretion-shock instability
- Instability of a stalled accretion shock: evidence for the advective-acoustic cycle
- Pulsar spins from an instability in the accretion shock of supernovae
- Multidimensional supernova simulations with approximative neutrino transport. II. Convection and the advective-acoustic cycle in the supernova core
- X-ray time variability across the atoll source states of 4U 1636--53
- Effect of Rotation on the Stability of a Stalled Cylindrical Shock and its Consequences for Core-Collapse Supernovae
- Effects of Rotation on Standing Accretion Shock Instability in Nonlinear Phase for Core-Collapse Supernovae
- Linear growth of spiral SASI modes in core-collapse supernovae
- Is there a link between the neutron-star spin and the frequency of the kilohertz quasi-periodic oscillations?
- Modeling core collapse supernovae in 2 and 3 dimensions with spectral neutrino transport
- Are pulsars spun up or down by SASI spiral modes?
- Observational evidences for spinning black holes: A proof of general relativity for spacetime around rotating black holes