Modified models of radiation pressure instability in application to 10, 10$^5$, and 10$^7$ $M_{\odot}$ accreting black holes

Abstract

Context. Some of the accreting black holes exhibit much stronger variability patterns than the usual stochastic variations. Radiation pressure instability is one of the proposed mechanisms which could account for this effect. Aims. We aim to model luminosity changes for objects with black hole mass of 10, 10 5 , and 10 7 solar masses, using the time-dependent evolution of an accretion disk unstable due to the dominant radiation pressure. We explore the influence of the hot coronal flow above the cold disk, the inner purely hot flow, and the effect of magnetic field on the time evolution of disk-corona system. In the case of Intermediate Mass Black Holes and AGN we also explore the role of the disk outer radius, motivated by the fact that the disk fed by Tidal Disruption Events can be quite small in size. Methods. We use a 1-dimensional, vertically integrated time-dependent numerical scheme which models simultaneous evolution of the disk and corona, coupled by the vertical mass exchange. We parameterize the strength of large-scale toroidal magnetic fields according to a local accretion rate. We also discuss the possibility of presence of an inner optically thin flow, namely the Advection-Dominated Accretion Flow (ADAF) which requires modification of the inner boundary condition of the cold disk flow. For the set of the global parameters we calculate the variability timescales and outburst amplitudes of the disk and the corona. Results. We found that the role of the inner ADAF and the accreting corona are relatively unimportant but the outburst character strongly depends on the magnetic field and the outer radius of the disk if this radius is smaller (due to TDE phenomenon) than the size of the instability zone in a stationary disk with infinite radius. For microquasars, the dependence on the magnetic field is monotonic, and the period decreases with the field strength. For larger black hole masses, the dependence is non-monotonic, and initial rise of the period is later replaced with the relatively rapid decrease as the magnetic field continues to rise. Still stronger magnetic field stabilizes the disk. Assumption of the smaller disk outer radius considered for 10 5 , and 10 7 M shortens the outbursts and for some parameter range leads to complex multi-scale outbursts thus approaching the deterministic chaos behaviour. Conclusions. Our computations confirm that the radiation pressure instability model can account for heartbeat states in microquasars. Rapid variability detected in IMBH in the form of Quasi-Periodic Ejection can be consistent with the model but only if combined with TDE phenomenon. Yearly repeating variability in Changing Look AGN also requires, in our model, small outer radius either due to the recent TDE or due to the presence of the gap in the disk related to the presence of a secondary black hole.