Connections between accretion disks and jets in accreting black holes are anticipated theoretically. In recent years, potential evidence for such connections has been emerging, most vividly in the convenient regime of stellar-mass black holes. In this contribution, various lines of evidence for disk–jet connections are briefly examined, from the standpoint of an observer focused on the role of ...

We use three dimensional magnetohydrodynamic simulations, in a pseudo-Newtonian potential, to study geometrically thin accretion disc flows crossing rms, the marginally stable circular orbit around black holes. We concentrate on vertically unstratified and isothermal disk models, but also consider a model that includes stratification. In all cases, we find that the sonic point lies just inside ...

The efficiency of thin disk accretion onto black holes depends on the inner boundary condition, specifically the torque applied to the disk at the last stable orbit. This is usually assumed to vanish. I estimate the torque on a magnetized disk using a steady magnetohydrodynamic inflow model originally developed by Takahashi et al. 1990. I find that the efficiency ǫ can depart significantly from...

Recent semi-analytic models have highlighted the role of AGN jets in regulating the formation of galaxies. In this paper, we present a new implementation of feedback due to active galactic nuclei (AGN) in cosmological hydrodynamic simulations of galaxy formation in which AGN feedback is assumed to heat the halo gas through the production of jets. Combining a theoretical model of mass accretion ...

The final merger of a pair of massive black holes in a galactic nucleus is compelled by gravitational radiation. Gravitational waves from the mergers of black holes of masses 105−7(1 + z)M⊙ at redshifts of 1 − 20 will be readily detectable by the Laser Interferometer Space Antenna (LISA), but an electromagnetic afterglow would be helpful in pinpointing the source and its redshift. Long before t...