The Coupling Of Accretion With Jet In Black Hole Systems

Observations reveal that many black hole accreting systems show powerful outflowsof mass and energy. Recently, much attention has been paid to disk-jet coupling in blackhole accreting systems. Many evidences for this coupling have been emerging intheoretical modeling, numerical simulation and observation of multi-wavelengthlightcurves for the correlation radio flux with X-rays flux of the black hole binaries andAGNs.Black hole accretion is one of the most powerful sources of energy in the Universe.Up to now, a variety of black hole accretion disk models have been worked out. Based onradiative efficiency accretion flows can be divided into two major classes: the thinaccretion disk and the hot thick accretion disk (e.g. ADAF). The former can radiate itsenergy away so efficiently that it can be used to explain the very high luminosity of theblack hole X-ray binaries and AGNs. By contrast, the latter has very low radiativeefficiency and so dim luminosity, but very hot two-temperature plasma. Thus, the hotthick disk is applicable to the low luminosity and non-thermal spectrum of black holeX-ray binaries and LLAGNs. We briefly introduce the general relativistic thin accretiondisk and ADAF.In Chapter 2, we give a detailed introduction of the Blandford-Payne (BP)mechanism. In particular, we give emphasis to the launching and centrifugal accelerationphases and infer the outflow conservation equations of angular momentum and energybased on the equations for stationary ideal MHD. In the BP process, the outflow is mainlycentrifugal accelerated from the disk up to the Alfven surface and carries both kinetic andmagnetic energy. Part of the Poynting flux is converted into a kinetic energy flux duringthe acceleration process. Furthermore, we briefly introduce other energy mechanismsinvoking large-scale magnetic fields, i.e., the Blandford-Znajek (BZ), Disk-Load (DL) andmagnetic coupling (MC) processes.In Chapter 3, we propose a simplified model, in which disk accretion is combinedwith two mechanisms of extracting energy magnetically from black hole accretion disk,i.e., the Blandford-Payne (BP) process and the Blandford-Znajek (BZ) process. Incorporating the BP process with the conservation laws of mass, angular momentum andenergy, we derive the expressions of the BP power and disk luminosity, and the jet poweris regarded as the sum of the BZ and BP powers. We find that the disk radiation flux andluminosity decrease due to a fraction of accretion energy channeled into the outflow/jet inthe BP process. It is found that the dominative cooling mode of the accretion disk isdetermined mainly by the decreasing way of the poloidal magnetic field with thecylindrical radius of the jet. And the BP process is not so strong due to the stability of thethin disk. Thus the jet power does not dominate over the disk luminosity. This can be usedto explain the total jet power is of the same order as the accretion power for blazars. Inaddition, we fit the jet power and broad line region luminosity of 11 flat-spectrum radioquasars (FSRQs) and 17 steep-spectrum radio quasars (SSRQs) based on our model.In Chapter 4, we propose a simplified model of outflow/jet driven by theBlandford-Payne (BP) process from advcction dominated accretion flows (ADAF) andderive the expressions of the BP power and disk luminosity based on the conservationlaws of mass, angular momentum and energy. We fit the 2-10 keV luminosity and kineticpower of 15 AGNs of sub-Eddington luminosity. It is found that there exists ananticorrelation between the accretion rate and the advection parameter, which could beused to explain the correlation between Eddington-scalcd kinetic power and bolometricluminosity of the 15 samples. In addition, the Ledlow-Owen relation for FRⅠ/Ⅱdichotomy is re-expressed in a parameter space consisting of logarithm of dimensionlessaccretion rate versus that of the BH mass. It turns out that the FRⅠ/Ⅱdichotomy isdetermined mainly by the dimensionless accretion rate, being insensitive to the BH mass.And the dividing accretion rate is less than the critical accretion rate for ADAFs,suggesting that FRⅠsources arc all in the ADAF state.In Chapter 5, we discuss two kinds of magnetic connection in black hole (BH)accretion disc: the magnetic connection between the BH and the disc (MCHD) and thatbetween the plunging region and the disc (MCPD). The magnetic field configuration isproduced by an electric current flowing at the inner edge of the disc. It turns out that thetransfer direction of energy and angular momentum depends on the BH spin and aparameterλfor adjusting the angular velocities of the plunging matter, whichcorresponds to at most five regions in thc disc. The effect of MCPD results in a much steeper emissivity than a standard accretion disk in the inner disc, however it fails to reachthe observation range 4.3-5.5 in several objects, such as Seyfert 1 galaxy MCG-6-30-15,microquasars XTE J1650-500 and GX 399-4.In the last Chapter, we summarize the main results and point out some aspects to beimproved in our future work.