The discovery of the ?rst case of superluminal radio jets in our galaxy in 1994 from the bright and peculiar X-ray source GRS 1915+105 has opened the way to a major shift in the direction of studies of stellar-mass accreting binaries. The past decade has seen an impressive increase in multi-wavelength studies. It is now known that all black hole binaries in our galaxy are radio sources and most likely their radio emission originates from a powerful jet. In addition to the spectacular events related to the ejection of superluminal jets, steady jets are known from many systems. Compared with their supermassive cousins, the nuclei of active galaxies, stellar-mass X-ray binaries have the advantage of varying on time scales accessible within a human life (sometimes even much shorter than a second). This has led to the ?rst detailed studies of the relation between accretion and ejection. It is even possible that, excluding their “soft” periods, the majority of the power in gal- tic sources lies in the jets and not in the accretion ?ows. This means that until a few years ago we were struggling with a physical problem, accretion onto compact objects, without considering one of the most important components of the system. Models that associate part of the high-energy emission and even the fast aperiodic variability to the jet itself are now being proposed and jets can no longer be ignored.

Astrophysics is said to have been born when Isaac Newton saw an apple drop in his orchard and had the electrifying insight that the Moon falls just like that apple. James Binney shows how the application of physical laws derived on Earth allows us to understand objects that exist on the far side of the Universe.

The aim of this thesis is to provide a multiwavelength perspective of the fundamental properties of quasars. It improves the statistical measure of quasar orientation and their black hole mass estimates by eliminating systematic biases. This work illustrates X-ray and optical-UV properties of some of the most highly accreting quasars. A crucial step to determine radio core dominance, an orientation indicator, is to get the most accurate measurement of the Doppler-boosted core of jets. The isotropic lobe emission likely contaminates the core measurements from large area surveys with poor resolution. I empirically show that orientation studies require high spatial resolution radio data. Because of various practical issues and variability considerations, optical emission provides a better normalization for the core dominance parameter than the extended emission. The black hole mass and accretion rate are the two most fundamental properties of quasars. Virial mass estimation from single-epoch spectra relies on the linear relationship between the broad line region size and continuum luminosity. More recent reverberation mapping results indicate deviation from the canonical radius-luminosity relationship that correlates with accretion rate. Using a radius-luminosity relationship that corrects the accretion rate bias, I establish a new prescription of virial mass estimates. I quantify the overestimation of the viral masses in the absence of accretion rate correction for quasars spanning a wide range of redshifts. The overestimation increases as redshift increases. Quasars that exhibit systematically smaller broad-line region size in the reverberation mapping studies also have higher accretion rates. They are ideal candidates to test for observable signatures of highly accreting disks. I examine the X-ray and optical-UV properties of a dozen super-Eddington accreting black holes that show extreme deviation from the canonical radius-luminosity relationship. Super-Eddington accreting sources demonstrate a steeper hard X-ray photon index compared to sub-Eddington accreting sources. The power-law slope between optical-UV and X-rays steepens as disk emission increases. These results illustrate that the disk-corona connection stays unchanged in quasars accreting at super-Eddington rates.

This book reviews the phenomenology displayed by relativistic jets as well as the most recent theoretical efforts to understand the physical mechanisms at their origin. Relativistic jets have been observed and studied in Active Galactic Nuclei (AGN) for about half a century and are believed to be fueled by accretion onto a supermassive black hole at the center of the host galaxy. Since the first discovery of relativistic jets associated with so-called "micro-quasars" much more recently, it has seemed clear that much of the physics governing the relativistic outflows in stellar X-ray binaries harboring black holes and in AGN must be common, but acting on very different spatial and temporal scales. With new observational and theoretical results piling up every day, this book attempts to synthesize a consistent, unified physical picture of the formation and disruption of jets in accreting black-hole systems. The chapters in this book offer overviews accessible not only to specialists but also to graduate students and astrophysicists working in other areas. Covered topics comprise Relativistic jets in stellar systems Launching of AGN jets Parsec-scale AGN jets Kiloparsec-scale AGN jets Black hole magnetospheres Theory of relativistic jets The structure and dynamics of the inner accretion disk The origin of the jet magnetic field X-ray observations, phenomenology, and connection with theory

It is over a quarter of a century since the discovery of out?ows from young stars. The intervening years have led to remarkable advances in our understanding of this phenomenon. Much of the progress can be attributed to advances in facilities and technologies, including not only larger telescopes but also improved instrument and detector performance. In addition protostellar out?ows have now been imaged from the ground and space at high spatial resolution, e. g. with HST, and at a wide - riety of wavelengths from X-rays to radio waves, revealing more and more about their physics. This veritable revolution in observation has been accompanied by an exponential growth in our ability to numerically simulate the launching and pro- gation of jets. Codes continue to improve: they now incorporate more physics and are increasingly ef?cient through, for example, techniques such as adaptive mesh re?nement and the use of parallel processing in cluster environments. Simulating the launching and propagation of a jet all the way from the vicinity of the star up to 4 several thousand AU (a size range of10 ) is now much closer. In more recent times, developments in observation, theory and numerical s- ulation have been joined by laboratory jet experiments reproducing, on centimetre scales, that which is seen in astrophysics to stretch for several parsecs.

This book describes and reviews observations and investigations of the unique object SS433 obtained after 23 years of studying the massive binary system.The main difference between SS433 and other known X-ray binaries is the action of a constant supercritical regime for the accretion of gas onto the relativistic star (most likely a black hole) which has led to the formation of a supercritical accretion disk and collimated relativistic jets. The properties of jets are to a large extent determined by their interaction with disk wind. The precession of the disk and jets as well as the eclipsing in the binary system make SS433 a unique laboratory for studies of mechanisms for the microquasar phenomenon. The author describes the main ideas and results emerging from studies of the formation of the jets and supercritical accretion disk in SS433.