BL Lac Objects: Proceedings of a Workshop Held in Como, Italy, September 20-23, 1988 (Lecture Notes in Physics)

This volume gives a comprehensible survey of BL Lac objects: contributors summarize observations on these interesting astrophysical objects and present theoretical models to explain them. Understanding these objects should help to give a better insight into the physics of black holes and relativistic plasmas. Topics addressed cover radio jets expanding at superluminal velocities, possible effects of relativistic jets on interstellar matter, the continuum emission over the whole electromagnetic system and its variability, and the impact of these observations on gravitational lensing and cosmological evolution. The book should be immensely useful for graduate students. Superluminal motion in quasars and BL Lac objects.- Statistics of superluminal sources.- VLBI polarization measurements of BL Lacertae objects.- Statistical properties of radio polarization of blazars.- The physical conditions and orientations of parsec-scale jets derived FROM CM-waveband variability data.- Radio variability of BL Lacs and related objects: Observations vs. shocked jet models.- The host galaxy of BL Lac objects or what’s in a name?.- Optical observations of a complete sample of radio selected BL Lac objects.- A spectroscopic study of blazars at medium resolution. Observations of PKS 0521-36, PKS 0537-44 and PKS 0823-22.- Beamed ionizing radiation in radio galaxies.- What are the emission line filaments along the radio axis of Centaurus A?.- Narrow band imaging close to the nuclei of BL Lac objects.- Anisotropic ionising continuum emission in AGNs.- Optical-infrared synchrotron emission in luminous AGN.- Polarization OF BL Lac objects.- Simultaneous UBVRI polarimetry of blazars.- Optical photometry and polarimetry of BL Lacertae objects.- An optical polarization survey for BL Lacs.- Long-term optical variability of BL Lac objects.- The nature of the rapid optical variability observed for BL Lacertae.- Energy distributions of blazars.- Radio and optical variability in blazars.- Simultaneous optical and IR observations of BL Lacertae objects.- Simultaneous optical and IR polarimetric observations of Blazars.- Multiwaveband observations of the Blazar 1156+295.- Recent activity in 3C 273.- Questions and comments.- BL Lacertae objects detected in the HEAO-1 all sky X-ray survey.- BL Lac objects from the extended medium sensitivity survey: The surface density.- BL Lacertae objects from the EXOSAT high galactic latitude survey: Constraints on the LogN-LogS and on the cosmological evolution.- The optical and radio properties of X-ray selected Bl Lacertae Objects.- Optical polarimetry of x-ray selected BL Lacs 1989.- Two new BL Lacertae objects discovered in the error boxes of hard X-ray sources.- Discovery of an X-ray selected optically highly variable quasar.- Einstein observatory X-ray spectra of BL Lac objects.- BL Lac objects as X-Ray sources: The Exosat observations.- The exosat spectral survey of BL Lacertae objects.- X-ray studies of BL Lac objects with Ginga.- Spectral components of BL Lac objects and other compact extragalactic radio sources.- The X-ray variability of PKS 2155-304: A power spectrum analysis.- Emission models of BL Lac objects.- On the energy dependent variability of BL Lac Objects.- Relativistic jet models for the BL Lacertae object Mrk 421 during three epochs of observation.- On the steep X-ray spectrumof BL Lac objects.- Models of OJ 287 based on optical monitoring.- On speed of jets.- The interaction of relativistic jets with the ambient radiation field.- Collimation and polarization of radiation through scattering by jets.- Accretion-disk models of BL Lac objects.- The relationship between BL Lacertae objects and other types of active and normal galaxies and quasi-stellar objects.- BL Lac objects, OW/HPQs and unified models.- The relation of BL Lac objects to QSOs and galaxies.- Is gravitational lensing important for BL Lac objects?.- Galaxies near distant quasars: Evidence for statistical gravitational lensing.- Relativistic beaming, luminosity functions, and the number counts of BL Lac objects.- Evolutionary BL Lacs ?.- A model for the evolution of quasars and BL Lacs.- Nature and evolution of BL Lac objects.- General discussion.