VLBI and Compact Radio Sources

I.A.U. symposium No. 110 on VLBI and Compact Radio Sources was held in Bologna, Italy from June 27 to July 1, 1983. 166 participants from 19 countries were registered and 106 invited and contributed papers were registered. The scientific presentations and discussion concentrated on VLBI observation and interpretation of galactic and extragalactic radio sour­ ces, including topics as diverse as quasars and galactic nuclei, inter­ stellar masers, pulsars, and astrometry. Geodetic applications and tech­ nical development were treated only briefly, as these topics have been the subject of other recent international symposia. Since the first VLBI observations in 1967, sensitivity, resolution, and image quality have improved dramatically. Radio maps shown at the symposium were of comparable quality to conventional synthesis maps be­ ing made at the time of the first VLBI experiments 15 years ago, but with a resolution more than a factor of 1000 better. We wanted to accommodate the large number of contributed papers in this rapidly developing field, but there was inadequate time for normal oral presentations and discussion. We therefore asked that all contrib­ uted papers be put on display for at least 24 hours prior to a brief oral summary. A question and discussion period followed groups of oral pres­ entations on the same or similar topic. In this way the opportunity for interactive discussion, not available in conventional poster displays, was preserved.

Intermediate Scale Structure.- How to Choose a Randomly Oriented Sample.- Faint Extended Radio sources Surrounding Active Galaxy Nuclei.- VLBI Survey of a Complete Sample of Active Nuclei and Quasars.- Distortions in Compact Steep Spectrum Radio Sources.- The Milliarsecond Core of 3C147 at 6 cm.- Extragalactic VLBI at 89 GHz.- Milliarcsecond Polarization Measurements.- Cores in Extended Quasars.- 3C205 — A Sources with Extraordinary Alignment and a VLBI Hotspot.- VLBI Observations of 3C298.- Hot Spots in Compact Sources.- Sub-milliarcsecond Radio Structure of AO 0235+164.- The Variable HI Absorption (z = 0.524) in the Spectrum of AO 0235+164.- Multifrequency Observations of the BL Lac Object 1219+23.- Optically Quiet Quasars.- EVN Observations of Compact Steep Spectrum Radio Sources at 18 cm.- Steep Spectrum Radio Cores and Far-Sightedness.- Compact Doubles: a Genuine or Illusory Class?.- Spatial Structures of a Complete Sample of Extragalactic Radio Sources North of Declination 70°.- The Southern Hemisphere VLBI Experiment (SHEVE).- Statistical Properties of Compact Sources.- The Infrared, Optical and Ultraviolet Properties Of Active Nuclei.- X-Ray Properties of Extragalactic Compact Objects.- Superluminal Effects and Bulk Relativistic Motion.- VLBI Observations of the Superluminal Sources 3C 273 and 3C 279.- Superluminal Acceleration of the New Component in 3C 345.- A 10 Station VLBI Map of 3C147 at 1661 MHz.- Proper Motion of Components of the Quasar 3C 345.- Superluminal Motion in BL Lacertae : 10.65 GHz VLBI observations from 1981.7 to 1982.7.- The Radio Polarization of BL Lacertae: Shocks in a Jet.- Observations of Superluminal Motions in 3C 120.- 200 Milliarcsecond Structure in 3C 120.- VLBI Monitoring of BL Lac-Objects.- Multi-Epoch Observations of Survey Sources.- 4C39.25 — a Contracting Source ?.- The Nucleus of NGC1275.- The Radio Jet in 3C418.- Sub-Luminal Motions in the Nucleus of M 87.- Inner Oscillations in the M87 Jet.- The Structural Variations of 3C454.3 and 2134+004.- Evidence for Relativistic Motion Based on Arcsecond Structure.- Superluminal Motion in Weak Quasar Cores.- VLBI Observations of Weak Cores in Extended Quasars.- Extended Structure Around Superluminal and Other Core-Dominated Radio Sources.- The Low Frequency Variability of Extragalactic Radio Sources.- Dynamic Spectra of Low-Frequency Variables.- Daily Radio Frequency Observations of Selected Objects.- An Outburst of OJ 287.- Evidence of Doppler Beaming in Variable Radio Sources.- Evidence of Relativistic Beaming in BL LAC-Type Objects.- A Comparison of Compact and Extended Radio Sources in Three Wavebands.- Paschen Alpha as a Probe of Relativistic Beaming.- The Statistics of Bent Jets.- Explanations Of Superluminal Motion.- Physics of Relativistic Jets on Sub-Milliarcsecond Scales.- Theoretical Models of Active Galactic Nuclei.- A Nuclear Regula-Tori Model for Quasars and Seyferts.- Stability Properties of VLBI Jets.- Turbulent Cascade in VLBI Jets.- A Relativistic Wind-Type Model for the Generation of VLBI Jets.- Jets and Broad Emission Line Regions.- A New Geometry for Superluminal Motions.- VLBI Observations of the Gravitational-Lens Images of Q0957+561.- 1038+528 A,B : Phase-Reference and Spectral-Index Maps.- Gravitational Lenses and VLBI Structures.- Radio Nuclei in Nearby Galaxies.- Radio Activity in Bright E/SO Galaxies : NGC 3894.- The structure of the Radio Nucleus of M81.- Sub Arc second Components in Nearby Bright Galaxies at Metre-Wavelengths.- The Radio Core of Markarian 348.- The Galactic Center.- Mark III VLBI Observations of Pulsars.- VLBI Observations of Stellar Binary Systems.- The September 1982 Radio Outburst of Cyg X-3.- The Rate of Component Separation in SCO X-1.- Radio Flares from Circinus X-1.- Thermal Radio Stars and High-Resolution Radio Observations.- The Evolution of the Compact Radio Structure in SS433 Over A 16 Day Period.- Anomalous Ejection in SS433.- Jets in Molecular Clouds.- Interstellar Scattering.- Interstellar Broadening of Compact Low Galactic Latitude Radio Sources.- Circumstellar OH Masers.- Observations of Excited State OH Maser at 6.0 and 13.4 GHz.- Merlin Observations of the OH Maser Emission from IRC+10420.- VLBI Synthesis Observations of Circumstellar OH Masers.- The Structure of OH Maser Clouds Associated with Late-Type Stars.- The Spatial Structure of Silicon Monoxide Masers.- Structure of H2O Maser Outburst in Orion KL Nebula.- Magnetic Field Structure of Star Forming Regions: VLBI Spectral Line Results.- Proper Motions and Distances of Water Maser Complexes.- Radio Astrometry.- Pulsar Astrometry.- A New Way of Tying Together the Hipparcos Frame to the VLBI Extragalactic Frame : Astrometric Observations of Stellar Maser Sources.- Interrelation of Present Optical and Radio Reference Frames.- Nearly Microarcsecond Precision Differential Astrometry.- Accurate Positions of 120 Radio Sources with Declinations Above -45°.- VLBI Geodesy : Techniques and Recent Results.- Set Up and Testing of a Software Package for the Geodetic Analysis of VLBI Data.- The VLB Array.- The Canadian Long Baseline Array.- Proposed Very Long Baseline Interferometry at 103 MHz in India.- Orbiting VLBI : A Survey.- Orbiting Very Long Baseline Interferometer Demonstration Using the Tracking and Data Relay Satellite System.- The Quasat Project.- Discussion of the Papers Presented at the Symposium.- Subjects Index.- Objects Index.- Authors Index.