Sources and scintillations : refraction and scattering in radio astronomy : IAU Colloquium 182

The genesis of IAU Colloquium 182, 'Sources and scintillations: refraction and scattering in radio astronomy,' can be traced to the desire, on the one hand, of Beijing Astronomical Observatory radio astronomers to organize a conference which would highlight the need for high sensitivity - as a way ofpromoting their own project to build the world's largest telescope (FAST) - and to a suggestion from Ron Ekers on the other. During a discussion with the two SOC co-chairs (as they then were not) in January 1999 in Epping, Ron noted the success ofa meeting on 'radio seeing' in Beijing in 1989, and wondered whether the time might not be ripe to organize another conference devoted to radio propagation. This set the ball rolling, and with enthusiastic input from SOC members, a successful application was made to the IAU. Later, the URSI also agreed to co-sponsor the meeting. From April 17-21, 2000, over 80 astronomers from a dozen countries met in Guiyang, China, to discuss the latestexciting results and theoretical ideas on radio propagation through interstellar, intergalactic and interplanetary space. These pro­ ceedings include almost all (95%) ofthe oral presentations given at the conference. In addition to the 52 talks presented during 5 days of the Colloquium, Ron Ekers gave a fine summary at the end to tie things up. There were also poster sessions where some twenty papers were displayed. Besides the scientific sessions, the LOC had organized a program for spouses and otheraccompanying persons. Front Matter....Pages i-2 Front Matter....Pages 3-3 Radio Sources and Scintillation....Pages 5-10 The Galactic Distribution of Electron Density Microstructure Inferred from Radio Scattering Observations....Pages 11-16 Incompressible MHD Turbulence....Pages 17-23 Pulsar Scintillation: Overview and Some Recent Results....Pages 25-30 Front Matter....Pages 31-31 The Parkes Multibeam Pulsar Survey and Interstellar Scattering....Pages 33-38 The Study of Scattering Effects by VLBI Observations of PSR 0329+54 with HALCA at 1650 MHZ....Pages 39-42 Frequency Structure of Radio Scintillations for Several Pulsars....Pages 43-46 Optimizing Pulsar Searches Against Propagation Effects....Pages 47-52 Scattering Of The Low Frequency Pulsar Radiation....Pages 53-56 Scintillation Observations Of Strong Northern Pulsars....Pages 57-60 Giant Radio Pulses from Pulsars....Pages 61-64 Studying Pulsar Emission Regions Using Interstellar Scattering....Pages 65-70 Pulsar Investigation Using Interstellar Scintillation....Pages 71-75 Propagation of Electromagnetic Waves in Pulsar Magnetospheres....Pages 77-80 Looking Into Pulsar Magnetospheres....Pages 81-84 Front Matter....Pages 85-85 Radio Intra-Day Variability: Answers and Questions....Pages 87-92 Variability Observations of a Complete Sample of Flat-Spectrum Radio Sources: Preliminary Results....Pages 93-96 VSOP Observations of the BL LAC Object 2007+777....Pages 97-100 Monitoring the Microarcsecond Quasar J1819+3845....Pages 101-104 Multi-Frequency Studies Of Intrinsic Intraday Variability....Pages 105-111 Front Matter....Pages 85-85 Examples of Extreme Intraday Variability....Pages 113-117 Multifrequency Polarization Variations in 0917+624....Pages 119-122 Gravitational Lensing....Pages 123-128 ISS of Polarized Compact Extragalactic Radio Sources....Pages 129-134 Strong, Variable Circular Polarization in PKS 1519-273....Pages 135-138 The Microarcsecond Quasar J1819+3845: Polarization Observations and Detailed Light Curve Analysis....Pages 139-142 Magnetic Fields in Quasar 3C147 on Milliarcsecond Scales....Pages 143-146 Front Matter....Pages 147-147 Interpretation of Extreme Scattering Events....Pages 149-154 Extreme Scattering Events: An Observational Summary....Pages 155-158 An ESE Event for PSR 0329+54....Pages 159-162 Interstellar Scintillation and Clouds of the Interstellar Turbulent Plasma....Pages 163-169 Interstellar Scintillation Studies of Pulsars and Distribution of Scattering Plasma in the Local Interstellar Medium....Pages 171-174 The Radio Luminosity of Pulsars and the Distribution of Interstellar Electron Density....Pages 175-179 Magnetic Fields in our Galaxy: How Much Do We Know?....Pages 181-184 Investigations Of AGNs by the Interplanetary Scintillation Method....Pages 185-188 IPS Observations at Miyun Station, BAO....Pages 189-192 VLA Observations of Angular Broadening Close to the Sun....Pages 193-196 Front Matter....Pages 197-197 On Post-SKA Radio Astronomy....Pages 199-204 Australian Research Effort for the SKA....Pages 205-208 Active Adaptive Arrays: The Astron Approach to SKA....Pages 209-212 Front Matter....Pages 197-197 The FAST/SKA Site Selection in Guizhou Province....Pages 213-218 Five-Hundred-Meter Aperture Spherical Telescope Project....Pages 219-224 Analysis for Reflector Aluminum Mesh Panels of Five-Hundred Meter Aperture Spherical Telescope....Pages 225-230 Structural Analysis of Fast Reflector Supporting System....Pages 231-236 Modelling, Simulation and Testing of an Optomechatronics Design of a Large Radio Telescope....Pages 237-242 On the Cable Car Feed Support Configuration for Fast....Pages 243-247 Trying to Enlarge the Sky Coverage of the Fast....Pages 249-253 Extending the Observable Zenith Angle of Fast Using an Offset Feed....Pages 255-259 The Control System of the Active Main Reflector for Fast....Pages 261-265 The topics covered in this book include: Theory of Scattering and Scintillation, Distribution of Scattering Material, Intra-day Variability, Pulsars and their Magnetospheric Structure, Polarization of AGN, Interplanetary Scintillation, and Future Highly-Sensitive Radio Telescopes. The introductory papers emphasize the essential properties of diffractive and refractive scattering, how they differ in temporal and frequency structure, and what they reveal about irregularities in the ISM. Pulsars can be examined in a number of different ways as a function of frequency: time variability (both short and long term), DM changes, pulse broadening, angular extent, and Faraday rotation. Intra-day variable sources (IDVs) are another major topic of the book. Although many variable sources clearly exhibit intrinsic changes, IDVs are generally believed to result from scintillation effects. They require source sizes on the ten micro-arcsec scale, the most extreme cases having profound implications for source lifetimes and emission mechanisms. Finally, a dozen contributions describe future large radio telescope projects, especially the Chinese FAST effort to build a 500 m spherical reflector of innovative design. Contains papers which emphasize the essential properties of diffractive and refractive scattering, how they differ in temporal and frequency structure, and what they reveal about irregularities in the ISM. This book also focuses on Intra-day variable sources (IDVs) and includes contributions which describe large radio telescope projects.