The Pearson-Readhead Survey from Space
We are using the VSOP mission to observe a complete sample of Pearson-Readhead survey sources at 4.8 GHz to determine core brightness temperatures and pc-scale jet properties.
Radio↗
Engineering topics
Lister, M.
Publications and source records attributed to Lister, M..
Scientific Results from the VSOP Space VLBI Mission
Explore the source record for details and available documents.
quasars VLBI↗
Intrinsic Differences in the Inner Jets of High and Low Optically Polarized Radio Quasars
We have conducted a high-resolution polarization study with the VLBA at 22 and 43 GHz to look for differences in the parsec-scale magnetic field structures of 18 high- and low-optically polarized, compact radio-loud quasars (HPQs and LPRQs, respectively).
VLBI polarization quasars magnetic fields shock wa↗
Predictions of ECS and SSC Emission Models for Flux-Limited Samples of Gamma-Ray Blazars
The external Compton scattering (ECS) and synchrotron self-Compton (SSC) models make distinct predictions for the amount of Doppler beaming of gamma-rays emitted by blazars.
Quasars active galaxies↗
The Pearson-Readhead Survey from Space
The VSOP Space VLBI mission uses the HALCA spacecraft, launched from Japan in February 1997, in conjunction with ground radio observatories around the world to create a high resolution radio-wave length imaging facility. We are using this unique facility to observe a complete sample of Pearson-Readhead Survey sources at 4.8 GHz to determine core brightness temperatures and pc-scale jet properties. The Pearson-Readhead sample has been used for extensive ground-based VLBI survey studies. This sample is ideal for a VSOP survey because the sources are strong, the VSOP u-v coverages are especially good above +350 declination, and multi-epoch ground-based VLBI data and other existing supporting data on these sources exceeds that of any other possible sample. We have chosen to observe a complete subset of this sample that is most likely to show fringes on space-earth baselines. To date we have imaged a majority of the 31 sources in our sample. In addition, we are obtaining matched- resolution 15 GHz observations using the VLBA at epochs close in time to the space VLBI observations to investigate the spectral indices of the source components at high resolution. We gratefully acknowledge the VSOP Project, which is led by the Japanese Institute of Space and Astronautical Science in cooperation with many organizations and radio telescopes around the world. This research was performed in part at the Jet Propulsion Laboratory, California Institute of Technology, under contract to NASA.
Preston, R. A.↗
Global Positioning System Time Transfer Receiver (GPS/TTR) prototype design and initial test evaluation
Time transfer equipment and techniques used with the Navigation Technology Satellites were modified and extended for use with the Global Positioning System (GPS) satellites. A prototype receiver was built and field tested. The receiver uses the GPS L1 link at 1575 MHz with C/A code only to resolve a measured range to the satellite. A theoretical range is computed from the satellite ephemeris transmitted in the data message and the user's coordinates. Results of user offset from GPS time are obtained by differencing the measured and theoretical ranges and applying calibration corrections. Results of the first field test evaluation of the receiver are presented.
Oaks, J.↗