Invited Presentation

Operations, scheduling and Imaging of VSOP experiments

Author(s): Edward Fomalont (NRAO/ALMA)

Presenter: Edward Fomalont (NRAO/ALMA)

Approximately twenty-five percent of the VSOP mission time was dedicated to the VSOP Survey Program. The source list was the 294 brightest, compact AGN in the sky. As with the VSOP mission in general, resources in many countries (antennas, correlators, data analysts) combined efforts to observe and image the sources over the seven year.The poster background is formed from the 234 images in the VSOP Survey.

Observations: Each observation contained the HALCA satellite with a minimum of three ground radio antennas with an observation time of four to six hours at 5GHz [1]. The figure shows the contributions from the ground antennas
and the final status of the observations. Paper III and V [2] are plotted in different colours.

Imaging: Of the potential 294 targets selected in the pre-launch survey [3], 265 sources were observed and 92% were found to have a detectable compact core. Of these 234 sources could be imaged and deconvolved.

Results: The image resolution was about 50 mas and many showed a strong core, often plus a fainter jet and/or secondary structure. Over half of the sources have a component with a brightness temperature >10**12K, with maximum of 3x10^13K[4]. Some correlation was found between radio compactness and extreme total intensity variability and Interstellar Scintillation [5].

Conclusions: The VSOP Survey program formed the legacy survey from the space mission, and both the database and the catalogues are regularly drawn upon as reference points in other space missions and VLBI observations.

References: [1] Hirabayashi etal, 2000, P-I: Observations
[2] Scott etal, 2004 & Dodson etal, 2008, P-III & P-V:
[3] Fomalont etal, Pre-launch Survey
[4] Horiuchi etal, 2004, P-IV: Size/Tb dist
[5] Jauncey etal, 2003, Variability