VSOP: The VLBI Space Observatory Programme

The VSOP 5 GHz AGN Survey

In addition to the General Observing Time (which is open to the astronomical community, a separate Survey Program will also be undertaken.

The Survey Program will be led by the VSOP mission through the Survey Working Group (SWG). The SWG will define and carry out surveys of active galactic nuclei and maser sources to determine general characteristics of various classes of sources (e.g., brightness temperatures). The survey results will be essential for planning future VLBI observations (including those with VSOP) and for designing future space VLBI missions.

Few ground telescopes will be available for the survey observations. Thus, although the source structure information in such data will, of necessity, be limited, these periods provide an excellent opportunity to perform surveys by utilizing telescope time outside of the General Observing Time pool that would not be useful for more detailed imaging investigations.

The mission convened an open international SWG meeting at ISAS on the 5th and 6th of September 1995 to discuss the definition of the surveys to be undertaken. A summary of this meeting can be found here.

VSOP Survey Working Group Data Reduction Meeting (SWGM)

About 250 of the sources observed with the VLBA had correlated flux densities at least 0.3 Jy on the longest VLBA baseline and these sources are currently being observed with VSOP at 5 GHz. The results from the VLBA pre-launch observations (VLBApls): the color and contour display of the images, the correlated flux density dependence with u-v distance, and improved positions for 62 sources : are presented here.

A description of the AGN survey(including the survey source list) is available here. The VSOP Survey Program Source List is also available below:

Results from the Survey observations is available at links from this page as the analysis proceeds.

Released data.

VSOP Survey Publications

The VSOP Survey Database
Observation logs and analysis results of all survey experiments.


Points of Contact

2005 Sep 5
Jim Lovell