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The VSOP Survey Working Group meeting was held at the Institute of Space and Astronautical Science on the 5th and 6th September. The meeting was attended by just over forty people, sixteen of whom had come from overseas for the meeting. Expressions of interest in the Survey Working Group (SWG) were received from a further nine people or groups who were unable to attend the meeting.
H. Hirosawa, VSOP Project Manager, opened the meeting by welcoming all participants. He emphasized the importance of the Survey Program to the mission, and encouraged participation of SWG members in VSOP operations. Hirosawa-san also gave a short summary of recent progress with the mission, and showed photographs of main antenna deployment tests and M-V rocket tests.
An overview of the Survey Program as outlined in the Announcement of Opportunity was then given by H. Hirabayashi (ISAS). This was followed by presentations of more specific considerations for the Survey Program by M. Inoue (NAO) and R. Preston (JPL).
A number of presentations were then given regarding ideas and comments on continuum extragalactic surveys. R. Linfield (JPL), D. Murphy (JPL) and J. Ulvestad (JPL) spoke on various aspects of the survey from the perspective of TDRSS experiment results and simulations. A series of presentations were then given with specific ideas and comments by K. Fujisawa (ISAS), E. Fomalont (NRAO), L. Gurvits (JIVE), S. Kameno (NAO), N. Kawaguchi (NAO), R. Linfield (JPL), C. Lonsdale (Haystack), P. McCulloch (Tasmania), D. Shaffer (Radiometrics) and E. Valtaoja (Metsahovi).
Discussion points included: What should the main survey frequency be? and should observations at other frequencies be included? Should repeated observations be made of any sources? How many orbits per source? How many telescopes per observation? Could information from monitoring programs be usefully incorporated in scheduling SWG observations? How much can incoherent averaging and the vector triple product "win back" for the lower 22GHz sensitivity?
In the afternoon H. Kobayashi (ISAS) and V. Migenes (NAO) introduced the maser survey session with comments on the feasibilities and limitations for the surveys, and a report on the progress with pre-launch survey of maser sources. K. Shibata (NAO), P. McCulloch (Tasmania) and V. Migenes (NAO) then gave talks on specific ideas for maser surveys. Discussion points included: What limitation would time-average smearing impose on the field of view? How much multiple-field correlating or mosaicing would be required? What should be the distribution between masers associated with low-mass proto-stars, massive star-forming regions, and evolved stars? Should proper motion studies be attempted when they could in fact be done better from ground-based observations? Are there possibilities for polarimetry observations of maser sources?
The second day started with presentations on the various resources required, or contributed to, the Survey Program. H. Hirabayashi (ISAS), P. Edwards (ISAS), J. Ulvestad (JPL), D. Meier (JPL), C. Flatters (NRAO) spoke on various aspects of the resources required and contributed (including those offered by those unable to attend the meeting). P. McCulloch (Tasmania), T. Iwata (CRL), L. Gurvits (JIVE), E. Fomalont (NRAO), J. Ulvestad (JPL), K. Lepannen (Metsahovi) and C. Lonsdale (Haystack) then gave short presentations on the possible use of specific telescopes and other resources.
Discussion included: S2 recorders and formatters in tracking stations and selected telescopes and the the use of the Canadian S2 correlator; the possible limitations imposed by finite VSOP and VLBA tape supplies; scheduling implications of the Survey Program; the potential availability to the Survey Program of other resources through application by the SWG for the use of these facilities.
The afternoon session was spent discussing the various survey plans. The consensus at the end of the meeting produced a strawman plan with three principal scientific goals:
Working groups have been set up to determine the SWG source lists. It is anticipated that these will be ready to be made available to the astronomical community by early October.
The mission favoured a "flat-spectrum" SWG membership, with all those attending the meeting or submitting expressions of interest becoming SWG members. The rewards of SWG membership would naturally go to those contributing to the Survey Program, and all members will be contacted individually to ascertain how they can contribute to the Survey Program.
SWG management was debated, and ideas fleshed out in discussions the following day. H. Hirabayashi will lead the SWG, with M. Inoue being the SWG co-ordinator. Five main areas were then defined:
People to head these areas will be assigned shortly.
Any part of the operations that is not unique to the surveys was assumed to fall under the general VSOP organization so as not to create duplicate structures. SWG activities will be monitored by the VISC.