VSOP Survey Images
Because the maximum distance between Halca and ground
radio telescopes is much greater than can be achieved with
ground radio telescopes alone, the resolution of images made with
survey data is typically two to three times better than images
made with ground-based VLBI.
Images of survey sources can be constructed when the number of
co-observing ground telescopes exceeds a minimum number (two
or three, depending on the quality of the a-priori telescope
gain and system temperature information).
High resolution imaging
of the AGN cores is crucial to understanding the nature of
the emission mechanism "powering" these AGN.
Using Halca, images of AGN cores
with sub-mas resolution can be constructed. For relatively nearby
AGN ( Z < 1), this corresponds to a linear distance on the order
Four images of VSOP survey sources that were at least partially resolved
out are shown above. The resolution of
the images in all four cases in roughly 1.0 mas X 0.3 mas.
The sources on the upper left and right are QSOs, while the lower left source
is a BL-Lac, and the lower right source is a radio-galaxy.
Redshifts for these sources range from 0.35
Overlayed on these images are contours made by subtracting
the data from the Space-ground baselines.
In all cases, the resolution is considerably reduced.
For the lower right source, when Halca was subtracted from the array,
the remaining three ground radio telescopes (Hobart and Mopra in
Australia, and Hartebeesthoek in South Africa) formed nearly an East-West
array. This resulted in the exceptionally bad resolution seen in the
Additional space VLBI images from general observing time proposals can
be found on the ISAS
to the University of Calgary Space VLBI Web Page.
Comments and inquiries to:
Russ Taylor: (firstname.lastname@example.org)
Bill Scott: (bill at ras.ucalgary.ca)