Space VLBI observations of southern hemisphere gamma-ray and non-gamma-ray AGN: First results for PKS 0637-752

• Published in: Advances in space research 2000-01, Vol.26 (4), p.677-680
• Main Authors: Tingay, S.J., Jauncey, D.L., Reynolds, J.E., Tzioumis, A.K., King, E.A., Preston, R.A., Murphy, D.W., Meier, D.L., Edwards, P.G., Lovell, J.E.J., Hirabayashi, H., Kobayashi, H., Shibata, K.M., McCulloch, P.M., Costa, M.E., Dewdney, P., Cannon, W., Nicolson, G., Valtaoja, E., Tornikoski, M., Venturi, T.
• Format: Article
• Language: English
• ISSN: 0273-1177; 1879-1948
• DOI: 10.1016/S0273-1177(99)01189-8

We present the first results from our VSOP proposal, “γ-ray loud and quiet AGN with VSOP and SHEVE at 5 GHz”. This project is aimed at determining what, if anything, differentiates γ-ray-identified radio sources from similar strong, flat-spectrum radio sources which have not been identified as sources of greater than 100 MeV γ-rays. Five VSOP observations have been successfully completed as part of this project during VSOP AO1. One observation has been correlated thus far, a 4.970 GHz observation of PKS 0637-752 from 1997 November 21. We present the VSOP image for PKS 0637-752 and make comparisons between the space VLBI image and ground-based VLBI and Australia Telescope Compact Array (ATCA) images, as well as present ATCA flux density monitoring at 4.8 GHz. A brightness temperature for PKS 0637-752 of 0.7 × 10 12 K has been determined from the VSOP data and a tentative apparent superluminal speed, from comparison to the ground-based VLBI image, of ∼9c.