DOI:
10.1016/S1387-6473(99)00060-3
Authors:
Rioja, M. J.;Porcas, R. W.;Garrington, S.;Alberdi, A.;Saikia, D. J.
Abstract:
We present maps and astrometric results from first epoch, simultaneous MERLIN and Global VLBI observations of the very weak core of a double-lobed radio source, using as reference the bright, compact, flat-spectrum quasar 1636+473 A, 20 arcsec away. The observations were made in May 1995 at 5 GHz. The phase-referenced VLBI map of the weak core, of resolution 1.5 mas, contains a high percentage of the core flux density seen in the MERLIN map. Further hybrid mapping iterations reveal a faint, one-sided core extension on the same side as the MERLIN jet. We explore the effect of both temporal and other coherence losses on the phase-reference map. We relate our results to the structural asymmetry in weak AGN cores within the context of unification models.
URL:
https://ui.adsabs.harvard.edu/#abs/1999NewAR..43..593R/abstract