Arcsecond Scales Research Articles

5-GHz observations of cores in extended radio galaxies

Results are presented from a search for radio cores at 5 GHz with the VLA in 18 moderately luminous radio galaxies from the second Bologna catalogue. Maps of several of the ten detected cores indicate structure on arcsecond scales in addition to the unresolved central source. Higher-resolution, multifrequency observations are very desirable in future studies of such cores. A statistical study of these and previously observed samples of radio galaxies was then performed. It was found that the radio core luminosity is much stronger in galaxies that are optically bright than faint, and that strong cores tend to occur only in galaxies with luminous extended sources while weak cores can occur in all ranges of extended source luminosity.

Intermediate Scale Structure

What does intermediate (arcsecond) scale structure tell us about the activity deep in the VLBI cores of galaxies and quasars? There are certain key areas where a knowledge of this structure is particularly relevant. One is in defining the relationships between the various classes of objects leading to unified schemes. A second is in the understanding of jet physics. For the latter it is very important to know if the material in the jets supplied from the nucleus is heavy or light, slow or fast, ejected one side at a time or symmetrically. The optimum resolution to study jet material is on the arcsecond (≡ kiloparsec) scale where very high dynamic range maps are possible and where it becomes feasible to find out something about the physical conditions in the surrounding medium from optical and X-ray observations.

A complex picture of 3C 345

view Abstract Citations (20) References (10) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS A complex picture of 3C 345 Spencer, J. H. ; Johnston, K. J. ; Pauliny-Toth, I. I. K. ; Witzel, A. Abstract 1980.1 epoch VLBI observations are presented at 5011 MHz of 3C 345 which show it to have complex structure on the milliarcsecond scale, indicating that it is not a simple double source. This complex source structure appears to cloud the interpretation of superluminal expansion in this source. The structure appears to be consistent with a model of a bent beam that extends to the arcsecond scale structure. Publication: The Astrophysical Journal Pub Date: December 1981 DOI: 10.1086/183694 Bibcode: 1981ApJ...251L..61S Keywords: Astronomical Maps; Quasars; Very Long Base Interferometry; Astronomical Models; Radio Astronomy; Radio Sources (Astronomy); Visibility; Astronomy full text sources ADS | data products NED (2)