EVOLUTION OF THE PARSEC-SCALE STRUCTURE OF PKS 1934-638 REVISITED: FIRST SCIENCE WITH THE ASKAP AND NEW ZEALAND TELESCOPES
- CSIRO Astronomy and Space Science P.O. Box 76, Epping, NSW 1710 (Australia)
- International Centre for Radio Astronomy Research, Curtin University of Technology GPO Box U1987, Perth, Western Australia 6102 (Australia)
- Institute for Radio Astronomy and Space Research, Auckland University of Technology, Private Bag 92006, Auckland 1142 (New Zealand)
We have studied the archetypal Gigahertz Peaked Spectrum radio galaxy, PKS 1934 - 638, using the Australian Long Baseline Array augmented with two new telescopes that greatly improve the angular resolution of the array. These very long baseline interferometry observations represent the first scientific results from a new antenna in New Zealand and the first antenna of the Australian SKA Pathfinder. A compact double radio source, PKS 1934 - 638 has been monitored over a period of 40 years and the observation described here provides the latest datum, eight years after the previous observation, to aid in the study of the long-term evolution of the source structure. We take advantage of these new long baselines to probe PKS 1934 - 638 at the relatively low frequency of 1.4 GHz in order to examine the effects of optical depth on the structure of the radio source. Optical depth effects, resulting in the observation of frequency-dependent structure, may have previously been interpreted in terms of an expansion of the source as a function of time. Expansion and frequency-dependent effects are important to disentangle in order to estimate the age of PKS 1934 - 638. We show that frequency-dependent structure effects are likely to be important in PKS 1934 - 638 and present a simple two-dimensional synchrotron source model in which opacity effects due to synchrotron self-absorption are taken into account. Evidence for expansion of the radio source over 40 years is therefore weak with consequences for the estimated age of the radio source.
- OSTI ID:
- 21443184
- Journal Information:
- Astronomical Journal (New York, N.Y. Online), Vol. 140, Issue 5; Other Information: DOI: 10.1088/0004-6256/140/5/1506; ISSN 1538-3881
- Country of Publication:
- United States
- Language:
- English
Similar Records
The Two Sided Parsec Scale Structure of the Low Luminosity Active Galactic Nucleus in NGC 4278
The Two–sided Parsec–Scale Structure of the Low–Luminosity Active Galactic Nucleus in NGC 4278
Related Subjects
COSMOLOGY AND ASTRONOMY
ANTENNAS
EXPANSION
FREQUENCY DEPENDENCE
GALACTIC EVOLUTION
INTERFEROMETRY
RADIO GALAXIES
RESOLUTION
SELF-ABSORPTION
SYNCHROTRON RADIATION SOURCES
TELESCOPES
TIME DEPENDENCE
TWO-DIMENSIONAL CALCULATIONS
ABSORPTION
COSMIC RADIO SOURCES
ELECTRICAL EQUIPMENT
EQUIPMENT
EVOLUTION
GALAXIES
RADIATION SOURCES
SORPTION