A new astronomical window into the southern skies has been opened with the high-frequency upgrade to the Australia Telescope Compact Array (ATCA), which allows radio-interferometric mapping of sources at wavelengths as short as 3 mm. In anticipation of the upgrade's completion, a two-day workshop was held at the University of Melbourne in November 2001. The workshop covered a diverse range of fields, tied together by a common theme of identifying key areas where ATCA observations can have an impact. More than half of the talks were concerned with molecular clouds and star formation, with the remainder covering topics such as molecular gas in the Galactic Centre, Seyfert nuclei, and high-redshift objects. Some early results from the 3 and 12 mm prototype systems were also presented. In consultation with the speakers, we are presenting in this article a summary of the talks. The original slides are available from the ATNF website.

We report very long baseline array (VLBA) observations at 2.3, 8.4, and 15.4 GHz towards nine gigahertz peaked spectrum (GPS) sources. One Seyfert 1 galaxy, one Seyfert 2 galaxy, three radio galaxies, and four quasars were included in our survey. We obtained spatial distributions of the free–free absorption (FFA) opacity with milliarcsecond resolution for all sources. It is found that type 1 (Seyfert 1 and quasars) and type 2 (Seyfert 2 and radio galaxies) sources showed different distributions of the FFA opacities. The type 1 sources tend to show more asymmetric opacity distributions towards a double lobe, while those of the type 2 sources are rather symmetric. Our results imply that the different viewing angle of the jet causes the difference of FFA opacity along the external absorber. This idea supports the unified scheme between quasars and radio galaxies, proposed by Barthel (1989).

We present photometric observations of six radio-loud quasars that were detected by the COMPTEL gamma-ray telescope. The data encompass seven wavebands in the optical and near infrared. After correction for Galactic extinction, we find a wide range in optical slopes. Two sources are as blue as optically-selected quasars, and are likely to be dominated by the accretion disc emission, while three others show colours consistent with a red synchrotron component. We discuss the properties of the COMPTEL sample of quasars, as well as the implications our observations have for multiwavelength modelling of gamma-ray quasars.

Hierarchical clustering represents the favoured paradigm for galaxy formation throughout the Universe; due to its proximity, the Magellanic system offers one of the few opportunities for astrophysicists to decompose the full six-dimensional phase-space history of a satellite in the midst of being cannibalised by its host galaxy. The availability of improved observational data for the Magellanic Stream and parallel advances in computational power has led us to revisit the canonical tidal model describing the disruption of the Small Magellanic Cloud and the consequent formation of the Stream. We suggest improvements to the tidal model in light of these recent advances.

Children who visited Auckland Observatory and Stardome Planetarium in 1998 were surveyed on their ideas about the Earth, the Moon and the Sun. Widespread misconceptions similar to those found in other studies were revealed, however the single teaching session had an impact on children's ideas comparable to that of much longer interventions. Several ideas not reported previously were expressed. For example, two children drew a figure eight orbit for the Earth; circling the Sun during the day, and the Moon at night. Only one child of the 67 surveyed proposed the notion of day and night being caused by the Sun orbiting the Earth. This is in contrast to many other studies. A drawing based pre-post survey proved to be a convenient and powerful tool for revealing changing patterns in children's thinking. The literature surveyed indicated levels of misconceptions about astronomy among teachers and other adults that were nearly as great as those of the children being taught. It would seem a strategic move to provide teachers with sufficient training if they are required to teach astronomy at every level, as has happened with the New Zealand science curriculum. A comparison between different question types suggests that multiple-choice questions may underestimate the knowledge of younger children by over 300% when compared with interview responses. A drawing based question in this study generated up to 41% more correct responses than a multiple-choice question on the same topic.

We present global VLBI and VLBA observations of the compact steep spectrum quasar B1524–136. These observations reveal well-defined radio jets on both sides of the active nucleus. Also, the overall radio structure appears highly distorted and asymmetric with the counter-jet exhibiting several oscillations. A possible scenario is one in which jet and counter-jet are inclined at about 25° and 75° to the line of sight respectively and an environment which is dense on the jet side. Possible implications of these results are discussed.

Solar flares are thought to be caused by reconnection of magnetic fields and their associated electric currents in the solar corona. The currents have to be there to provide available energy over and above the current-free minimum energy state, but what generates them has been little discussed. This paper investigates the idea that twisting motions in the turbulent convection zone below may provide a natural source for the currents and explain some of their properties. The twists generate upward-propagating Alfvén waves with a Poynting flux of the right order of magnitude to power a flare. Depending on the depth it takes place, the twisting event that initiates a particular flare may occur hours, days or even months before the flare itself.

In the regions of highest optical obscuration and infrared confusion, only 21-cm emission can be used to find galaxies in the Zone of Avoidance. A feasibility study conducted with the 300-ft telescope successfully uncovered galaxies which seem to be consistent with populations of optically-selected low surface brightness galaxies. A complete survey is currently being conducted in the north with the Dwingeloo telescope. The big breakthrough should come in the south, however, with the advent of the Parkes telescope multibeam system.

We summarise results from flux density monitoring campaigns performed with the 100 m radio telescope at Effelsberg and the VLA during the past 15 yrs. We briefly discuss some of the statistical properties from now more than 40 high declination sources (δ ≥ 30°), which show intraday variability (IDV). In general, IDV is more pronounced for sources with flat radio spectra and compact VLBI structures. For 0917+62, we present new VLBI images which suggest that the variability pattern is modified by the occurrence of new jet components. For 0716+71, we show the first detection of IDV at millimetre wavelengths (32 GHz). For the physical interpretation of the IDV phenomenon, a complex source and frequency dependent superposition of interstellar scintillation and source intrinsic variability should be considered.

During the last decade multiwavelength observations of blazars have revealed many interesting patterns in their emission across the EM spectrum. In the present article we will review the time-dependent one-zone models and the models which advocate an acceleration and a radiation zone, and we will make some comparisons between them, especially in light of recent observations of the so-called TeV blazars.

The compact steep spectrum (CSS) and gigahertz peaked spectrum (GPS) sources are widely believed to be young radio sources, with ages ≤106 yr. If the activity in the nucleus is fuelled by the supply of gas, one might find evidence of this gas by studying the structural and polarisation characteristics of CSS sources and their evolution through this gas. In this paper we discuss some of the possible ‘smoking-gun’ evidence of this gas which may have triggered and fuelled the radio source.

Observational evidence indicating that the expansion of the universe is accelerating has surprised cosmologists in recent years. Cosmological models have sought to explain this acceleration by incorporating ‘dark energy’, of which the traditional cosmological constant is just one possible candidate. Several cosmological models involving an evolving equation of state of the dark energy have been proposed, as well as possible energy exchange to other components, such as dark matter. This paper summarizes the forms of the most prominent models and discusses their implications for cosmology and astrophysics. Finally, this paper examines the current and future observational constraints on the nature of dark energy.

The development of robotic telescopes for education is reviewed. The problems associated with providing a service for students at different levels of education are discussed. Consideration is made of the hardware requirements in the students' institution and the compromises that are made to allow the maximum number of students to use facilities. The demands on teachers are considered along with the available methods of delivering educational projects related to curricular demands at the various stages. The likely developments in the technology are considered and estimates made of the probable timescales. Proposals are made to optimise student access to observing facilities that would involve the development of a linux-like collaboration around astronomy software and the development of low cost telescope systems. Proposals are made to realise such systems with the objective of providing universal access for students with Internet access.

The anticorrelation between the turnover frequency in the radio spectrum and the projected linear size (indicative of the age in the currently favoured youth model) in powerful and intrinsically compact radio sources suggests that the youngest objects must have the highest turnover frequencies. We present preliminary results of new VLBA observations of a sample of sources peaking at frequencies higher than a few GHz, making them good candidates for being newly born sources. Our initial analysis deals with the morphological classification which allows us to study the contamination from beamed sources dominated by a single unresolved component.

Following the end of the Second World War, the CSIRO Radiophysics Laboratory applied the expertiseand surplus radar equipment acquired during the war to problems ofastronomy. Gordon Stanley was among the first group of scientists andengineers to work in the exciting new field of radio astronomy. Like many ofhis contemporaries, he had a strong background in radio and electronics butnone in astronomy. At the Radiophysics Laboratory, and later at Caltech,Stanley developed innovative new radio telescopes and sophisticatedinstrumentation which resulted in important new discoveries that changed, ina fundamental way, our understanding of the Universe. He was one of thosewho played a key role in the early development of radio astronomy both inAustralia and the United States.

The short-period (0d .34) close binary V508 Oph was observed in 2005 and four new times of minima were derived. All of the available times of minima, including the new ones, covering 69 years were analyzed. It was shown that the period change of the system is very complex. Two possible period oscillations with periods of 24.73 and 9.91 years and amplitudes of about 0.011 and 0.002 day, respectively, were found to superimpose on upward parabolic change, indicating a secular period increase at a rate of dp/dt = 4.24 × 10−9 days yr−1. The mechanisms that could explain the period changes of the system are discussed.

Recent history in South Africa has created unique problems in many areas. As a result of an unequal educational structure, particularly in science, there is a general lack of science literacy and awareness. Some years ago the South African Astronomical Observatory started a Science Education Initiative as a contribution to addressing this problem by using astronomy as a vehicle to stimulate an interest in science amongst teachers and students. This programme was given a boost by the South African government in 1998 and the construction of the Southern African Large Telescope will provide further stimulus to the Science Education Initiative.

The UKST/AAO Galactic Plane Hα Survey has the potential to discover many new objects not visible on red plates taken in past surveys. Recent radio surveys have identified large numbers of new supernova remnants, very few of which have been optically identified. Here we will discuss our plans to use this survey to search for optical emission from both new and known supernova remnants. Observations of these objects in the optical and radio wavelengths will reveal important information about the physical and chemical properties of supernova remnants, and their role in the evolution of the galaxy. We also present a composite image of a newly discovered Hα shell around the Coalsack, named the Coalsack Loop. This object has been detected in radio emission and may represent the remains of an old supernova remnant.