The Square Kilometre Array Radio Telescope is the next generation radio telescope. An international project is currently under way to design and build an instrument having an effective collecting area two orders of magnitude greater than that of any existing telescope. A number of separate studies are presently investigating how to design the Square Kilometre Array to best carry out the kinds of observations desired by the astronomical community. We present a summary of one of these studies, a workshop called The ‘Sub-microJansky Radio Sky’ held at the ATNF, Sydney, on 17 June 1998. This workshop addressed the nature of the radio sky at the very faint flux densities likely to be attainable by the Square Kilometre Array. In particular, each speaker investigated a separate population of radio sources and how the expected appearance of that population at such faint flux densities would dictate how to refine some of the design constraints for the Square Kilometre Array.

We report a search for the NH3 (J,K) = (1,1) inversion line in the Large Magellanic Cloud (LMC) using the Parkes 64–m telescope. Candidate positions were chosen with the help of recent H i data from the Australia Telescope Compact Array and published 12CO data from the Swedish–ESO Submillimetre Telescope. No detections of NH3 in emission were found at the positions surveyed. Upper limits are approximately 25 to 74 mK.

Using stellar population synthesis techniques, we explore the photometric signatures of white dwarf progenitor dominated galactic halos, in order to constrain the fraction of halo mass that may be locked up in white dwarf stellar remnants. We first construct a 109 M⊙ stellar halo using the canonical Salpeter initial stellar mass distribution, and then allow for an additional component of low- and intermediate-mass stars, which ultimately give rise to white dwarf remnants. Microlensing observations towards the Large Magellanic Cloud, coupled with several ground-based proper motion surveys, have led to claims that in excess of 20% of the dynamical mass of the halo (1012 M⊙) might be found in white dwarfs. Our results indicate that (1) even if only 1% of the dynamical mass of the dark halo today could be attributed to white dwarfs, their main sequence progenitors at high redshift (z ≈ 3) would have resulted in halos more than 100 times more luminous than those expected from conventional initial mass functions alone, and (2) any putative halo white dwarf progenitor dominated initial mass function component, regardless of its dynamical importance, would be virtually impossible to detect at the present day, due to its extremely faint surface brightness.

The most recent helium abundance determinations in main sequence B stars are those of Hardrop and Scholtz, Kodaira and Scholtz, Norris, and Leckrone. Their results indicate that it is possible to assign a helium abundance which is characteristic of all B stars. Norris and Leckrone worked with a number of B stars ranging from B0 to B9, and both have assigned a characteristic helium abundance to the B stars. Norris derived a value, A = 0.088 ± 0.012, and Leckrone a value of A = 0.106 ± 0.01, where A is the abundance of helium relative to hydrogen by number.

The primary function of the 64-m telescope, situated at Tidbinbilla near Canberra, is to communicate with and to control NASA’s unmanned interplanetary space craft (Reid et al. 1973). Similar telescopes are situated at Goldstone in California and in Madrid and are part of the NASA-JPL Deep Space Network (DSN). Under the Host Country Radio Science Agreement between the U.S. and Australia the telescope is available to Australian astronomers at times outside those committed to normal tracking. A radiometer operating at λ = 13.5 mm has been built by CSIRO for use on the 64-m telescope. It was initially used for VLBI observations of water vapour masers on baselines between the U.S., Australia and USSR (Batchelor et al. 1976).

In theories of the heating of the solar corona a number of authors have recently considered the propagation and damping of fast and slow magnetohydrodynamic waves, in the form of surface waves localized on the interfaces of coronal flux tubes (Ionson 1978, Wentzel 1979, Roberts 1981, Cramer and Donnelly 1983). The damping of these waves occurs, in addition to a rather weak global damping due to viscous or resistive dissipation, by means of a localized absorption at a so-called ‘resonance’ in the density or magnetic field profile forming the flux tube. At such a resonance, the wave frequency is equal to the local value of the Alfven wave frequency, in the case of Alfven resonance absorption, or at the local slow mhd wave frequency, in the case of the ‘cusp’ or ‘compressive singularity’ resonance in a finite pressure plasma.

Historically, infrared instrumentation for astronomical research has been developed by individual groups largely for their own enjoyment. The commissioning of the AAO’s infrared photometer-spectrometer (IRPS) in late 1978 provided for the first time in Australia a common-user instrument. Since then it has attracted considerable interest and is now the second most popular instrument in use at the AAT.

Dissipation of shock waves has often been proposed as the energy source required to sustain the outward temperature rise in the solar atmosphere. Theoretical models for the heating process have been developed by equating the mechanical energy input to the radiative energy loss at each height, but neither of these processes is well understood, and the lack of data means that the models are necessarily crude.

The University of NSW Automated Patrol Telescope (APT), a modified 0.5 m Baker-Nunn Schmidt telescope situated at Siding Spring Observatory, Coonabarabran, Australia, was opened in June 1989. It features the unique combination of an extremely fast (f/1) optical system with a CCD (Charge-Coupled Device) camera at the prime focus, capable of both fast (50 Hz TV-rate) imaging and slow-scan integrated readout via a low noise Correlated Double Sampling amplifier. This combination of optics and detector gives a wide field (0.9° × 1.4°) suited to observing extended objects including the LMC, SMC and galaxies in the Sculptor group. First images from the APT are presented along with the results of noise, linearity and dark current measurements made to date with a 12-bit analog-to-digital converter. Results were (ADU = Analog-Digital Unit):

The Sloan Digital Sky Survey has been immensely successful in detecting new Milky Way satellite galaxies over the past seven years. It was instrumental in finding examples of the least luminous galaxies we know in the Universe, uncovering apparent inconsistencies between cold dark matter theory and dwarf galaxy properties, providing first evidence for a possible lower mass limit for dark matter halos in visible galaxies, and reopening the discussion about the building block scenario for the Milky Way halo. Nonetheless, these results are still drawn only from a relatively small number of galaxies distributed over an area covering about 29% of the sky, which leaves us currently with more questions than answers. The study of these extreme stellar systems is a multi-parameter problem: ages, metallicities, star formation histories, dark matter contents, population fractions and spatial distributions must be determined. Progress in the field is discussed and attention drawn to some of the limitations that currently hamper our ability to fully understand the phenomenon of the ‘ultra-faint dwarf galaxy’. In this context, the Stromlo Milky Way Satellite Survey represents a new initiative to systematically search and scrutinize optically elusive Milky Way satellite galaxies in the Southern hemisphere. In doing so, the program aims at investigating some of the challenging questions in stellar evolution, galaxy formation and near-field cosmology.

In conjunction with the Australian Government's Spectrum Management Agency, experimental tests have been carried out to determine the susceptibility of the Molonglo Observatory Synthesis Telescope (MOST) to interference from terrestrial transmitters. The motivation for the tests was to reconcile the conflicting requirements of the MOST, which is committed to an extensive survey of the southern sky at 843 MHz, with the commercial use of the 825–845 MHz band, which is being prepared for sale. The tests show that the far sidelobe gain of the MOST, relative to an isotropic antenna is generally less than 1, and that an appropriate interference criterion would be that in-band interference irradiance should not exceed −173 dBWm−2. This value is similar to that considered by the International Telecommunications Union to be detrimental to radio astronomy continuum observations at nearby frequencies.

We describe a major Anglo-Australian project to undertake a UKST Ha survey of the Southern Galactic plane, Magellanic clouds and selected regions. The survey will use a new 12 × 12 inch monolithic Hα interference filter of high specification and Tech Pan film which offers significant advantages over other emulsions due to its peak sensitivity at Ha and its extremely fine grain, high resolution, exceptional DQE, excellent imaging and low noise. A survey of unprecedented area coverage, depth and resolution should result, superior to any previous optical survey of ionised gas in the galaxy. It is certain to lead to exciting new discoveries and new avenues of research.

The 16-inch telescope on Canopus Hill (Tasmania) has been equipped with a Coudé spectrograph.

The concept of a national centre for the analysis of archival and contemporary space astronomy data has been identified as a highly desirable objective by the Australian astronomical community for a number of years. With the approaching launch of the Hubble Space Telescope (HST), the time is now appropriate to actively pursue this objective. HST will generate a data archive of unique astrophysical significance over the course of the ≥ 20 year mission. It is essential that Australian astronomers have efficient access to this resource, both to maintain our position at the forefront of astronomical research, and to complement our major ground-based facilities (particularly the AAT and the Australia Telescope). An Australian facility would provide efficient access to HST data and also to the analysis tools and expertise necessary for utilizing the data. Archival data from other NASA and ESA missions could also be supported, and in the longer term, the facility could become the science centre for the Lyman/Quasat missions.

This paper presents the case for an Australian Space Astronomy Data Centre, reviews the astronomy missions of relevance, and addresses the role, scope and implementation timescale of the facility. Preliminary estimates are given for the resources that will be required, and possible routes for funding the centre are outlined. Above all, the report is intended as a Discussion Paper to promote further consideration of the concept and of the service that could be provided to the Australian astronomical community.

Combining our own observations with data from the literature, we consider the incidence of HI absorption in gigahertz peaked spectrum (GPS) and compact steep spectrum (CSS) sources. Here we present our preliminary results, where we find that the smaller GPS sources (<1 kpc) on average have larger HI column densities than the larger CSS sources (>1 kpc). Both a spherical and an axi-symmetric gas distribution, with a radial power law density profile, can be used to explain this anti-correlation between projected linear size and HI column density. Since most detections occur in galaxy classified objects, we argue that if the unified schemes apply to the GPS/CSS sources, a disk distribution for the HI is more likely.

We study the contents of an apparent void in the distribution of Lyα emitting galaxies at redshift 2.38. We show that this void is not empty, but contains a damped Lyα absorption-line system, seen in absorption against background QSO 2138-4427. Imaging does not reveal any galaxy associated with this absorption-line system, but it contains metals (Fe/H ∼ −1.3), and its large velocity range (∼180 km s−1) implies a significant mass.

This conference has shown that the accumulated wealth of data on SN 1987A has enabled us to learn an unprecedented amount of physical information about a single supernova event and supernovae in general, as well as to confirm much of the heretofore established theory. While some difficult problems remain, I discuss some particularly simple and useful theoretical notions concerning the bolometric and γ-ray light curves which can be gleaned from our current body of knowledge, drawing primarily upon results of analytic work performed by W.D. Arnett and myself. Also, the work of Lamb, Melia and Loredo (1987) on neutrinos from the supernova is discussed briefly.

In 1994, the New South Wales Board of Studies, Australia, introduced three high level Distinction Courses for gifted and talented students: Comparative Literature, Cosmology, and Philosophy. All are offered by distance education but the cosmology course employs an interactive design model and an extensive communication system that differentiates it from the other two. This paper explains the model and the way it is used in practice to organise, sequence and deliver the course. A discussion addresses ways in which the model might be used to design a wider range of courses in science for gifted and talented students.

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.

Practical astronomy is usually taught using optical telescopes or, more rarely, radio telescopes. For a similar cost, complementary studies may be made of astrophysical particles through the use of a modestly sized muon detector. Such a detector records the arrival of cosmic ray particles that have traversed the heliosphere and the rate of muon detections reflects the flux of those particles. That flux is controlled by the day to day properties of the heliosphere which is in a state of constant change as the outflowing solar wind is affected by solar activity. As a consequence, a laboratory muon detector, whose count rate depends on the state of the heliosphere, can be an interesting and useful teaching tool that is complementary to optical or radio studies of the Sun.