A new survey of the southern sky for pulsars is being carried out jointly by the University of Sydney and the CSIRO Division of Radiophysics. J. M. Durdin, M. I. Large and A. G. Little from Sydney University have been working with R. N. Manchester, J. H. Taylor and myself from Radiophysics. This paper provides a brief description of the experiment and an account of progress to date.

We present observations of Hα and CaII resonance lines in 4 stars having Hα features which place them intermediately between the non-(e) and (e) classifications of dK/dM stars. There is considerable variety in the shape of the Hα line, presumably due in part to differences in rotation rates. As expected, the energy fluxes in the CaII emission lines lie between those typical of non-(e) and (e) stars. There is some evidence (especially from the binary Gl 876A) that the energy fluxes in the CaII and Hα emission lines do not vary from star to star according to a simple proportionality. An intriguing result is the apparent detection of spatially displaced chromospheric emission in Gl 907.1 and Gl 890.

The term ‘flare continuum’ (denoted by FC) was introduced by Wild (1970) to describe a strong, stationary continuum source at the metre wavelengths which occurs early in some flare events, particularly those of high energy. The flare continuum is distinct from the ‘storm continuum’ (SC), which occurs late in some flare events, becomes strongly circularly polarized and may continue as a ‘storm’. Both had previously been referred to as ‘stationary type IV’ bursts, to distinguish them from the original ‘moving type IV’ burst, IVM.

The most extensive studies of supernova remnants (SNRs) in the past have taken place at radio and optical wavelengths.

Recent two-dimensional observations of the quiet sun at 80 MHz by Sheridan showed a persistent low-intensity source (radio enhancement) whose daily motion was consistent with a source at radius 0.95 R® rotating with a synodic period of 27.3 d. In this paper we shall attempt to interpret this result in terms of the effects of refraction and opacity in model coronas. Comprehensive studies of the Sun at 169 MHz show that similar radio enhancements are associated with coronal streamers and that reasonable values for electron density and temperature within the coronal streamer allow the observations to be explained in terms of thermal radiation. Hence we shall consider only coronal models that possess streamer structure. We shall show that temperature enhancements within the streamer (‘thermal model’) do not lead to an apparent radius as small as that observed by Sheridan and that his observation may be better understood in terms of a non-thermal model for radiation from the streamer region.

Cas A has a radio surface brightness much higher (by a factor of about 100) than that of any other galactic supernova remnant (SNR) and is probably the youngest (≤ 300 yr). It therefore provides unique information on young remnants, but this very uniqueness makes it hazardous to treat Cas A as a typical remnant. However, because it (i) shows a clearly defined shell of radio emission of much the same type as older remnants, and (ii) lies approximately on the extrapolation of the Σ.-D (surface brightness-diameter) relationship derived for older remnants (Clark and Caswell 1976); Caswell and Lerche 1979a), detailed comparison with older remnants seems appropriate.

For many years now, large plastic scintillator and geiger counter muon telescope systems have been used underground for studies of the small variations of the cosmic ray particle intensity that occur at primary energies around 1011 – 1012 eV. Although long-term deterioration in telescope counting efficiency is liable to take place it has been possible to take care of it sufficiently well to allow accurate observations to be made of the important daily variation and of transient events such as the Forbush Decrease and the solar flare increase.

Of the attempts to model the Magellanic system as the result of tidal interactions, only the works of Lin and Lynden-Bell (LLB 1982) and Murai and Fujimoto (MF 1981) can be considered to be successful.

Despite its superb optical and radio observatories, Australia is essentially blind to the entire submillimeter and far-infrared spectrum. The importance of this spectral region can perhaps best be illustrated by reference to Figure 1, which shows the flux of the galaxy NGC253 as a function of frequency.

A consortium of Australian universities and the Anglo-Australian Observatory is currently implementing an adaptive optical system at the Anglo-Australian Telescope. This project aims to enhance the science output of the telescope and establish the utility of adaptive optics at the AAT site. The first stage of the project is a fast tip-tilt system, described here, to be installed in the west coudé room. Subsequent funding has been obtained to implement a second-stage, low-order deformable mirror system which is also outlined. Both phases will primarily serve the IRIS camera/spectrograph, since the maximum gains in image quality will occur in the infrared.

In the wide complex profiles of OH, H2CO and CO spectra observed in directions towards the galactic centre, only the features at radial velocities near + 40 km s-1 are generally believed to originate in the molecular clouds nearest the galactic nucleus. The features at other velocities are associated with clouds or spiral features that can be traced over larger ranges of galactic longitude, implying locations which are more distant from the nucleus. In particular, the features near zero velocity have been traditionally associated with molecular clouds within 1-2 kpc of the Sun. However, H2CO observations with high velocity resolution provide evidence that one cloud with velocity near zero is probably near the galactic nucleus.

Work is in progress on the extension of a detailed stellar structure code to explore a suggested solution to the Solar Neutrino Problem where the Sun has a small (∼0.01M⊙) high-Z core on entry to the ZAMS. A basic premise of such models is that the core will burn itself out by solar age and the model acquire a neutrino luminosity in line with that observed. The work to date has involved the construction of a standard solar model and, currently, the development of inhomogeneous models with associated adjustments to the structure equations.

On 1973 March 22 a radio event was observed above the east limb of the Sun with the Culgoora radioheliograph operating at both 80 and 160 MHz. The first stage of this event, a type I storm closely associated with a rising prominence, offers a new insight into the nature of this phenomenon. This storm was followed immediately by a moving type IV burst – the first burst of this kind for which two-dimensional observations are available at two frequencies. The relation between these two stages may help explain the ‘missing hour’ in observations of another moving type IV burst known as ‘Westward Ho’.

The darkness of sunspots has been attributed by many authors (Biermann 1941; Danielson 1961) to the inhibition of the normal solar convective processes by the presence of strong magnetic fields. Observations of the solar photospheric granulation pattern have also shown that a weak longitudinal field exists outside the activity regions. Although these observations have not revealed any close association between the magnetic field and individual granules, nor the exact reasons for the darker cell boundaries, it must be accepted that, overall, the role of the magnetic field must be such as to influence the cell structure and reduce the normal heat transfer by convection.

A combined multi-station radar equipment of c.w. and pulse at 27 MHz was used at Adelaide (lat. 35°S) during the period December 1968 to June 1969 and again in October 1969 to measure radiants and velocities of individual meteors down to limiting radio magnitude MR = + 8. Reflections from 3 to 5 points typically separated by 2 to 6 km along each trail were used and corrections for the effects of meteor region winds and wind shears were included. To date 1667 orbits have been determined from 6 months of data.

In an attempt to determine whether the lithium Une at 6707 Å cornes mainly from the quiet photosphere or from the cooler spots on spotted active stars we have measured Une équivalent widths due to Li and also due to Cal at 6717 Å at various rotation phases on three fast rotating stars, AB Doradus, PZ Telescopium and V 1005 Orionis. The results for AB Dor and PZ Tel show there might be some small rotational modulation which can be linked to the best estimate of the spot position from the available photometry. This moduation is less than that expected on the basis of Giampapa’s work on sunspot spectra. The Li and Cal line equivalent widths were found to anticorrelate.

We present near-infrared images and spectra of the peculiar radio galaxy Centaurus A. The images reveal extended emission regions at the longer wavelengths and show colours characteristic of reddened starlight. We believe we are seeing stars within the warped disc of Cen A, which are obscured in the optical by dust. Both images and spectra indicate the presence of a compact core, whose colours are much redder than those of the surrounding stars. In the spectrum of the core, detections have been made of [Fe II] 1.644 μm, H2 2.122 μm and Br γ. These lines appear to peak on the nucleus and their presence and width suggest starburst activity.

Most plates taken with the UK Schmidt Telescope are hypersensitized before use. The technique for the hyper-sensitization of IIIa-type emulsions has been described by Sim et al. (1976), and for the IV-N emulsion by Hartley and Tritton (1979). Photographic calibration is provided by two sensitometers, a seven-step linear array at the N-W corner and a 4 × 4 spot array in the S-E. During the calibration of this latter sensitometer (Dawe and Metcalfe 1981), which is a copy of a design by Schoening (1976), it became apparent that the sensitivity of the hypersensitized IIIa-emulsions in use was decreasing as a function of time in the plateholder.

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.