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.

We have used the Australia Telescope Compact Array to search for a number of centimetre wavelength methanol transitions which are predicted to show weak maser emission towards star formation regions. Sensitive, high spatial, and spectral resolution observations towards four high-mass star formation regions which show emission in a large number of class II methanol maser transitions did not result in any detections. From these observations, we are able to place an upper limit of ≲ 1300 K on the brightness temperature of any emission from the 31A+–31A−, 17−2–18−3 E (vt = 1), 124–133 A−, 124–133 A+, and 41A+–41A− transitions of methanol in these sources on angular scales of 2 arcsec. This upper limit is consistent with current models for class II methanol masers in high-mass star formation regions and better constraints than those provided here will likely require observations with next-generation radio telescopes.

The U.K. Schmidt telescope is one of three independent ‘observatories’ now on Siding Spring Mountain near Coonabarabran, and is operated by the United Kingdom Science Research Council. The telescope has been fully operational since September 1973. So far we have taken about 800 astronomical plates, about half being for the main IllaJ Survey and half for other scientific programmes. The latter have mostly been taken when the moon or mediocre seeing have prevented us working on the Survey.

The Parkes radio telescope has been used to search a list of small, dense southern dark clouds and Bok globules for ammonia emission at 23.7 GHz. The ammonia observations, together with IRAS data and the cloud’s visual appearance, have been used to determine a short list of dark clouds for observation with the infrared imaging system (IRIS) on the Anglo-Australian Telescope, in an attempt to determine the dust density distribution within the clouds. Near-infrared images of a number of the short listed clouds have been obtained with IRIS at J, H and K’. Preliminary results are reported for this ammonia survey, together with IRIS images of the strong ammonia source DC 297.7–2.8. Coincident with the dense ammonia core of this object is an IRAS ‘core’ source, IRAS 11590–6452 and an extremely interesting near-infrared source, which lies on the edge of the error ellipse of the IRAS source.

We present an analytic solution for a jet flow from a young stellar object (YSO). This solution allows us to compute the speed, density, and magnetic field strength of the flow, but it is only true if YSO jet flows are powered by toroidal magnetic fields. We illustrate how the balance between centrifugal force and magnetic pressure provides the converging/diverging nozzle shape required to accelerate the flow.

A method is presented that will enable the bivariate luminosity/surface brightness distribution of galaxies to be determined from a relatively small HI selected sample. This will be taken from the HI Parkes All Sky Survey (HIPASS). The advantages of using an HI sample in order to avoid the selection effects that are present at optical wavelengths are discussed. We are developing an algorithm to automatically extract a uniform sample of galaxies from the HIPASS data cubes and to determine the parameters of these galaxies. We have so far conducted tests involving both simulated sources injected into cubes with real noise and data from the Multibeam Deep survey. Results from these tests are encouraging.

Mid-infrared spectroscopic data on SN 1987A are reviewed. This spectral region contains the fine structure lines of a number of ions, incuding the iron group elements, together with recombination lines of hydrogen and helium. From about 9 months all these lines and the continuum have been effectively optically thin, and the [CoII] line strength and development yields an estimate of the parental 56Ni mass of 0.071 M⊙, very similar to the light curve estimates. At one year after the explosion the velocities appropriate to the hydrogenic and ionic regions are ∼ 2000 km s−1 and ∼ 1500 km s−1, respectively.

Apart from an excess between 8–9 μm which appears to be due to molecular SiO, there is no evidence of departure of the continuum from free-free emission, and no sign of any emission from dust. From the free-free continuum an ionization fraction of a few percent is derived for the hydrogen/helium envelope; this provides relative transparency in the mid infrared while the bound electrons provide the X and γ-ray opacity which is still considerable at 15 months.

The appearance of neutral ions at 15 months indicates that the ejecta temperatures are cooling, and that dust formation may be imminent.

A recent analysis of the spectra of about 2000 sources in the Culgoora-3 list (Slee 1977) of radio sources (Slee et al. 1981) has revealed some interesting features which may be the result of source evolution. The Culgoora-3 spectra were obtained by combining the 80 and 160 MHz flux densities from the Culgoora radioheliograph with other published flux data between 10 and 10,000 MHz; this is probably the most accurate set of spectra yet derived for a large number of sources selected for observation in a reasonably consistent manner. In addition to fitting the log S-log v data for each source with a straight line (its slope is the usual definition of spectral index) Slee et al. also fitted second-degree and third-degree polynomials to search for curvature in the spectra.

In this study, new observations and some results of statistical analyses are presented. The largest flare data set of DO Cep in the literature has been obtained with 89 flares detected in 67.61 hours of U-band flare patrol. First of all, the observations demonstrated that the star is one of the most active flare stars in respect to the computed flare frequency. Secondly, using the independent samples t-test, the detected flares were classified into two subtypes, and then they were modelled. Analysing the models demonstrated that the fast and slow flares occurring on the star can be separated with a critical value of the ratio of their decay time to rise time. The critical value was computed as 3.40. According to this value, the fast flare rate is 20.22%, while the slow flare rate is 79.78%. Besides, there is a 39.282 times difference between the energies of these two types of flares. However, the flare equivalent durations versus the flare rise times increase in similar ways for both groups. In addition, all the flares were modelled with the one-phase exponential association function. Analysing this model, the plateau value was found to be 2.810. Moreover, the half-life value was computed as 433.1 s from the model. The maximum flare rise time was found to be 1164 s, while the maximum flare total duration was found to be 3472 s. The results of the flare timescales indicate that the geometry of the flaring loop on the surface of the star might be similar to those seen on analogues of DO Cep. Consequently, considering both the half-life value and flare timescales, the flares detected on the surface of DO Cep get maximum energy in longer times, while the geometries of the flaring loops or areas get smaller.

Numerical simulations suggest that colliding molecular clouds induce gravitational collapse and may be responsible for star formation. We incorporate magnetic fields in these simulations and present preliminary results of an investigation of the influence of magnetic fields on star formation via this process.

The International Celestial Reference Frame suffers from significantly less observations in the southern hemisphere compared to the northern one. One reason for this is the historically low number of very long baseline interferometry radio telescopes in the south. The AuScope very long baseline interferometry array with three new telescopes on the Australian continent and an identical antenna in New Zealand were built to address this issue. While the overall number of observations in the south has greatly improved since then, a closer look reveals that this improvement is only true for strong radio sources (source flux densities >0.6 Jy). The new array of small very long baseline interferometry antennas has a relatively low baseline sensitivity so that only strong sources can be observed within a short integration time. A new observing strategy, the star scheduling mode, was developed to enable efficient observations of weak sources during geodetic sessions, through the addition of a single more sensitive antenna to the network. This scheduling mode was implemented in the Vienna very long baseline interferometry Software and applied in four 24-h sessions in 2016. These observations provide updated positions and source flux densities for 42 weak southern radio sources and significantly reduce the formal uncertainties for these sources. The star scheduling mode now allows the AuScope very long baseline interferometry array to undertake greater responsibility in monitoring sources in the southern sky, without significantly weakening the session for geodetic purposes.

This meeting provides the first opportunity for me to talk about the Australia Telescope as an established project. It has been formally approved at all levels and is now under way (see Fig. 1).

In recent years two 408 MHz surveys of the northern sky have been made to study the large-scale, low-surface-brightness features of the galactic background such as the loops and spurs (Haslam et al. 1970; Haslam et al. 1974). These surveys were designed to make maps down to the confusion limits of the telescopes used and to provide as far as practicable accurate calibration of the temperature scale and zero level for large-scale features. This work is complementary to the work of the large array telescopes; these telescopes can provide high resolution detail but they have lower surface brightness sensitivity, and have problems in determining the low-order terms which define the large-scale structure. The Parkes 408 MHz sourthern survey continues this work using the 64-m telescope to complete the coverage of the sky to the south pole. The project is a joint venture between the Max-Planck-Institut and CSIRO. For the southern survey it was felt desirable to measure the linear polarization distribution, besides making an accurate average temperature map in left-hand circular polarization (which is insensitive to variations of ionospheric Faraday effects). The previous surveys did not include linear polarization measurements.

We present a study of scintillation induced by the mid-latitude ionosphere. By implementing methods currently used in Interplanetary Scintillation studies to measure amplitude scintillation at low frequencies, we have proven it is possible to use the Murchison Widefield Array to study ionospheric scintillation in the weak regime, which is sensitive to structures on scales ${\sim}300$ m at our observing frequency of 154 MHz, where the phase variance on this scale was $0.06\, \textrm{rad}^{2}$ in the most extreme case observed. Analysing over 1000 individual 2-min observations, we compared the ionospheric phase variance with that inferred with previous measurements of refractive shifts, which are most sensitive to scales almost an order of magnitude larger. The two measurements were found to be highly correlated (Pearson correlation coefficient 0.71). We observed that for an active ionosphere, the relationship between these two metrics is in line with what would be expected if the ionosphere’s structure is described by Kolmogorov turbulence between the relevant scales of 300 and 2000 m. In the most extreme ionospheric conditions, the refractive shifts were sometimes found to underestimate the small-scale variance by a factor of four or more, and it is these ionospheric conditions that could have significant effects on radio astronomy observations.

A pilot project has been proceeded to map $1\, \textrm{deg}^2$ on the Galactic plane for radio recombination lines (RRLs) using the Five-hundred-metre Aperture Spherical Telescope (FAST). The motivation is to verify the techniques and reliabilities for a large-scale Galactic plane RRL survey with FAST aiming to investigate the ionised environment in the Galaxy. The data shows that the bandpass of the FAST 19 beam L-band is severely affected by radio frequency interferences and standing wave ripples, which can hardly be corrected by traditional low order polynomials. In this paper, we investigate a series of penalised least square (PLS) based baseline correction methods for radio astronomical spectra that usually contain weak signals with high level of noise. Three promising penalised least squares based methods, AsLS, arPLS, and asPLS are evaluated. Adopting their advantages, a modified method named rrlPLS is developed to optimise the baseline fitting to our RRL spectra. To check their effectiveness, the four methods are tested by simulations and further verified using observed data sets. It turns out that the rrlPLS method, with optimised parameter $\lambda=2\times10^8$ , reveals the most sensitive and reliable emission features in the RRL map. By injecting artificial line profiles into the real data cube, a further evaluation of profile distortion is conducted for rrlPLS. Comparing to simulated signals, the processed lines with low signal-to-noise ratio are less affected, of which the uncertainties are mainly caused by the rms noise. The rrlPLS method will be applied for baseline correction in future data processing pipeline of FAST RRL survey. Configured with proper parameters, the rrlPLS technique verified in this work may also be used for other spectroscopy projects.

Although only three antennas of the Australia Telescope Compact Array are currently operational, we have made use of the technique of bandwidth synthesis to make an image of the radio galaxy 2152 – 69. The three baselines were used to observe the source at three different frequencies, effectively resulting in nine baselines, which have been used to produce an image with a surprisingly high dynamic range, and with a slightly higher resolution than any existing image.

The production of such a worthwhile result, despite being made with a small subset of the capabilities of the Australia Telescope, bodes well for the future operation of the instrument.

The fact that Jupiter’s inner magnetosphere is not axially symmetric was originally demonstrated by ground-based radio measurements. Departures from symmetry are evident in the pattern of bursts occurring at decametre wavelengths and also in the characteristics of the polarized synchrotron emission observed at decimetre wavelengths. Direct measurements of Jupiter’s magnetic field, made from the Pioneer space probes, also indicate departures from an axially symmetric configuration.

We present preliminary results of a search for the optical counterparts of faint but energetic (1-13 keV) X-ray sources observed by the HEAO-1 satellite. The objects we have identified include Active Galactic Nuclei, Cataclysmic Variables, Be Binaries, and RS CVn Systems. A description is also given of the identification techniques and the X-ray database, which represents the most recent flux-limited all-sky survey of hard X-ray sources.

In Table I are given photometric data and spectral classes for some OB stars in galactic longitudes 298°-306°. The data have been obtained using a photoelectric photometer on the Reynolds reflector and the Meinel spectrograph on the 100 cm reflector at Siding Spring. Numbers refer to an OB star catalogue in preparation.

Powerful extragalactic radio sources are characterised by kpc-scale synchrotron emission associated with highly-collimated outflows of relativistic plasma. It is hypothesised that this outflowing plasma is powered by accretion processes concomitant with a central massive black hole. The radio morphologies of these sources comprise jets, lobes and for the most powerful sources, hotspots. At first sight, powerful extragalactic radio sources are a mixed group of objects, with the result that only some gross property delineates them further (e.g. steep-spectrum or flat-spectrum). However, there is accumulating observational evidence which suggests that it is the orientation of the radio axis to our line of sight that dictates their observed characteristics. This orientation dependence has been incorporated into ‘unified schemes’, which physically link apparently disparate radio source types via the random orientation of a ‘parent’ population on the plane of the sky. This paper summarises the ‘dual-population unified scheme’ paradigm investigated by Wall & Jackson (1997) and Jackson & Wall (1999) and discusses some of its implications with respect to radio source cosmology.