Solar metre-wave noise storms commonly show continuum and short-lived narrow-band bursts (Type I) at high frequencies and fast-drift bursts (Type III) at low frequencies (Malville 1962; Hanasz 1966; Boischot et al. 1970; Moller-Pedersen 1974; see also Figs. 2-3 of this paper). The Type I and Type III emissions have the same sense of polarization (Komesaroff 1958; Suzuki 1978). Impressed by this spectral association, Malville (1962) and Boischot et al. (1970) suggested that the two types of emission might be excited by the same electron stream. However, Type I emission is associated with sunspots and strong photospheric magnetic fields (McCready et al. 1947; Payne-Scott and Little 1951; Le Squeren 1963) and for this reason Kai (1970) suggested that Type I emission arises on strong closed magnetic loops. Type III emission, by contrast, almost certainly arises on open or quasi-open (large-loop) magnetic field lines (Wild et al. 1959, 1963). Thus on these models one would expect Type I and Type III emissions to arise from different magnetic regimes and different areas of the Sun. Kai’s (1970) and Stewart and Labrum’s (1972) Culgoora radioheliograph observations, which suggested that Type I and Type III sources are always separated on the Sun, seemed to clinch the matter. Kai’s model and his statement ‘Type III sources avoid the precise location of Type I storm centres’ gained wide acceptance (e.g. Boischot et al. 1971; Elgaroy 1977; Stewart 1977).

Although scientific astronomy has a long and illustrious history in Australia, it was not until 1895 that the first astronomical society was formed. This was the New South Wales Branch of the British Astronomical Association (see B.A.A. 1894-5; Gale 1895a,b), and before the end of the century it was joined by others in Melbourne and Brisbane (B.A.A. 1897-8; Editor’s Note 1979; Ellery 1901:13; Thomson 1897). These societies and their predecessors, the Astronomy Branches of the Royal Societies of New South Wales and South Australia (Waters 1980), were the mainstay of astronomical activity – both professional and amateur – in nineteenth century Australia, providing as they did regular meetings, library facilities, and avenues for publication and celestial observation.

Observations of the distribution of millimetre-wavelength brightness over the quiet Sun provide an important test of models of the solar chromosphere. The author and colleagues have recently carried out two investigations of the quiet-Sun brightness at 3 mm wavelength — one by means of a total eclipse observation (Labrum et al. 1978) and the other by aperture synthesis with a two-element interferometer (Archer et al. 1978). I present here a preliminary discussion of these and other measurements of millimetre-wavelength brightness distributions and of their interpretation in terms of chromospheric structure.

On 1968 October 30 a large solar flare (importance 3B to 4B) began at approximately 23h42m U.T. We present here a preliminary account of the associated radio emission.

It is evident that the limited duration of a single rocket or balloon flight is a severe handicap to the study of variable X-ray sources like Cen XR-2, the early history of which can only be conjectured from the few available rocket observations. The whole question of the variability of X-ray sources remains in doubt because of the difficulty of relating infrequent high-altitude flux measurements of short duration made with a variety of instruments. There are obvious advantages in a method of monitoring celestial X-ray fluxes from the ground for prolonged periods of time. Such a method has recently been found and, although presently restricted to strong sources like Sco XR-1 and Cen XR-2, is capable of considerable refinement.

The atmospheric 14C record, the corresponding WM values derived from a carbon reservoir model, auroral numbers and the Zurich relative annual sunspot numbers all demonstrate a substantial downturn in solar activity for the duration of solar cycles 5 and 6. This reduction is also imbedded in some dendrochronological proxy data sets, which describe an annual index radial growth rate for trees at high-altitude sites. A significant lagged correlation can exist between tree-ring indices and the 11–year solar cycle during periods of high solar activity, a feature which is not evident during quiescent periods.

Ultra-compact H ii (UC HII) regions are an important phase in the formation and early evolution of massive stars and a key component of the interstellar medium (ISM). The main objectives of this work are to study the young stellar population associated with the G45.07+0.13 and G45.12+0.13 UC HII regions, as well as the ISM in which they are embedded. We determined the distribution of the hydrogen column density (N( $\mathrm{H}_2$ )) and dust temperature ( $T_d$ ) in the molecular cloud using Modified blackbody fitting on Herschel images obtained in four bands: 160, 250, 350, and $500\,\unicode{x03BC}\mathrm{m}$ . We used near-, mid-, and far-infrared photometric data to identify and classify the young stellar objects (YSOs). Their main parameters were determined by the radiation transfer models. We also constructed a colour-magnitude diagram and K luminosity functions (KLFs) to compare the parameters of stellar objects with the results of the radiative transfer models. We found that N( $\mathrm{H}_2$ ) varies from ${\sim}3.0 \times 10^{23}$ to $5.5 \times 10^{23}\,\mathrm{cm}^{-2}$ within the G45.07+0.13 and G45.12+0.13 regions, respectively. The maximum $T_d$ value is 35 K in G45.12+0.13 and 42 K in G45.07+0.13. $T_d$ then drops significantly from the centre to the periphery, reaching about 18–20 K at distances of ${\sim}2.6$ and ${\sim}3.7\,\mathrm{pc}$ from InfraRed Astronomical Satellite (IRAS) 19110+1045 (G45.07+0.13) and IRAS 19111+1048 (G45.12+0.13), respectively. The gas plus dust mass value included in G45.12+0.13 is ${\sim}3.4 \times 10^5\,\mathrm{M}_\odot$ and ${\sim}1.7 \times 10^5\,\mathrm{M}_\odot$ in G45.07+0.13. The UC HII regions are connected through a cold ( $T_d = 19\,\mathrm{K}$ ) bridge. The radial surface density distribution of the identified 518 YSOs exhibits dense clusters in the vicinity of both IRAS sources. The parameters of YSOs in the IRAS clusters (124 objects) and 394 non-cluster objects surrounding them show some differences. About 75% of the YSOs belonging to the IRAS clusters have an evolutionary age greater than $10^6$ yr. Their slope $\alpha$ of the KLF agrees well with a Salpeter-type initial mass function (IMF) ( $\gamma = 1.35$ ) for a high mass range (O–F stars, $\beta \sim 2$ ) at 1 Myr. The non-cluster objects are uniformly distributed in the molecular cloud, 80% of which are located to the right of the 0.1 Myr isochrone. The slope $\alpha$ of the KLF of non-cluster objects is $0.55\,\pm\,0.09$ , corresponding better to a Salpeter-type IMF for low-mass objects (G–M stars, $\beta \sim 1$ ). Our results show that two dense stellar clusters are embedded in these two physically connected UC HII regions. The clusters include several high- and intermediate-mass zero-age main sequence stellar objects. Based on the small age spread of the stellar objects, we suggest that the clusters originate from a single triggering shock. The extended emission observed in both UC HII regions is likely due to the stellar clusters.

We compare the total flux density variations and the VLBI structural variations in a sample of 27 gamma-ray blazars. We find that all the radio variations are due to shocks; the flux of the underlying jet remains constant. A large fraction of the shocks grow and fade within the innermost 0.1 mas, appearing only as ‘core flares’. Comparisons with the EGRET data show that gamma-ray flares must come from the shocks, not from the jet. At the time of an EGRET flare, the shock is typically already over a parsec downstream from the radio core, beyond the accretion disk and/or the broad line region (BLR) photon fields. Thus, present models for gamma-ray production are inadequate, since they typically model the gamma-ray inverse Compton flux as coming from the jet, with significant disk or BLR external Compton components.

The European Southern Observatory Faint Object Spectrograph and Camera v2 is one of the workhorse instruments on ESO’s New Technology Telescope, and is one of the most popular instruments at La Silla observatory. It is mounted at a Nasmyth focus, and therefore exhibits strong, wavelength and pointing-direction-dependent instrumental polarisation. In this document, we describe our efforts to calibrate the broadband imaging polarimetry mode, and provide a calibration for broadband B, V, and R filters to a level that satisfies most use cases (i.e. polarimetric calibration uncertainty ~0.1%). We make our calibration codes public. This calibration effort can be used to enhance the yield of future polarimetric programmes with the European Southern Observatory Faint Object Spectrograph and Camera v2, by allowing good calibration with a greatly reduced number of standard star observations. Similarly, our calibration model can be combined with archival calibration observations to post-process data taken in past years, to form the European Southern Observatory Faint Object Spectrograph and Camera v2 legacy archive with substantial scientific potential.

In traditional antenna design, metal components are not placed in the central part of the antenna as they change the characteristics of near field radiation. However, we show that placing a metal ring in the centre of the strip lines, which connect the ends of folded high-frequency dipoles, does not damage the performance of the feed. Instead it significantly improves the voltage standing wave ratio of the feed whilst other performance indicators are not compromised. Thus, our findings show an excellent way of improving the wide band feed. Based on this foundation, a new circularly polarised feed for operation between 0.4 to 2 GHz is introduced for the Chinese Spectral Radioheliograph in this paper. The issue of a feed impedance matching network is investigated. By optimising the impedance matching, the performance of the feed is enhanced with respect to the previous realisations of the Eleven feed. The simulation and experimental results show that the gain of the feed is about 10 dBi, and the VSWR is less than 2:1. In addition, the feed has a low axial ratio, fixed phase centre location, and constant beam width in the range of 0.4 to 2 GHz.

We present spectroscopic and photometric analysis of the eclipsing binary KIC 7385478. We find that the system is formed by F1V + K4III–IV components. Combining results from analysis of spectroscopic data and Kepler photometry, we calculate masses and radii of the primary and the secondary components as M1 = 1.71 ± 0.08 M⊙, M2 = 0.37 ± 0.04 M⊙ and R1 = 1.59 ± 0.03 R⊙, R2 = 1.90 ± 0.03 R⊙, respectively. Position of the primary component in HR diagram is in the region of γ Doradus type pulsators and residuals from light curve modelling exhibit additional light variation with a dominant period of ~ 0.5 d. These are clear evidences of the γ Doradus type pulsations on the primary component. We also observe occasional increase in amplitude of the residuals, where the orbital period becomes the most dominant period. These may be attributed to the cool star activity originating from the secondary component.

The interstellar extinction law in 20 open star clusters namely, Berkeley 7, Collinder 69, Hogg 10, NGC 2362, Czernik 43, NGC 6530, NGC 6871, Bochum 10, Haffner 18, IC 4996, NGC 2384, NGC 6193, NGC 6618, NGC 7160, Collinder 232, Haffner 19, NGC 2401, NGC 6231, NGC 6823, and NGC 7380 have been studied in the optical and near-IR wavelength ranges. The difference between maximum and minimum values of E(B − V) indicates the presence of non-uniform extinction in all the clusters except Collinder 69, NGC 2362, and NGC 2384. The colour excess ratios are consistent with a normal extinction law for the clusters NGC 6823, Haffner 18, Haffner 19, NGC 7160, NGC 6193, NGC 2401, NGC 2384, NGC 6871, NGC 7380, Berkeley 7, Collinder 69, and IC 4996. We have found that the differential colour-excess ΔE(B − V), which may be due to the occurrence of dust and gas inside the clusters, decreases with the age of the clusters. A spatial variation of colour excess is found in NGC 6193 in the sense that it decreases from east to west in the cluster region. For the clusters Berkeley 7, NGC 7380, and NGC 6871, a dependence of colour excess E(B − V) with spectral class and luminosity is observed. Eight stars in Collinder 232, four stars in NGC 6530, and one star in NGC 6231 have excess flux in near-IR. This indicates that these stars may have circumstellar material around them.

The X-ray binary 4U 1543–624 has been provisionally identified as an ultra-compact system with an orbital period of ≃ 18 min. We have carried out time-resolved optical imaging of the binary to verify the ultra-short orbital period. Using 140 min of high-cadence r′-band photometry, we recover the previously-seen sinusoidal modulation and determine a period P = 18.20 ± 0.09 min. In addition, we also see a 7.0 × 10−4 mag min−1 linear decay, likely related to variations in the source's accretion activity. Assuming that the sinusoidal modulation arises from X-ray heating of the inner face of the companion star, we estimate a distance of 6.0–6.7 kpc and an inclination angle of 34°–61° (90% confidence) for the binary. Given the stability of the modulation, we can confirm that the modulation is orbital in origin and 4U 1543–624 is an ultra-compact X-ray binary.

A new high time resolution observing mode for the Murchison Widefield Array (MWA) is described, enabling full polarimetric observations with up to $30.72\,$ MHz of bandwidth and a time resolution of ${\sim}$ $0.8\,\upmu$ s. This mode makes use of a polyphase synthesis filter to ‘undo’ the polyphase analysis filter stage of the standard MWA’s Voltage Capture System observing mode. Sources of potential error in the reconstruction of the high time resolution data are identified and quantified, with the $S/N$ loss induced by the back-to-back system not exceeding $-0.65\,$ dB for typical noise-dominated samples. The system is further verified by observing three pulsars with known structure on microsecond timescales.

We have undertaken a detailed investigation, based on the available evidence, of the sequence of events that led to the historical discovery of the first quasar, 3C 273.

The Australian SKA Pathfinder (ASKAP) radio telescope has carried out a survey of the entire Southern Sky at 887.5 MHz. The wide area, high angular resolution, and broad bandwidth provided by the low-band Rapid ASKAP Continuum Survey (RACS-low) allow the production of a next-generation rotation measure (RM) grid across the entire Southern Sky. Here we introduce this project as Spectral and Polarisation in Cutouts of Extragalactic sources from RACS (SPICE-RACS). In our first data release, we image 30 RACS-low fields in Stokes I, Q, U at 25$^{\prime\prime}$ angular resolution, across 744–1032 MHz with 1 MHz spectral resolution. Using a bespoke, highly parallelised, software pipeline we are able to rapidly process wide-area spectro-polarimetric ASKAP observations. Notably, we use ‘postage stamp’ cutouts to assess the polarisation properties of 105912 radio components detected in total intensity. We find that our Stokes Q and U images have an rms noise of $\sim$80 $\unicode{x03BC}$Jy PSF$^{-1}$, and our correction for instrumental polarisation leakage allows us to characterise components with $\gtrsim$1% polarisation fraction over most of the field of view. We produce a broadband polarised radio component catalogue that contains 5818 RM measurements over an area of $\sim$1300 deg$^{2}$ with an average error in RM of $1.6^{+1.1}_{-1.0}$ rad m$^{-2}$, and an average linear polarisation fraction $3.4^{+3.0}_{-1.6}$ %. We determine this subset of components using the conditions that the polarised signal-to-noise ratio is $>$8, the polarisation fraction is above our estimated polarised leakage, and the Stokes I spectrum has a reliable model. Our catalogue provides an areal density of $4\pm2$ RMs deg$^{-2}$; an increase of $\sim$4 times over the previous state-of-the-art (Taylor, Stil, Sunstrum 2009, ApJ, 702, 1230). Meaning that, having used just 3% of the RACS-low sky area, we have produced the 3rd largest RM catalogue to date. This catalogue has broad applications for studying astrophysical magnetic fields; notably revealing remarkable structure in the Galactic RM sky. We will explore this Galactic structure in a follow-up paper. We will also apply the techniques described here to produce an all-Southern-sky RM catalogue from RACS observations. Finally, we make our catalogue, spectra, images, and processing pipeline publicly available.

In 1931 Karl Jansky established that radio noise was associated with our own galaxy–the Milky Way. For a decade and a half there was little follow-up; those of us who were associated with low frequency radar during the war regarded it as a nuisance which could limit the detection range of enemy aircraft. Grote Reber was the first to make a detailed but fairly low resolution map of the radiation from the galaxy showing, for the first time, some detailed structure. The event which we celebrate today occurred when Gordon Stanley, Bruce Slee and I showed that three of the discrete sources that we had discovered could be identified with visual objects. One was with the Crab Nebula, a supernova remnant within our own galaxy and the other two with galaxies, far beyond our own system, in the constellations of Virgo and Centaurus. Thus began extragalactic radio astronomy. In 1982 at the Noosa meeting of the ASA, I gave an account of those early years, later to be published in the ASA Proceedings. As I don’t wish to repeat myself, I propose to speak on my involvement in a later development which was to extend the observable scale of the universe to look-back times as great as the age of the oldest stars in our own system. The first important step was Graham Smith’s identification of Cygnus A with a galaxy that was much fainter than our two. The spectrum by Minkowski revealed an instrinsically highly-luminous galaxy with strong emission lines and opened up the possibility of discovering similar objects at significantly greater distance. This was achieved nine years later with the building of the Owens Valley Observatory and my title of ‘Radiophysics in Exile’ comes from the fact the observatory owed its existence and early successes very largely to past and future staff members of Radiophysics. They were, in order of appearance, J. G. Bolton, G. J. Stanley, K. C. Westfold, J. A. Roberts, V. Radhakrishnan, D. Morris and K. I. Kellermann. Some still bear . the scars–Westfold left the tip of one index finger in the Owens Valley!

At the centre of the Parkes 64—m radio telescope a region of diameter 17 m has recently been resurfaced to improve its efficiency at high frequencies. The first measurements using this section have been made at 22 GHz, in observations of both continuum sources and water tfapour masers. For these observations the receiver front-end used a mixer cooled in liquid nitrogen, followed by a 5 GHz cryogenic parametric amplifier as a second stage. The option of switching against an offset horn was available and the total systemnoise temperature was ∽ 750 K.

Observations of the 21 cm line of neutral hydrogen can provide several integral properties of galaxies. The systemic velocity Vsvs indicates the distance Δ via the Hubble relation or through group membership. The integral over velocity of the flux density profile, ∫S dV, immediately yields the amount of neutral hydrogen in the galaxy: M H ∝ Δ2∫S dV (neglecting optical-depth effects). The profile width W and the inclination i (derived from the optical axial ratio), together with the (optical) angular diameter a, supply the ‘indicative mass’ Mi ∝ (W/sin i)2 a △ (Bottinelli et al. 1968; Balkowski 1973), which is a fair estimate of the total mass of the system. In addition, as shown by Tully and Fisher (1976), the profile width is a good indicator of luminosity L. The quantities and L, which are (at least roughly) representative of the amounts of matter and of gaseous and luminous material in the system, give an indication of its composition. Together with the linear diameter a△, these quantities contain clues as to galaxy formation and evolution.

The Molonglo cross-type radiotelescope has been in operation since 1967 and it is expected that its principal task, the fundamental sky survey, will be completed within the next few years. This by no means represents the end of the useful life of the instrument but we have been investigating modifications to extend further its usefulness. The most desirable modification appears to be a substantial increase in operating frequency to improve the resolution and positional accuracy.