We describe the first results from the All-sky BRIght, Complete Quasar Survey (AllBRICQS), which aims to discover the last remaining optically bright quasars. We present 156 spectroscopically confirmed quasars (140 newly identified) having $|b|>10^{\circ}$. 152 of the quasars have Gaia DR3 magnitudes brighter than $B_{P}=16.5$ or $R_{P}=16$ mag, while four are slightly fainter. The quasars span a redshift range of $z=0.07-3.93$. In particular, we highlight the properties of J0529-4351 at $z=3.93$, which, if unlensed, is one of the most intrinsically luminous quasars in the Universe. The AllBRICQS sources have been selected by combining data from the Gaia and WISE all-sky satellite missions, and we successfully identify quasars not flagged as candidates by Gaia Data Release 3. We expect the completeness to be $\approx$96% within our magnitude and latitude limits, while the preliminary results indicate a selection purity of $\approx$96%. The optical spectroscopy used for source classification will also enable detailed quasar characterisation, including black hole mass measurements and identification of foreground absorption systems. The AllBRICQS sources will greatly enhance the number of quasars available for high-signal-to-noise follow-up with present and future facilities.

Student research projects are becoming either integral or optional components of Science curricula in several countries. They provide a valuable opportunity for high school students to experience many of the joys and frustrations that make up the intellectual challenge of Science. Astronomy is one branch of Science that lends itself to student projects. Student Research Projects (SRPs) can be individual, group or collaborative between groups in other schools or countries and may involve professional mentors. Use of the Internet and remote access telescopes allow students to undertake challenging research and make worthwhile contributions to professional programs. This paper presents case studies of student projects in optical and radio astronomy from Australian and overseas schools and details both the benefits and problems faced in conducting such projects. Student responses to involvement in projects are discussed. Potential areas for future collaboration and development are highlighted together with the need for more research as to the most effective ways to implement projects and develop student skills.

Atraditional problem in pulsar wind physics has been the nature of the pulsar wind.Ontheoretical grounds, the wind is expected to be dominated by Poynting flux associated with the outgoing magnetic field lines anchored on the polar caps of the rotating neutron star, while observations of the Crab Nebula demonstrate that the wind must be dominated by kinetic energy before the termination shock. Here we suggest a new approach to this old problem by studying the distributed currents rather than the singular sheet currents which have been the object of study in most work.We find that, at a distance well in between the light cylinder and the termination shock, current starvation sets in, and electric fields develop along the magnetic field lines which cause the current to dissipate and convert at least half of the Poynting flux into kinetic energy flux in a relatively thin shell. In the shell, at least half of the current closes across the magnetic field lines, the pitch of the spiralling magnetic field lines jumps downward strongly, and the outer pattern of magnetic field lines slips over the inner pattern.

Pulsars are unique astronomical objects in that their emission is in the form of a periodic pulse train. For most pulsars the pulse duty cycle is small, only a few per cent of the period. The shapes and intensities of individual pulses are in general quite variable. This is illustrated in Figure 1 which shows a series of individual pulses from PSR 1133 + 16. Despite this variation in shape of individual pulses, it is found that the mean or integrated pulse profile obtained by adding many pulses synchronously with the period is in most cases stable in shape.

For many years we have had evidence from solar radio bursts of violent mass motions in the solar corona: type II bursts reveal the passage of shock waves through the solar corona, and moving type IV bursts show that plasma and magnetic field travel to great distances without any sign of slowing down.

The Chatterton Astronomy Department of Sydney University, in collaboration with the Astronomy Group of Imperial College (London), has carried out a program of speckle interferometry on the 3.9 m Anglo-Australian Telescope (AAT). Over 2 km of film were exposed during the two observing sessions in November and December, 1978, and the analysis of this very large amount of data is being carried out at the present time.

We present maps in the visible emission lines of [S II] and the infrared emission lines of H2, at 2.12μm, for several bipolar outflow complexes which exhibit jet structures. A comparison of the morphology of this infrared emission and that seen in visible emission lines shows both the visible and the H2 emission exhibit clumpy structure on similar scales. It appears that the brightest H2 emission occurs at the working surfaces of the jets. Virtually no H2 emission is associated with the jets themselves.

Velocity profiles are presented for several objects and possible emission mechanisms are discussed.

We identify gravitationally bound structures in the Ursa Major region using positions, velocities and photometry from the Sloan Digital Sky Survey (SDSS DR7) and the Third Reference Catalogue of Bright Galaxies (RC3). A friends-of-friends algorithm is extensively tested on mock galaxy lightcones and then implemented on the real data to determine galaxy groups whose members are likely to be physically and dynamically associated with one another. We find several galaxy groups within the region that are likely bound to one another and in the process of merging. We classify 6 galaxy groups as the Ursa Major ‘supergroup’, which are likely to merge and form a poor cluster with a mass of ~ 8 × 1013 M⊙. Furthermore, the Ursa Major supergroup as a whole is likely bound to the Virgo cluster, which will eventually form an even larger system in the context of hierarchical structure formation. We investigate the evolutionary state of the galaxy groups in the Ursa Major region and conclude that these groups are in an early evolutionary state and the properties of their member galaxies are similar to those in the field.

The Murchison Widefield Array (MWA) is an electronically steered low-frequency (<300 MHz) radio interferometer, with a ‘slew’ time less than 8 s. Low-frequency (∼100 MHz) radio telescopes are ideally suited for rapid response follow-up of transients due to their large field of view, the inverted spectrum of coherent emission, and the fact that the dispersion delay between a 1 GHz and 100 MHz pulse is on the order of 1–10 min for dispersion measures of 100–2000 pc/cm3. The MWA has previously been used to provide fast follow-up for transient events including gamma-ray bursts (GRBs), fast radio bursts (FRBs), and gravitational waves, using systems that respond to gamma-ray coordinates network packet-based notifications. We describe a system for automatically triggering MWA observations of such events, based on Virtual Observatory Event standard triggers, which is more flexible, capable, and accurate than previous systems. The system can respond to external multi-messenger triggers, which makes it well-suited to searching for prompt coherent radio emission from GRBs, the study of FRBs and gravitational waves, single pulse studies of pulsars, and rapid follow-up of high-energy superflares from flare stars. The new triggering system has the capability to trigger observations in both the regular correlator mode (limited to ≥0.5 s integrations) and using the Voltage Capture System (VCS, 0.1 ms integration) of the MWA and represents a new mode of operation for the MWA. The upgraded standard correlator triggering capability has been in use since MWA observing semester 2018B (July–Dec 2018), and the VCS and buffered mode triggers will become available for observing in a future semester.

Regardless of whether or not all fast radio bursts (FRBs) repeat, those that do form a population with a distribution of rates. This work considers a power-law model of this population, with rate distribution $\Phi_r \sim R^{{\gamma_r}}$ between ${R_{\rm min}}$ and ${R_{\rm max}}$. The zDM code is used to model the probability of detecting this population as either apparently once-off or repeat events as a function of redshift, z, and dispersion measure, DM. I demonstrate that in the nearby Universe, repeating sources can contribute significantly to the total burst rate. This causes an apparent deficit in the total number of observed sources (once-off and repeaters) relative to the distant Universe that will cause a bias in FRB population models. Thus instruments with long exposure times should explicitly take repetition into account when fitting the FRB population. I then fit data from The Canadian Hydrogen Intensity Mapping Experiment (CHIME). The relative number of repeat and apparently once-off FRBs, and their DM, declination, and burst rate distributions, can be well explained by 50–100% of CHIME single FRBs being due to repeaters, with ${R_{\rm max}} > 0.75$ d$^{-1}$ above $10^{39}$ erg, and ${{\gamma_r}} = -2.2_{-0.8}^{+0.6}$. This result is surprisingly consistent with follow-up studies of FRBs detected by the Australian Square Kilometre Array Pathfinder (ASKAP). Thus the evidence suggests that CHIME and ASKAP view the same repeating FRB population, which is responsible not just for repeating FRBs, but the majority of apparently once-off bursts. For greater quantitative accuracy, non-Poissonian arrival times, second-order effects in the CHIME response, and a simultaneous fit to the total FRB population parameters, should be treated in more detail in future studies.

The H2O Southern Galactic Plane Survey (HOPS) has observed 100 deg2 of the Galactic plane, using the Mopra radio telescope to search for emission from multiple spectral lines in the 12-mm band (19.5–27.5 GHz). Perhaps the most important of these spectral lines is the 22.2-GHz water-maser transition. We describe the methods used to identify water-maser candidates and subsequent confirmation of the sources. Our methods involve a simple determination of likely candidates by searching peak emission maps, utilising the intrinsic nature of water-maser emission, spatially unresolved and spectrally narrow-lined. We estimate completeness limits and compare our method with results from the duchamp source finder. We find that the two methods perform similarly. We conclude that the similarity in performance is due to the intrinsic limitation of the noise characteristics of the data. The advantages of our method are that it is slightly more efficient in eliminating spurious detections and is simple to implement. The disadvantage is that it is a manual method of finding sources and so is not practical on datasets much larger than HOPS, or for datasets with extended emission that needs to be characterised. We outline a two-stage method for the most efficient means of finding masers, using duchamp.

A complete ring of neutral hydrogen gas (HI) in the LGG 138 group of galaxies has been found. The HI mass of the ring is greater than 109, and the gas appears to be rotating with a projected circular speed of ∼200 km s−1. Two bright galaxies are enclosed by the ring, both having radial velocities consistent with membership of the group. Faint stellar emission extends to the radial distance of the HI ring, where a small but distinct colour discontinuity of between 0·05 and 0·20 magnitudes is detected. Three simple models for the formation of the system are briefly described, the most likely appearing to be a past gas-sweeping collision between one of the two bright galaxies and an outside intruder, with the colour break being partly due to an expanding density wave that is triggering star formation, and partly to a different stellar population that has been collected from the outskirts of the intruder.

We provide a set of analytic fits to the radii of pre-mainsequence stars in the mass range 0.1 < M/M⊙ < 8.0. We incorporate the formulae in N-body cluster models for evolution from the beginning of pre-main sequence. In models with 1 000 stars and high initial cluster densities, pre-mainsequence evolution causes roughly twice the number of collisions between stars than in similar models with evolution begun only from the zero-age main sequence. The collisions are often all part of a runaway sequence that creates one relatively massive star.

We follow up on a report by Vacca et al. (2018) of 28 candidate large-scale diffuse synchrotron sources in an 8° × 8° area of the sky (centred at RA 5h0m0s; Dec 5°48ʹ00ʹʹ). These sources were originally observed at 1.4 GHz using a combination of the single-dish Sardinia Radio Telescope and archival NRAO VLA Sky Survey data. They are in an area with nine massive galaxy clusters at $z \approx 0.1$ and are candidates for the first detection of filaments of the synchrotron cosmic web. We attempt to verify these candidate sources with lower frequency observations at 154 MHz with the Murchison Widefield Array and at 887 MHz with the Australian Square Kilometre Array Pathfinder (ASKAP). We use a novel technique to calculate the surface brightness sensitivity of these instruments to show that our lower frequency observations, and in particular those by ASKAP, are ideally suited to detect large-scale, extended synchrotron emission. Nonetheless, we are forced to conclude that none of these sources are likely to be synchrotron in origin or associated with the cosmic web.

In 1983 ultra high energy γ-rays were detected from Cygnus X-3. This was of particular interest since it is the first identifiable source of cosmic rays. Since then, there has been an explosion of interest in the field with more than twenty air shower arrays planned or being used to search for γ-rays at energies above 1014 eV. Observational techniques for both very high energy and ultra high energy γ-ray astronomy are described and existing and proposed experiments reviewed with particular reference to their geographical locations. The results obtained so far are summarised together with some of the models proposed to explain them.

We are undertaking an observational program using the ATCA to monitor the intraday variability (IDV) of a sample of sources at 4.8 and 8.6 GHz. The sources were selected to include the known strong southern IDV sources plus a number of sources whose IDV was recently discovered. The present monitoring program will extend over a full year in order to search for any annual cycle that may be present in the long-term IDV characteristics of these sources. In this paper we discuss the observing strategy and data analysis, and present the first results from our observations.

I review the literature covering the issue of interstellar extinction towards the Milky Way bulge, with emphasis placed on findings from planetary nebulae, RR Lyrae, and red clump stars. I also report on observations from HI gas and globular clusters. I show that there has been substantial progress in this field in recent decades, most particularly from red clump stars. The spatial coverage of extinction maps has increased by a factor ~ 100 × in the past 20 yr, and the total-to-selective extinction ratios reported have shifted by ~ 20–25%, indicative of the improved accuracy and separately, of a steeper-than-standard extinction curve. Problems remain in modelling differential extinction, explaining anomalies involving the planetary nebulae, and understanding the difference between bulge extinction coefficients and ‘standard’ literature values.

Stewart (1978) has reported four moving type IV bursts observed with the Culgoora radio heliograph at 43, 80 and 160 MHz. After an early phase, the brightness temperatures of the observed bursts decreased with increasing frequency and with time. The highest brightness temperature observed at 43 MHz was 1010K, and it seems that the brightness temperature would have been still higher at even lower frequencies. Existing theoretical ideas on moving type IV bursts are based on data (at 80 MHz primarily) which included no brightness temperatures in excess of 109K. the accepted interpretation involved gyro-synchrotron radiation from mildly relativistic electrons (energies ≈ 100 keV); reabsorption by the electrons themselves restricts the brightness temperature to less than about 100 keV ≈ 109K (Wild and Smerd 1972, Dulk 1973). Stewart’s (1978) new data at 43 MHz require that this accepted interpretation be modified; he has suggested that higher energy electrons are involved. An alternative suggestion is explored here, namely that the absorption might be negative. In other words, the high brightness temperatures observed could be due to a gyro-synchrotron maser involving electrons with energies of about 100 keV.

NGC 253 is the major member of the Sculptor group of galaxies. It is classified SAB(s)c by de Vaucouleurs, de Vaucouleurs and Corwin (1976) and is almost edge-on. Previous studies have revealed a peculiar velocity field near the nucleus (e.g. Ulrich 1978). The nucleus is also a moderately strong radio and infrared source (Beck et al. 1979, Klein and Emerson 1981, Elias et al. 1978, Telesco and Harper 1980, Rieke et al. 1980).

We first present a recently developed three-dimensional chemodynamic code for galaxy evolution from the Kiev–Kiel collaboration. It follows the evolution of all components of a galaxy, such as dark matter, stars, molecular clouds and diffuse interstellar matter. Dark matter and stars are treated as collisionless N-body systems. The interstellar matter is numerically described by a smoothed particle hydrodynamics approach for the diffuse (hot) gas and a sticky particle scheme for the (cool) molecular clouds. Physical processes, such as star formation, stellar death, or condensation and evaporation processes of clouds interacting with the ISM are described locally. An example application of the model to a star forming dwarf galaxy will be shown for comparison with other codes. Secondly, we will discuss new kinds of exotic chemodynamic processes, as they occur in dense gas–star systems in galactic nuclei, such as non-standard ‘drag’-force interactions, destructive and gas-producing stellar collisions. Their implementation in one-dimensional dynamic models of galactic nuclei is presented. Future prospects to generalise these to three dimensions are in progress and will be discussed.