In this review I present observational results of active galactic nuclei that my colleagues and I have recently obtained. I discuss their significance in terms of unification schemes and evolutionary scenarios.

Statistical information on 8280 individual radio observations of binary stars, predominantly at 8·4 GHz using the Parkes 64 m antenna, is presented. Three main groups are distinguished: (i) RS CVn stars, (ii) classical Algol binaries (EA2s), and (iii) detached pairs of generally early type (ETBs).

The RS CVn stars more frequently gave rise to detectable fluxes, while the ETBs, in these data, are a small and rather heterogeneous class. The Algols' emission appears to increase near conjunction phases, though we cannot clearly distinguish any special property of the Algols' phase-dependent behaviour that is not also shared by the RS CVn binaries. Both these categories' data show a bimodal, phase-dependent pattern to the distribution of detections, suggesting that these binary types share similar underlying physical properties, though there could also be other factors at play. The sample sizes of the Algols and particularly the ETB detections are too small for effective, discriminatory statistics, however.

Pulsars may be born with a short rotation period of milliseconds with the magnetic field amplified through dynamo processes up to ∼1015–1016 G. Such millisecond magnetars spin down rapidly, emitting bursts of high-energy neutrinos and gamma rays. Specifically, acceleration of ions in both the polar gap (as in a normal pulsar) and the relativistic magnetar wind is considered. In both cases ions can be accelerated to ultra-high energies and these energetic ions can lead to production of high-energy neutrinos and gamma rays through interaction with thermal radiation from the hot neutron star or the heated inner boundary region of the stellar envelope as the result of the deposition of energy by the magnetar wind. The detectability of the neutrino flux by a kilometre-scale neutrino detector such as the planned IceCube neutrino observatory is discussed.

We investigate the effect of duplicity on stellar yields of carbon, nitrogen, and oxygen. Populations of single and binary stars are modelled and the yields calculated for the whole population. The effects of explosive nucleosynthesis in novae and supernovae are included but by artificially removing these effects from our populations we determine the influence of a binary companion on asymptotic giant branch yields of the CNO elements.

We investigate the production of aluminium and magnesium in asymptotic giant branch models covering a wide range in mass and composition. We evolve models from the pre-main sequence, through all intermediate stages, to near the end of the thermally-pulsing asymptotic giant branch phase. We then perform detailed nucleosynthesis calculations from which we determine the production of the magnesium and aluminium isotopes as a function of the stellar mass and composition. We present the stellar yields of sodium and the magnesium and aluminium isotopes. We discuss the abundance predictions from the stellar models in reference to abundance anomalies observed in globular cluster stars.

High-resolution échelle spectra of 42 nearby southern solar-type stars have been obtained, in a search for young, single, active, and rapidly rotating sun-like stars suitable for Doppler imaging and Zeeman Doppler imaging studies. As a result of this survey, 13 stars were determined to be youthful with ages less than 600 Myr (Hyades age) and eight of these were found to have projected rotational velocities in excess of 15 km s−1. In addition, five spectroscopic binary systems were identified. Of those stars observed for this survey, HD 106506 is the most outstanding target for mapping active regions. It is an apparently young and single star with rapid rotation (v sin i ∼ 80 km s−1), strong Hα chromospheric activity (log R′Hα ∼ −4.2), and deformation of the spectral line profiles indicating the presence of large starspots.

Infrared J and K photometry has been obtained of all red giants in the half square degree region of the LMC bar searched for variables using the MACHO database byWood et al. (1999). The K–log P diagram shows the five distinct period–luminositysequences which are also evident in the MACHO photometry. The K–log P plot allowsidentification of the Mira sequence from among the five observed sequences. As shown in Wood et al. (1999), comparison of observed periods, luminosities and period ratios with theoretical models identifies Miras unambiguously as radial fundamental mode pulsators, while semi-regular variables can be pulsating in the first, second or third overtone, or even the fundamental mode. All these variables lie on just three of the five distinct sequences, and they all appear to be on the AGB. The nature of the variability of stars on the other two sequences is currently unknown. Possibilities include contact and semi-detached binaries, rotating stars with giant star spots, episodic dust formation, rotationally stabilised non-radial g− modes and strange pulsation modes caused by convection–pulsation interaction. These possibilities are discussed.

The future of centimetre and metre-wave astronomy lies with the Square Kilometre Array (SKA), a telescope under development by a consortium of 17 countries that will be 50 times more sensitive than any existing radio facility. Most of the key science for the SKA will be addressed through large-area imaging of the Universe at frequencies from a few hundred MHz to a few GHz. The Australian SKA Pathfinder (ASKAP) is a technology demonstrator aimed in the mid-frequency range, and achieves instantaneous wide-area imaging through the development and deployment of phased-array feed systems on parabolic reflectors. The large field-of-view makes ASKAP an unprecedented synoptic telescope that will make substantial advances in SKA key science. ASKAP will be located at the Murchison Radio Observatory in inland Western Australia, one of the most radio-quiet locations on the Earth and one of two sites selected by the international community as a potential location for the SKA. In this paper, we outline an ambitious science program for ASKAP, examining key science such as understanding the evolution, formation and population of galaxies including our own, understanding the magnetic Universe, revealing the transient radio sky and searching for gravitational waves.

The ionised gas regions, which are the main tracers of the spiral arms, can be used for the study and determination of the spiral structure of our Galaxy. Towards this goal, the Marseille Observatory elaborated and developed an instrument, using a scanning Fabry–Perot interferometer, particularly suited for the observation of extended objects. A survey of the southern Galactic plane then started at the beginning of 1990. The major instrumental aim is to obtain spectral information, and therefore the ionised gas kinematics, in each pixel of the observed fields. Already 300 fields of 38′×38′ have been observed in Hα with a spatial resolution of 9″×9″, covering almost the entire fourth quadrant of the Galactic plane, and numerous discrete HII regions have been detected, as well as diffuse emission which is widely distributed. Also, the Magellanic Clouds have been studied using the same instrument.

Four massive, early-type stars, three of which are confirmed binaries, have been observed with the Australia Telescope Compact Array at 1.4, 2.4, 4.8, and 8.6 GHz. The earliest star cataloged so far, HD 93129A, was also observed at 17.8 and 24.5 GHz. Here we present an analysis of the spectra as well as the structure of the stellar systems. All four spectra show clear evidence of non-thermal emission, indicative of a binary system with a colliding wind region. We discuss the magnetic field of the emitting region of HD 93129A and make predictions on the radiation at high energies. Archive X-ray observations towards the target sources are also investigated and interpreted in the light of the non-thermal emission detected.

We validate the baryonic Tully–Fisher (TF) relation by exploring the Tully–Fisher (TF) and BTF properties of optically and Hi-selected disk galaxies.The data includes galaxies from Sakai et al. (2000) calibrator sample, McGaugh et al. (2000: M2000) I-band sample,and 18 newly acquired Hi-selected field dwarf galaxies observed with the ANU 2.3-mtelescope and the ATNF Parkes telescope(Gurovich 2005a).

As in M2000, we re-cast the TF and BTF relations as relationships between baryon mass and W 20. First we report some numerical errors in M2000. Then, we calculate weighted bi-variate linear fits to the data, and finally we compare the fits of the intrinsically fainter dwarfs with the brighter galaxies of Sakai et al. (2000). With regards to the local calibrator disk galaxies of Sakai et al. (2000), our results suggest that the BTF relation is indeed tighter than the TF relation and that the slopes of the BTF relations are statistically flatter than the equivalent TF relations. Further, for the fainter galaxies which include the I-band M2000 and Hi-selected galaxies of Gurovich's sample, we calculate a break from a simple power law model because of what appears to be real cosmic scatter. Not withstanding this point, the BTF models are marginally better models than the equivalent TF ones with slightly smaller Χred 2 values.

This paper summarises our work on the role of magnetic fields in accretion disks presented in two papers elsewhere. In the first part (a summary of part of Kuncic & Bicknell 1999), we present a formal development of the equations governing the structure of an accretion disk containing magnetohydrodynamic turbulence. The importance of the different terms in the energy and momentum equations is discussed, and a parametrisation of the unresolved processes is suggested that could be used to make further progress. We briefly explore whether an MHD accretion disk can transport a significant part of the gravitational power into a corona by buoyancy. In the second part, we present some exploratory calculations of the vertical structure of accretion disks, in which non-local dissipation of energy due to the buoyant transport of magnetic field energy is taken into account. It is argued that the efficiency of buoyant magnetic transport depends very strongly on the size of the coherent magnetic regions. If the size of the buoyant cells is not very close to the disk thickness, magnetic energy generated by dynamo action inside the disk will be dissipated locally, and will not be available to transport a significant part of the accretion luminosity into a corona.

The vast quantities of data produced by modern radio telescopes require advanced visualisation tools to explore them. The quantitative nature of astronomy requires more than just representing data visually. This paper discusses research in displaying, and using, a three-dimensional ‘cursor’ in amorphous, noisy data which often resemble wispy tendrils.

We present an analysis of Li abundances in low mass stars (LMS) during the Red Giant Branch (RGB) and Asymptotic Giant Branch (AGB) stages, based on a new determination of their luminosities and evolutionary status. By applying recently suggested models for extra-mixing, induced by magnetic buoyancy, we show that both Li-rich and Li-poor stars can be accounted for. The simplest scenario implies the development of fast instabilities on the RGB, where Li is produced. When the fields increase in strength, buoyancy slows down and Li is destroyed. 3He is consumed, at variable rates. The process continues on the AGB, where however moderate mass circulation rates have little effect on Li due to the short time available. O-rich and C-rich stars show different histories of Li production/destruction, possibly indicative of different masses. More complex transport schemes are allowed by magnetic buoyancy, with larger effects on Li, but most normal LMS seem to show only the range of Li variation discussed here.

We present the identifications of two z ~ 3·8 quasars from a deep UBI imaging survey with the Palomar 5·1 m Telescope. The survey covers an area of 0·25 degree2 around a sample of ten z =0·2–0·3 luminous X-ray clusters. The QSOs were identified on the basis of their stellar morphologies, relatively blue optical and very red UV–optical colours. The two objects are Q 1322+5034, with total magnitudes of B =20·8, I =18·3 and (U–B) > 4·7, and Q 1722+3211, which has total magnitudes of B =21·8, I =19·7 and (U–B) > 3·2. Subsequent spectroscopic observations with the 4·2 m William Herschel Telescope have confirmed the identity of these two sources as QSOs at z =3·82 and z =3·73 respectively. Our spectroscopic observations identify a damped Lyman-α absorber in the spectrum of Q 1322+5034 at z =3·439, as well as a second absorption system at z =2·700, which may be either a single very high column density, damped Lyman-α system, or more likely a blend of a number of high column-density absorbers spread over a distance of ~10 Mpc.

We simulate the chemodynamical evolution of a hundred elliptical galaxies using our GRAPE-SPH code, and succeed in reproducing the radial metallicity gradients and the global scaling relations such as the fundamental plane. These observations cannot be explained by either monolithic collapse or by major merger alone. Rather it requires a model in which both formation processes arise, such as the present CDM scheme.

Results are presented of long-term monitoring at the radio telescope RATAN–600 and a model interpretation of instantaneous 1–22 GHz spectra at six frequencies for a sample of 550 compact extragalactic radio sources. The sources are selected from the Preston et al. (1985) VLBI survey and are located in the declination range from −30° to +43°. Dependence of the index of variability on frequency is analysed for different subsamples. Factors of flux density variations range from 1 to 15. A typical behaviour of spectra evolution during strong radio outbursts in various objects is recognised suggesting a common physical nature of the variability. Invoking VLBI observations in spectra–structure analysis, we find that usually more than 70% of the total emission is coming from the mas scale at frequencies higher than 5 GHz. The observed variability can be explained in the model with a relativistic jet of parsec scale in the longitudinal magnetic field or in the shock-in-jet model.

The DEep Near-Infrared Survey of the southern sky (DENIS) will produce an important by-product: a clean, complete view of the local Universe to z ∼ 0·07 for 105 galaxies. We identify the FLAIR multi-fibre system on the UKST as an extremely competitive facility to undertake follow-up spectroscopy for this sample due to the need to cover wide areas of sky and observe thousands of objects to a relatively bright (B < 17·5) magnitude.

While amongst the most luminous objects in the universe, many details regarding the inner structure of quasars remain unknown. One such area is the mechanism promoting increased polarisation in the broad absorption line troughs of certain quasars. This study shows how microlensing can be used to differentiate between two popular models that explain such polarisation through a realistic computational analysis. By examining a statistical ensemble of correlation data between two observables (namely image brightness and polarisation of the flux coming from the quasar), it was found that through spectropolarimetric monitoring it would be possible to discern between a model with an external scattering region and a model without one.