The high spatial resolution of the Chandra X-ray Observatory allows us to study the environment of GPS/CSS sources to within an arcsec of the strong compact core. We present the discovery of X-ray jets in two GPS quasars, PKS1127–145 and B2 0738+313, indicating that X-ray emission associated with the relativistic plasma is present at large distances from the GPS nucleus. We also discuss first results from Chandra observations of our GPS/CSS sample. We find that six out of ten sources show intrinsic absorption at a level which may be sufficient to confine the GPS source.

Analysis of data from the Rossi X-ray Timing Explorer satellite's All Sky Monitor (ASM) instrument for several X-ray binary sources has identified a recurrent ∼24 h period. This period is sometimes highly significant, giving rise to the possibility of it being identified as an orbital or super-orbital period. Further analysis has revealed the same period in a number of other X-ray sources. As a result this period has been discounted as spurious, described variously as arising from daily variations in background levels, the scheduling of ASM observations and beating between the sampling period and long-term secular trends in the light curves. We present here an analysis of the spurious periods and show that the dominant mechanism is in fact spectral leakage of low-frequency power present in the light curves.

A cloud monitor has been developed for use with cosmic ray air shower fluorescence detectors, the High Resolution Fly's Eye and the Pierre Auger Observatory. This is based on an infrared thermopile device which, unlike previous such monitors, requires no moving chopper and is suitable for unattended operation over long periods of time.

There are many reasons why it is important to increase the number of known pulsars. Not only do pulsar searches continue to improve statistical estimates of, for example, pulsar birthrates, lifetimes and the Galactic distribution, but they continue to turn up interesting and, in some cases, unique individual pulsars. In the early days of pulsar astronomy, the Molonglo radio telescope led the world as a pulsar detection instrument. However, the Parkes radio telescope, with its frequency versatility and greater tracking ablility, combined with sensitive receivers and powerful computer detection algorithms, is now the world’s most successful telescope at finding pulsars. The Parkes multibeam survey, begun in 1997, by itself will come close to doubling the number of known pulsars. Parkes has also been very successful at finding millisecond pulsars (MSPs), especially in globular clusters. One third of the known MSPs have been found in just one cluster, 47 Tucanae.

Digital signal processing is one of many valuable tools for suppressing unwanted signals or inter-ference. Building hardware processing engines seems to be the way to best implement some classes of interference suppression but is, unfortunately, expensive and time-consuming, especially if several miti-gation techniques need to be compared. Simulations can be useful, but are not a substitute for real data. CSIRO’s Australia Telescope National Facility has recently commenced a ‘software radio telescope’ project designed to fill the gap between dedicated hardware processors and pure simulation. In this approach, real telescope data are recorded coherently, then processed offline. This paper summarises the current contents of a freely available database of base band recorded data that can be used to experiment with signal processing solutions. It includes data from the following systems: single dish, multi-feed receiver; single dish with reference antenna; and an array of six 22 m antennas with and without a reference antenna. Astronomical sources such as OH masers, pulsars and continuum sources subject to interfering signals were recorded. The interfering signals include signals from the US Global Positioning System (GPS) and its Russian equivalent (GLONASS), television, microwave links, a low-Earth-orbit satellite, various other transmitters, and signals leaking from local telescope systems with fast clocks. The data are available on compact disk, allowing use in general purpose computers or as input to laboratory hardware prototypes.

Recent advances in the knowledge of the evolutionary status of asymptotic giant branch (AGB) stars and of the nucleosynthesis processes occurring in them are discussed, and used to interpret abundance determinations for s-process elements, lithium and CNO isotopes in several types of AGB stars. We focus our attention mainly on carbon-rich AGB stars. By combining these different constraints we conclude that most carbon stars in the solar neighborhood are of low mass (M≤3 M ⊙), their abundances being a consequence of the operation of thermal pulses and the third dredge-up. However, the observed abundances in carbon stars of the R and J types cannot be explained by this standard scenario. These stars may not be on the AGB, but possibly in the core-He burning phases; their envelopes may have been polluted with nuclear ashes of the core-He flash, followed by CNO re-processing enhancing 13C. Observational evidence suggesting the operation of non-standard mixing mechanisms during the AGB phase is also discussed.

The Monash University Physics Department is constructing a spectrograph, to be attached to a 0·46-m Cassegrainian telescope. To help future users of the spectrograph determine the operational capabilities of the spectrograph a PC-based software package was created. This program allows the user to simulate the response of the spectrograph to various stellar types under differing observational constraints. We have estimated the precision of measurements of stellar radial velocities with the spectrograph. The estimates are reasonable but are yet to be compared with real data.

Starting from a sketch of the s-process concept formulated 50 years ago, the nuclear physics data for s-process calculations are briefly reviewed with emphasis on the status of neutron capture cross sections and beta decay rates. Accurate and comprehensive experimental data are mandatory as direct input for s-process calculations as well as for improving the complementary information from nuclear theory. The current challenges of the field are discussed in the light of new or optimized methods and state-of-the-art facilities, indicating the potential for accurate measurements and the possibility to study cross sections of radioactive isotopes. These opportunities will be considerably enriched by the enormous improvements provided by new facilities.

We present the proceedings from a two-day workshop held at Swinburne University on 2005 May 24–25. The workshop participants highlighted current Australian research on both theoretical and observational aspects of galaxy groups. These proceedings include short one-page summaries of a number of the talks presented at the workshop. The talks presented ranged from reconciling N-body simulations with observations, to the Hı content of galaxies in groups and the existence of ‘dark galaxies’. The formation and existence of ultra-compact dwarfs in groups, and a new supergroup in Eridanus were also discussed.

We review the theory of shock drift acceleration, developing the theory in detail for gyrophaseaveraged particles. It is shown howboth the upstream and downstream velocity spaces separate into different regions according to the interaction of the particles with the shock (reflection, transmission, head-on, overtaking). The effects of the cross-shock electric field and of the magnetic overshoot are discussed. The effectiveness of acceleration is estimated for Maxwellian and power law distributions. The condition for a beam instability to be generated by reflected particles is determined and found to be independent of the distribution function for isotropic inflowing electrons.

We present quasi-simultaneous multi-colour optical/near-IR photometry for 157 radio selected quasars, forming an unbiassed sub-sample of the Parkes Flat-Spectrum Sample. Data are also presented for 12 optically selected QSOs, drawn from the Large Bright QSO Survey. The spectral energy distributions of the radio- and optically-selected sources are quite different. The optically selected QSOs are all very similar: they have blue spectral energy distributions curving downwards at shorter wavelengths. Roughly 90% of the radio-selected quasars have roughly power-law spectral energy distributions, with slopes ranging from F v ∝v 0 to F v ∝v −2. The remaining 10% have spectral energy distributions showing sharp peaks: these are radio galaxies and highly reddened quasars. Four radio sources were not detected down to magnitude limits of H ∼ 19·6. These are probably high redshift (z > 3) galaxies or quasars. We show that the colours of our red quasars lie close to the stellar locus in the optical: they will be hard to identify in surveys such as the Sloan Digital Sky Survey. If near-IR photometry is added, however, the red power-law sources can be clearly separated from the stellar locus: IR surveys such as 2MASS should be capable of finding these sources on the basis of their excess flux in the K-band.

We have performed large-scale nucleosynthesis calculations within the high-entropy-wind (HEW) scenario of Type II supernovae. The primary aim was to constrain the conditions for the production of the classical ‘p-only’ isotopes of the light trans-Fe elements. We find, however, that for electron fractions in the range 0.458 ≤ Y e ≤ 0.478, sizeable abundances of p-, s- and r-process nuclei between 64Zn and 98Ru are coproduced in the HEW at low entropies (S ≤ 100) by a primary charged-particle process after an α-rich freezeout. With the above Y e–S correlation, most of the predicted isotopic abundance ratios within a given element, e.g. 64Zn(p)/70Zn(r) or 92Mo(p)/94Mo(p), as well as of neighboring elements, e.g. 70Ge(s + p)/74Se(p) or 74Se(p)/78Kr(p) agree with the observed Solar-System ratios. Taking the Mo isotopic chain as a particularly challenging example, we show that our HEW model can account for the production of all 7 stable isotopes, from ‘p-only’ 92Mo, via ‘s-only’ 96Mo up to ‘r-only’ 100Mo. Furthermore, our model is able to reproduce the isotopic composition of Mo in presolar SiC X-grains.

X-ray observations of PKS 1934–63 and S5 1946+708 have been made with Beppo SAX lasting 100 and 40 ksec, respectively. Both sources were detected, and in both there is evidence (at 90% confidence) of a strong iron Kα line which would indicate that the nuclei are surrounded by Compton thick material (˜1 g cm−2).

For 1946+708 VLBI H I absorption data are available from the literature. With the condition that free–free absorption should be modest for the source to be observable a minimum radius of around 20 pc is derived for the absorbing torus. The torus is predominantly molecular with a density of 108 cm−3. The corresponding pressure is rather high. Observations with XMM have been requested to verify the large equivalent width of Kα with a better confidence level.

In 1934–63 no important H I absorption was previously detected and no nucleus has been seen in radio data at 8 GHz. If this is due to free–free absorption a molecular torus with a radius less than 5 pc could be responsible. The density would be 108 cm−3 or more.

The relatively low S/N ratio of our observations does not allow a fully convincing conclusion to be reached. But our discussion shows that the combination of X-ray and high resolution 21-cm absorption data can provide important information on the physical parameters in the absorbing ‘torus’.

Paper to appear in full in Astronomy and Astrophysics.

In this review we compare the three existing sets of theoretical yields of zero metal massive stars available in the literature. We also show how each of these three different sets of yields fits the element abundance ratios observed in the extremely metal poor star CD 38°245. We find that, at present, no theoretical set of yields of zero metal massive stars is able to satisfactorily reproduce the elemental ratios [X/Fe] of this star.

We present here a preliminary report and commentary of recently processed observations of Hα emission towards the Magellanic Bridge. These data have been analysed in an attempt to quantify the extent to which the stellar population is capable of reshaping the local ISM. We find that the Hα emission regions are small, weak and sparsely distributed, consistent with a relatively quiescent and inactive ISM where radiative and collisional ionisation is inefficient and sporadic. This suggests that energetic processes at the small scale (i.e. ∼tens of pc) do not dominate the energy balance within the ISM of the Bridge, which therefore hosts a pristine turbulent structure, otherwise inaccessible within our own Galaxy. We find Hα emission that is well correlated with detected 12CO(1–0) line emission (a proxy for molecular hydrogen), as well as other easily identified ring-like Hı features.

The neutron-capture cross sections of 186,187Os have been recently measured at the CERN neutron time-of-flight facility n_TOF for an improved evaluation of the Re/Os cosmo-chronometer. This experimental information was complemented by nuclear model calculations for obtaining the proper astrophysical reaction rates at s-process temperatures. The calculated results and their implications for the determination of the time-duration of nucleosynthesis during galactic chemical evolution is discussed.

We review the evidence that the ultra-compact dwarf (UCD) galaxies we recently discovered in the Fornax Cluster form a new, previously unknown class of galaxies and we discuss possible scenarios for their formation. We then present recent results that UCDs are also present in the Virgo Cluster, and that there is a much larger than expected population of fainter UCDs in the Fornax Cluster. The size and properties of this population may lead us to revise our original ‘galaxy threshing’ hypothesis for the formation of UCDs.

Asymptotic Giant Branch (AGB) stars play a fundamental role in s-process nucleosynthesis during their thermal pulsing phase. The theoretical predictions obtained by AGB models at different masses, s-process efficiencies, dilution factors and initial r-enrichment, are compared with spectroscopic observations of Carbon-Enhanced Metal-Poor stars enriched in s-process elements, CEMP(s), collected from the literature. We discuss here five stars as example, CS 22880-074, CS 22942-019, CS 29526-110, HE 0202-2204 and LP 625-44. All these objects lie on the main sequence or on the giant phase, clearly before the thermally pulsing AGB stage. The hypothesis of mass transfer from an AGB companion, would explain the observed s-process enhancement. CS 29526-110 and LP 625-44 are CEMP(s + r) objects, and are interpreted assuming that the molecular cloud, from which the binary system formed, was already enriched in r-process elements by SNII pollution. In several cases, the observed s-process distribution may be accounted for by AGB models of different initial masses with proper 13C-pocket efficiencies and dilution factors. Na (and Mg), produced via the neutron capture chain starting from 22Ne, may provide an indicator of the initial AGB mass.

Astro Concepts is a project within Swinburne University of Technology in Melbourne developing browser-based software modules on Optical Telescopes, Nebulae and Binary Stars. The modules are designed to enhance students' understanding of basic physics concepts, which underlie introductory-level conceptual astronomy courses. When complete, the Astro Concepts modules will be available for use in university courses in introductory astronomy, introductory physics teaching, secondary teaching and online astronomy education. The strategy outlined here is to obtain a reasonable level of understanding of the necessary physics concepts by presenting them embedded in relevant and interesting astronomy contexts, and by the use of an engaging educational approach requiring active learning by the student.

We study the contents of an apparent void in the distribution of Lyα emitting galaxies at redshift 2.38. We show that this void is not empty, but contains a damped Lyα absorption-line system, seen in absorption against background QSO 2138-4427. Imaging does not reveal any galaxy associated with this absorption-line system, but it contains metals (Fe/H ∼ −1.3), and its large velocity range (∼180 km s−1) implies a significant mass.