bluuebunny/crossref_metadata_2025 huggingface dataset:
Alignment of Southern Radio Sources
Authors: White Graeme L. , McAdam W. B. , Jones I. G.
Published: July 2016

The alignment of galaxies within clusters and superclusters may be sought either in the major axis of the observed optical distribution or in any radio or X-ray structure from an active nucleus.
Supernova Remnant Searches at Molonglo
Authors: Turtle A. J. , Mills B. Y.
Published: July 2016

A catalogue of 38 supernova remnants (SNRs) identified in the Large and Small Magellanic Clouds from X-ray, optical and radio observations has recently been presented by Mills et al. (1984). One important consideration is the completeness of this catalogue and of the Galactic catalogues with which it is compared. These are currently being investigated.
Synthetic OH Band Spectra in G and K Stars
Authors: Bessell M. S. , Hughes S. M. G. , Cottrell P. L.
Published: July 2016

Carbon, nitrogen and oxygen are of interest for stellar and galactic evolution for four main reasons. Firstly, they comprise most of the mass of elements heavier than helium, so their abundance reflects the bulk of chemical enrichment. Secondly, all of the oxygen, much of the carbon and perhaps some of the nitrogen is believed to be produced in shorter-lived stars more massive than those responsible for the Fe production (Tinsley 1979), so their abundance relative to Fe in very metal deficient objects should provide key information for modelling the chemical history of galaxies. Thirdly, because C and O comprise the bulk of the metals in stellar material (Fe:C:N:0 = 1:12:2.5:21 in the Sun) it is their abundance as well as that of iron, which is needed to compute evolutionary tracks for different metallicities. Finally, the O abundance will indicate whether CNO material has been mixed to the surface.
The Molonglo Observatory Transient Event Recorder
Authors: Large M. I. , Vaughan A. E. , Durdin J. M. , Little A. G.
Published: July 2016

In its normal synthesis mode of operation, the Molonglo Observatory Synthesis Telescope (MOST) tracks a region of sky for a period of 12 hours with 64 real-time fan beams having high sensitivity at 843 MHz (Mills 1981). It thus provides an excellent opportunity to monitor the sky at the same time for transient radio events. During a 12 hour synthesis observation the fan beams rotate 180° on the field. Thus any sources producing occasional radio transients can be located by analysing the positions of the beams on which the events are recorded. Futhermore, by rejecting events which occur simultaneously on non-adjacent beams, local terrestrial sources of impulsive interference may be eliminated. This technique for recognizing extra-terrestrial sources was of considerable value in the first Molonglo pulsar search when only two beams were used.
Cosmic Ray Intensity Waves and the North-South Anisotropy
Authors: Jacklyn R. M. , Duldig M. L. , Pomerantz M. A.
Published: July 2016

Waves of variation in the daily average cosmic ray intensity at the Earth’s surface were first detected in the neutron monitor record. Following the abnormal cosmic ray storm of September 1978, a sinusoidal 13.5 day periodicity was observed in the average intensity (Pomerantz and Duggal 1979), persisting for at least two solar rotations. Further observations, including underground data from the southern hemisphere, confirmed that not only were the waves isotropic but exhibited approximately a p−1 variational dependence on primary rigidity p (Duggal et al. 1981). No further evidence for this kind of wave has yet come to light. However, in the latter half of 1982 a series of 27-day waves that were apparently of a different character were detected. The evidence for their presence resulted from an analysis of the disturbed period that followed the occurrence of the large Forbush Decrease commencing 13 July 1982. It seemed at first that they could be described as anisotropic waves of the well-known interplanetary North-South asymmetry (Jacklyn and Pomerantz 1983).
The Cosmic Ray Solar Flare Increase of 16 February 1984
Authors: Fenton A. G. , Fenton K. B. , Humble J. E.
Published: July 2016

Six solar proton events have been observed by ground level cosmic ray detectors so far during solar cycle 21, a little less than one per year. All of these have been much smaller than the giant events observed in solar cycle 19. As with many other aspects of solar activity, the reason for the differences from cycle to cycle remain unknown.
A New Estlmate of the Hubble Constant Using the Virgo Cluster Distance
Authors: Visvanathan N.
Published: July 2016

A new distance modulus (31.23) to the Virgo cluster is derived using the distances to nearby galaxies given by Sandage and Tammann, de Vaucouleurs, ourselves and DDO observers. This when combined with the undisturbed mean Virgo cluster velocity 1182 km s-1, gives a value for the global Hubble constant as 67 ±4 km s-1Mpc-1.
Middle Infrared SpectropolarJmetry of Eta Carinae.
Authors: Briggs G. P. , Aitken D. K.
Published: July 2016

Spectropolarimetric observations of the 10 arc second region surrounding Eta Carinae have been made in the 8-13 μm wavelength band. The observed polarization, of a few percent, is due to emission of radiation from aligned grains. The radial position angle of the polarization suggests that gas streaming is responsible for the grain alignment.
A Search of Steep-Spectrum Radio Sources for Millisecond Pulsars
Authors: D’Amico N. , Manchester R. N. , Manchester R. N. , Durdin J. M. , Erickson W. C.
Published: July 2016

A total of 18 radio sources selected on the basis of steep low-frequency radio spectra have been searched for the presence of millisecond pulsars using the Molonglo Observatory synthesis telescope. The search covered pulsar periods down to 2 ms with a limiting sensitivity of approximately 10 mJy. No pulsars were detected.
A Drag Dominated Model of the Magellanic Stream
Authors: Meurer Gerhardt R. , Bicknell G. V. , Gingold R. A.
Published: July 2016

We present here the best of a series of models of the Magellanic stream. The dominant force in these models is gas drag. Gaseous cloudlets are torn from the bridge between the Large and Small Magellanic Clouds as the Magellanic system passes through a hot gaseous halo about our galaxy. The cloudlets are then stretched apart from each other by tidal and drag forces to form the Magellanic stream. Our best model closely reproduces the position of the stream on the sky and the run of radial velocities along the Magellanic stream. The agreement is almost as good as the best purely tidal model. In our best model the Magellanic system is only loosely bound to our galaxy and is on the first encounter with it. This overcomes some of the problems with purely tidal models. Our series of models indicate that there is a wide range of parameters that will produce a reasonable stream under the forces of gas drag and gravity.
On the Relationship between Lenses and Inner Rings in Spiral Galaxies
Authors: Schwarz M. P.
Published: July 2016

In simulations of gas flow in the gravitational field of model barred galaxies which we have described elsewhere, structures resembling inner rings have formed. The model rings encircle the bar as observed in real galaxies, but are more elongated than the average inner ring. In this paper we show that the addition of a lens-like component to the background field results in much rounder rings. Indeed the shape and position of the model rings are very sensitive to any steep gradients in the azimuthally averaged surface density near the ends of the bar.
A Method of Calculating Radiative Heat Diffusion in Particle Simulations
Authors: Brookshaw L.
Published: July 2016

A new method for solving heat diffusion in three dimensional particle simulations is described. The difficulties encounted by other authors is discussed, in particular the difficulty of including boundary conditions in particle simulations. One and three dimensional tests of the method are described.
Astronomy on Ice
Authors: Pomerantz Martin A.
Published: July 2016

The geographic South Pole, where the United States maintains a year-round scientific station, affords a number of unique advantages for certain types of astronomical observations. These include: continuous viewing and constant declination of ail objects in the southern celestial hemisphere, exceedingly low humidity, extended periods of coronal seeing, high altitude, and uniform terrain. The areas of research that have already benefited immensely from thèse extraordinary features are helioseismology and submillimeter astronomy. Unparalleled observations of global solar oscillations have already yielded significant information about the structure and dynamics of the Sun’s interior. Far infrared measurements of various galactic and extra-galactic regions have attained an unprecedented level of sensitivity, limited for the first time only by the noise inherent in the detector. In addition to further helioseismological observations, currently planned future activities include observational cosmology and ultra high energy gamma ray astronomy.
Features of the Chandlerian Nutation
Authors: Abraham H. J. M.
Published: July 2016

Reported data on the Chandlerian nutation show that there are irregular yet related changes in the rate of energy gain, the damping and the phase, changes which were remarkably great in the late 1920s. Dynamical interpretations need a model that has friction elements as well as springs and dashpots; it then offers further applications as well; e.g. to a correlation between reported values of the Love number k and tidal potentials. The model is used in discussing the increases in amplitude and the advances in phase; the short and long-term rates of energy gain and their interruptions and damping; the correlation between short Chandlerian periods and large amplitudes in the annual nutation; and the correlation between damping and the apparent frequency. Doubts are expressed about nutational values of Q. A geophysical interpretation of the model is obtained from seismic data. It was found that every large rise in the nutational energy was preceded by an earthquake in the Andes region; and that the secular rate of energy gain varied with the circum-Pacific seismicity. Decreases in these were accompanied by rises in the Earth’s rotational acceleration and were followed by deep earthquakes in a diminishing region east of the Andes. It appears that the nutational and seismic events are due to tectonic stress, and intermittently this is relieved by subduction.
Galactic Cosmic Ray Anisotropies in the Energy Range 1011 – 1014eV.
Authors: Jacklyn R.M.
Published: July 2016

A review is presented of the evidence for anisotropies of galactic origin in the charged cosmic ray particle intensity at median primary energies of detection in the range 1011 – 1014eV. It concerns the period from 1958, when the first substantial long-term observations at energies of solar and sidereal modulation near 1011eV commenced underground, until 1984, by which time results were available from a number of years of accurate observations with detectors of small air showers at energies near 1014eV, too high for complicating effects of solar origin to be present. There is evidence for the existence of both unidirectional and bidirectional galactic anisotropies over the whole energy range. Tentative descriptive models are discussed in relation to advances both in solar and sidereal analytical techniques and in the ability of experimenters to account for and exploit the modulating influence of the heliomagnetosphere at the lower energies of detection.
Are There Many More Small Meteors Than Hitherto Detected?
Authors: Olsson-Steel D. I. , Elford W. G.
Published: July 2016

Visual meteors, due to impinging meteoroids of radius about 1 cm, appear at a rate of a few per hour during non-shower periods. Smaller meteoroids (100 μm – 1 cm) give rise to less bright trails, but are much more abundant. These are usually detected by radars of about 10 m wavelength which, over the past 40 years, have produced a plethora of information concerning mass and height distributions, orbits, etc.

Using such ‘conventional radars’, the peak of the measured height distribution is found at about 95 km, with few meteors detected above 105 km. However, the flux detected is only a few percent of the total flux (a) measured using a large (10 m) optical collector, and (b) expected from a comparison with measurements by satellite impacts and zodiacal light observations (radii < 100 μm). One possibility is that the radars detect few low-velocity (V < ~25 km s-1) meteors since these produce little ionization and thus limit their detectability: the ionizing efficiency of meteors varies as ~ V7/2. In direct opposition, our alternative hypothesis is that the undetected flux is held in a faint high-velocity component which ablates at high altitude. These are not detected by conventional radars because meteor trails have ‘initial widths’ of about 3 m at 105 km; for a radar wavelength of 10 m, components scattered from different regions of the trail therefore destructively interfere, and the probability of detecting any meteor above 105 km is small.

In order to test our hypothesis we have measured the height distribution with a 150 m radar, and we are commencing ancillary observations at 50 m; compared to these wavelengths the initial width is small to at least 140 km. The results show a peak at 105 km with most meteors being above this, significant numbers occurring right up to 140 km. This suggests that the true flux is at least 10 or 20 times that previously deduced, having implications for the number of cornets in the recent past and the balance of material between the smaller bodies in the solar System.
The Kinematics and Age of the Planetary Nebulae in the Large Magellanic Cloud
Authors: Meatheringham Stephen J. , Dopita Michael A.
Published: July 2016

An HI survey of the Large Magellanic Cloud (LMC) has been reanalyzed to find the transverse velocity of the LMC, and derive an upper limit of 4.5 × 1011M⊙for the mass of our Galaxy out to 50 kpc. A rotation curve is derived for the LMC from the HI data giving a best mass estimate of (4.0±0.4)×109M⊙. Velocity observations of 97 planetary nebulae (PN) in the Large Cloud are used to compare the old and young components. Our results are found to be at odds with an earlier sample of 9 old clusters, which is interpreted as being due to the low number of objects in that sample. The w-component of velocity dispersion of the PN population is 35 km s-1and that of the HI 10 km s-1. If this difference is a result of stellar diffusion then the average age of the PN population is 1.3 × 109yr, implying a precursor mass of 1.8 M⊙and a remnant mass of 0.63 M⊙.
Corrected Formula for the Polarization of Second Harmonic Plasma Emission
Authors: Melrose D. B. , Dulk G. A. , Gary D. E.
Published: July 2016

Second harmonic plasma emission is attributed to the coalescence of two Langmuir waves into a transverse wave.
On the Longitudinal Distribution of Solar Type II Bursts
Authors: Wright C. S.
Published: July 2016

Distributions in longitude of solar radio bursts often are compiled by identifiying the position of the burst with the position of the associated H-Alpha flare. Early work on the longitudinal distribution of type II bursts compiled in this way (eg. Maxwell and Thompson 1962) indicated an approximately uniform distribution. Subsequently Svestka and Fritzova — Svestkova (1974) and Svestka (1976) published a distribution of 244 H-Alpha flares with which type II bursts were associated (hereafter called type II flares) that showed marked deficits near central meridian and the limb (Fig. 1). They suggested that the distribution was a product of propagational selection, being in some way dependant on the nature of the type II source mechanism as well as the manner by which the radiation reached the observer. On this basis they argued that the number of type II bursts that occurred near central meridian and near the limb was underestimated.
Planetary Observations with the Tidbinbilla Interferometer
Authors: Batty M. J. , Jauncey David L. , Rayner P. T. , Gulkis S.
Published: July 2016

Radio measurements of the outer planets at wavelengths longer than ~ 10 cm are difficult: the emission is weak (generally following an optically thick thermal spectrum — i.e. S ∝ λ-2) and the confusion due to background sources may be large.
A Polarization Model for 12 Lacertae
Authors: Stamford P. A. , Watson R. D.
Published: July 2016

Recent evidence suggests that radial pulsation can explain most of the variability in the majority of well-studied β Cephei stars (Stamford and Watson 1978; Campos and Smith 1980).
Infrared Studies of the Young Stellar Population of 30 Doradus
Authors: McGregor P. J. , Hyland A. R.
Published: July 2016

The 30 Doradus region offers an excellent opportunity to study cluster formation processes and recent star formation in the Large Magellanic Cloud.
Australia and the Transit of Venus
Authors: Bray R. J.
Published: July 2016

The passage of the planet Venus across the face of the Sun is an astronomical spectacle which no living person is likely to have seen. The phenomenon has played an important role in the history of astronomy and in stimulating world science and geographical discovery during the 18th century. But to Australia the transit of 1769 is of truly momentous significance: during the course of an expedition to the South Seas specially organized to observe it, Lt. James Cook discovered and chartered the east coast of Australia, hoisted the English flag, and took possession in the name of King George III.
Progress in Galaxy Redshift Surveys using FLAIR
Authors: Watson F. G. , Broadbent A. , Hale-Sutton D. , Shanks T. , Parker Q. A. , Oates A. P.
Published: July 2016

Among the most important stimuli for developing the FLAIR multi-object spectroscopy system on the 1.2-m UK Schmidt Telescope was its potential for carrying out large-scale redshift surveys of galaxies of intermediate magnitude (B <~ 17). During FLAIR’s lengthy development period, these objects provided the yardstick by which the system’s performance was measured, and a number of limited-area redshift surveys were carried out. We are now following these with a 1-in-3 survey over the 60 fields of the ROE/Durham Galaxy Catalogue to produce a redshift map of some 4000 galaxies out to a distance of ~ 300h−1 Mpc (where the parameter h is the Hubble constant expressed as a fraction of 100 kms−1 Mpc−1). In this paper we summarise the results from our redshift surveys to highlight the capabilities of FLAIR. We present a status report on the current large-scale survey, and show that the recently-introduced FLAIR II system will speed its progress considerably.
The Galactic Plane Radio Source G321.48 + 1.02: is it Extragalactic?
Authors: Caswell J. L. , Stewart R. T.
Published: July 2016

strong non-thermal radio sources at low galactic latitude may be young galactic supernova remnants or else distant extragalactic objects located in the direction of the galactic plane merely by chance. Here, we have imaged G321.48 + 1.02 with the Australia Telescope in order to distinguish between these alternatives for this source.
A Second Compact Radio Component Detected in the LMC HII Region N159
Authors: Hunt M. R. , Whiteoak J. B.
Published: July 2016

The Australia Telescope Compact Array has been used for observations, with arcsecond resolution, of the HII region N159 in the Large Magellanic Cloud. Images at 5 GHz reveal a second compact continuum component which has no obvious counterpart at optical and infrared wavelengths. Observations of HI 10α recombination-line emission, and HI and H2CO absorption, suggest that the object is a compact HII region embedded in a dense obscuring cloud on the edge of N159.
Reconstruction of the Annual Variation in Solar Radio Flux and the Catania Sunspot Area from Tree Ring-index Time Series
Authors: Murphy J. O. , Sampson H. , Veblen T. T. , Villalba R.
Published: July 2016

Four tree ring-index site chronologies, representing standardised annual growth rates for spruce trees growing at high altitude sites in Colorado, have been employed as proxy data in a regression model for the annual variation of solar radio flux at 2800 MHz (F10·7) and the Catania sunspot area (Ac). These dendrochronological time series all exhibit significant power spectrum peaks at about 11 years and separately correlate with the annual values of Rz, F10·7 and Ac, as solar activity indicators. The two models constructed give the cyclic variation of F10·7 and Ac back to AD1673.
The Population I Core of the Galaxy
Authors: Allen David , Burton Michael
Published: July 2016

We demonstrate the presence of a cluster of hot, population I stars at the very centre of the Galaxy, using the depth of the first overtone band of CO and the presence of emission in He I 2 ·058 μm and [Fell] 1·644μm to identify stars. The cluster is very compact and comprises at least several hundred stars. They lie close to the nonthermal radio source Sgr A* and dominate the luminosity and mass loss of the Galactic core. Their presence suggests that a starburst occurred at the Galactic centre.
Adaptive Optics at the Anglo-Australian Telescope
Authors: O’Byrne J. W. , Bryant J. J. , Minard R. A. , Fekete P. W. , Cram L. E.
Published: July 2016

A consortium of Australian universities and the Anglo-Australian Observatory is currently implementing an adaptive optical system at the Anglo-Australian Telescope. This project aims to enhance the science output of the telescope and establish the utility of adaptive optics at the AAT site. The first stage of the project is a fast tip-tilt system, described here, to be installed in the west coudé room. Subsequent funding has been obtained to implement a second-stage, low-order deformable mirror system which is also outlined. Both phases will primarily serve the IRIS camera/spectrograph, since the maximum gains in image quality will occur in the infrared.
Dust Obscuration in the Universe
Authors: Masci F. J. , Webster R. L.
Published: July 2016

A substantial population of red quasars has been discovered in a complete sample of flat-spectrum radio sources. Dust is the most likely cause of the reddening in this sample. The location of the dust is poorly known, but may either be in the line-of-sight to the quasar, or in the immediate quasar environment. In this paper we are interested in models where the dust is located in the line of sight to the quasar. We calculate the probability distribution of the optical depth in galactic dust as a function of source redshift, using a range of parameters which might describe real galaxies. We compare these results with those found for our sample of radio quasars. If the dust content is unevolving, then it is not possible to account for all the observed reddening in the quasar sample using these models. Our minimum dust model predicts that 15% of background quasars to z ~ 5 will have a line of sight within 5 kpc of a galaxy’s centre, and would therefore be reddened out of B-band flux-limited samples.
Instrumentation Plans at the AAO: 2dF and Beyond
Authors: Cannon Russell
Published: July 2016

This paper is based on a report given at the ASA Conference in July 1994, but takes account of subsequent developments up to the end of the year. The present state of the Two-degree Field (2dF) project for the AAT is reported. Good progress is being made on all fronts but some slippage has occurred, so that the instrument is now expected to begin astronomical observations only during the second half of 1995. An outline of other current and future instrumentation plans at the AAO is given.
A Hartmann Differential Image Motion Monitor (H-DIMM) for Atmospheric Turbulence Characterisation
Authors: Bally John , Theil David , Billawala Youssef , Potter Dan , Loewenstein R. F. , Mrozek Fred , Lloyd James P.
Published: July 2016

We describe the use of a multi-aperture Hartmann mask coupled to a slightly out-of-focus focal plane array imager to monitor atmospheric turbulence (‘seeing’) produced by refractive index fluctuations. The imager (a CCD) is located inside or outside the focal surface of the imaging system so that each sub-aperture of the Hartmann mask produces an image well separated from all of the other images produced by the mask. Since the depth of focus of the sub-apertures is an order of magnitude larger than that of the parent optical system, the individual images are still diffraction-limited. We obtain short (10 to 100 msec) exposures and monitor the position fluctuations of the images. Analysis of the position and intensity fluctuations of the images can be used to determine the atmospheric parameter r0, the wind direction and velocity, and, under some circumstances, the distance of the turbulent layer from the observing site.
A Study of the Stability Properties of Smooth Particle Hydrodynamics
Authors: Morris Joseph Peter
Published: July 2016

When using a formulation of smooth particle hydrodynamics (SPH) which conserves momentum exactly the motion of the particles is observed to be unstable to negative stress. It is also found that under normal circumstances a lattice of SPH particles is potentially unstable to transverse waves. This paper is a summary of a detailed report (Morris 1994) investigating the nature of these and other instabilities in depth. Approaches which may be used to eliminate these instabilities are suggested. It is found that the stability properties of SPH in general improve as higher-order spline interpolants, approximating a Gaussian, are used as kernels.
Millimetre Observations of Evolved Stars
Authors: Chapman Jessica M.
Published: July 2016

Radio emission at centimetre and millimetre wavelengths provides a powerful tool for studying the circumstellar envelopes of evolved stars. These include stars on the asymptotic giant branch (AGB), post-AGB stars and a small number of massive M-type supergiant stars. The AGB stars and M-type supergiants are characterised by extremely high mass-loss rates. The mass loss in such an evolved star is driven by radiation pressure acting on grains which form in the outer stellar atmosphere. The grains are accelerated outwards and transfer momentum to the gas through grain–gas collisions. The outflowing dust and gas thus form an expanding circumstellar envelope through which matter flows from the star to the interstellar medium, at a typical velocity of 15 km s−1. For a recent review of circumstellar mass loss see Chapman, Habing & Killeen (1995).
The Continuum Slopes of Optically Selected QSOs
Authors: Francis Paul J.
Published: July 2016

Quasi-simultaneous optical/near-IR photometry is presented for a sample of 37 luminous optically selected QSOs drawn from the Large Bright QSO Survey. Most of the QSOs have decreased in brightness since discovery; this is expected in flux-limited samples. The continuum shape of most of the QSOs can be represented by a power law of the form F(v) ∝ v−0·3, but a few have softer (redder) continuum slopes.
Prospects for the Detection of Gravity Wave Bursts
Authors: Edwards C.
Published: July 2016

Many excellent reviews of gravitational wave astronomy have appeared in the literature (see for example Thorne 1980 and references cited there). Much has also been written on the potential of the second generation of Weber-bar detectors which, operating at low temperatures and exploiting superconducting technology, have design sensitivities up to a million times greater than those of a decade ago. Indeed such has been the intensity of activity in this area, that even before this generation of cryogenic detectors has come of age, a third generation, quantum mechanical in outlook, is already being conceived.
On the Fundamental and Harmonic Components of Low-Frequency Type III Solar Radio Bursts
Authors: Suzuki S. , Sheridan K.V.
Published: July 2016

Ground-based observations of Type III bursts made with spectrographs and spectro-polarimeters, at frequencies above the ionospheric cut-off, reveal that most bursts (excluding storm Type IIIs) have fundamental (F) and harmonic (H) structure (Wild et al. 1959; Dulk and Suzuki 1980). An example of F-H bursts is given by Sheridan (1978). Such bursts are produced by streams of electrons travelling along open magnetic field lines and exciting plasma oscillations which are converted to electro-magnetic waves at both the F and H frequencies of the local plasma frequency in the corona.
Investigation of the Outer Regions of the Galactic Halo
Authors: Ratnatunga Kavan U.
Published: July 2016

The aim of this study is to investigate the spheroidal halo around our Galaxy, that is, the outer extentions of the central bulge. The kinematics and variations in metal abundance in the halo are important astrophysical parameters for any theory which models the formation and evolution of our galaxy. Attempts to determine these parameters have so far used a particular class of stars which can be easily identified as members of the halo.
The Corona Australis Dark Cloud
Authors: Vaile R. A. , Taylor K. N. R.
Published: July 2016

The Corona Australis cometary globule is a large southern object known to be a region of slow star formation. We have mapped the complex in the 21cm hydrogen line and preliminary results are reported in Llewellyn et al. (1981) and Taylor et al. (1981). The most extensive A, map of the region is given by Rossano (1978) and is based on star counts.
Uniformity of UKSTU Photographic Plates
Authors: Dawe J. A. , Metcalfe N.
Published: July 2016

Most plates taken with the UK Schmidt Telescope are hypersensitized before use. The technique for the hyper-sensitization of IIIa-type emulsions has been described by Sim et al. (1976), and for the IV-N emulsion by Hartley and Tritton (1979). Photographic calibration is provided by two sensitometers, a seven-step linear array at the N-W corner and a 4 × 4 spot array in the S-E. During the calibration of this latter sensitometer (Dawe and Metcalfe 1981), which is a copy of a design by Schoening (1976), it became apparent that the sensitivity of the hypersensitized IIIa-emulsions in use was decreasing as a function of time in the plateholder.
Fibre Optic Development at the AAO
Authors: Gray P. M. , Phillips M. M. , Turtle A. J. , Ellis R.
Published: July 2016

Work on the development and use of optical fibres as light guides in astronomical spectroscopy has been underway at the AAO for over a year now. The fibres used are step-index polymer-clad silica with a core size of 200 microns giving an aperture size of 1.3 arcsec at the AAT f/8 focus. They are optimised for data transmission with losses below 5dB/km at a wavelength of 800 nm. The blue transmission is somewhat lower, typically 500dB/km at 300nm and 90dB/km at 400nm but over the short 2m length used these attenuations give transmissions of 79% and 96% respectively.
An Atlas of QSO Spectra
Authors: Wilkes Belinda J. , Wright Alan E. , Jauncey David L. , Peterson Bruce A.
Published: July 2016

We present here the low-dispersion optical spectra of 295 QSO candidates. The great majority of the objects were originally selected as QSOs from the Parkes 2700 MHz radio survey, although we have also included spectra of several optically selected QSOs. A few of the QSO candidates are now better described as radio galaxies and BL Lac objects. This collection of spectra is not suitable for statistical studies unless due consideration is given to selection effects.
Radio Data on Clusters of Galaxies from the Culgoora Circular Array
Authors: Slee O. B. , Siegman Betty C.
Published: July 2016

The Culgoora circular array (CCA) is a 3-km-diameter ring of 96 reflectors operating at 80, 160 and 327 MHz. It has an effective collecting area of ~ 6000 m2 and achieves angular resolutions (full half-power beamwidths) of 3’.70, 1 ‘.85 and 0’.92 at the three operating frequencies. During the interval 1978-1981 we have used the CCA to make 80 and 160 MHz measurements of a comprehensive selection of radio sources which were detected during various complete surveys of clusters of galaxies (see Table 1). We have combined our low-frequency intensity measurements with other available higher-frequency flux data to compute accurate radio spectra. The 160 MHz contour maps for many of the cluster fields were used to find positions and angular sizes for the associated radio sources.
Splitting of the Jupiter S Bursts
Authors: Ellis G. R. A.
Published: July 2016

Spectrum analysis of video tapes of the Jupiter S bursts in the frequency range 8-24 MHz with a frequency resolution of 2 kHz and a time resolution of 0.5 ms has shown that many of the bursts with instantaneous bandwidths less than about 10 kHz and which appear single with lower resolution, are actually double in the frequency-time plane. The frequency interval between the two components varied from 6 kHz at 9 MHz to 10.5 kHz at 23 MHz, and the corresponding time intervals from 1.3 msec to 0.6 ms.
Outstanding Stellar Microwave Flares in 1986
Authors: Slee O. B. , Nelson G. J. , Stewart R. T. , Wright Alan E. , Jauncey David L. , Vaughan A. E. , Large M. I. , Bunton J. D. , Peters W. L. , Ryan S. G.
Published: July 2016

We describe bright microwave events that were first detected with the Parkes 64-m telescope at 8.4 or 22 GHz from six active-chromosphere stars. In some flares spectral data were obtained over a large frequency range from simultaneous measurements with the Parkes reflector (8.4 or 22 GHz), the Tidbinbilla interferometer (8.4 and 2.29 GHz), the Fleurs synthesis telescope (1.42 GHz) and the Molonglo Observatory synthesis telescope (0.843 GHz). Data on circular polarization were obtained from the Parkes observations at 8.4 GHz.

The stars were in a wide variety of evolutionary states, ranging from a single pre-main-sequence star (HD 36705), two RS CVn binaries (HD 127535, HD 128171), an Algol (HD 132742) and two apparently single K giants (HD 32918 and HD 196818). Their high brightness temperatures, positive spectral indices and low polarization are consistent with optically thick gyrosynchrotron emission from mildly relativistic electrons with average energies 0.5 to 3 MeV gyrating in inhomogeneous magnetic fields of 5 to 100 G.
Accurate Strömgren u & y (continuum) photometry of LMC supernova 1987a
Authors: Shobbrook R. R.
Published: July 2016

Continuum photometry of high accuracy with Strömgren u and y filters was used to observe the LMC supernova 1987a for a period of 7 days just two weeks after the outburst.
VLA Observations of NGC 5793
Authors: Whiteoak J. B. , Gardner F. F.
Published: July 2016

The edge-on spiral galaxy NGC 5793 has been observed at frequencies of 4860 and 14940 MHz with the Very Large Array. The corresponding half-intensity beamwidths in the final maps were 0.65 × 0.40 and 0.19 × 0.11 arcsec2. The maps show a continuum source close to the optical nucleus with dimensions of ≤0.01 and 0.04 arcsec in right ascension and declination. The average spectral index is –0.6.
The beginnings of radio astronomy in Australia
Authors: Wild J. P.
Published: July 2016

My lecture this evening is dedicated to my late friend and fellow astronomer, Harley Wood, who died on 26 June 1984 at the age of 72. It is a fine thing that the ASA has decided to give the name of Harley Wood to an annual public lecture at the time of the society’s Annual General Meeting. For besides making a monumental contribution to the astrometry of the southern skies, Harley became a leader, a kind of organizer and father figure, among Australian astronomers. He played a leading part in the formation of this society and was its foundation President. He will also be specially remembered by a small group of us, about half a dozen, who met regularly in the charming old building of Sydney Observatory to plan the 1973 IAU General Assembly held in Sydney, the first time ever in Australia. Harley chaired not only the local organizing committee, but the ladies’ committee too. My wife still recalls the gentle, but firm way in which Harley once admonished her for addressing a remark across the table without going through the Chair. Harley was totally approachable and totally positive at all times: you could always count on his support for any sensible initiative. He had many friends and no enemies that I have heard of. And unlike so many of his profession, there was no hint of the egotist or the prima donna. I count it a privilege to have been his contemporary and colleague.
On Solar Neutrinos and Chemically Inhomogeneous Solar Models
Authors: Robinson S. J.
Published: July 2016

Work is in progress on the extension of a detailed stellar structure code to explore a suggested solution to the Solar Neutrino Problem where the Sun has a small (∼0.01M⊙) high-Z core on entry to the ZAMS. A basic premise of such models is that the core will burn itself out by solar age and the model acquire a neutrino luminosity in line with that observed. The work to date has involved the construction of a standard solar model and, currently, the development of inhomogeneous models with associated adjustments to the structure equations.
LYMAN : A New Window on the Universe
Authors: Dopita M.A. , Tuohy I.R. , Cropper M. , Hunstead R.W. , Lewis B. , Mathewson D.S. , Mitchell C.J. , Norris R.P. , O’Mara J. , Pettini M. , Roberts E.R. , Waterworth M.D.
Published: July 2016

This document is the final Phase A Science Report of the Australian LYMAN Science Working Group, and describes in detail the scientific objectives, technical feasibility, and engineering implementation of the LYMAN mission as developed in the Australian studies.
SN 1987A: the Light Curve
Authors: Menzies J.W.
Published: July 2016

The extensive body of broad-band photometric data for SN 1987A obtained at SAAO has been used to derive the bolometric light curve up to day 450 after the outburst. The salient features of the curve are discussed in this paper.
Optical and Infrared Observations of SN 1987A from Cerro Tololo
Authors: Terndrup D.M. , Elias J.H. , Gregory B. , Heathcote S.R. , Phillips M.M. , Suntzeff N.B. , Williams R.E.
Published: July 2016

Results from optical and infrared observations of SN 1987A obtained at Cerro Tololo Inter-American Observatory since maximum light (100-400 days after core collapse) are reviewed.
Optical spectroscopy of SN 1987A
Authors: Hearnshaw J.B. , McIntyre V.J.
Published: July 2016

Mt John Observatory photographic spectra of SN 1987A have been obtained on 111 nights during the first year at resolutions of 1.1 Å (blue) and 1.6 Å (red). The early spectra are dominated by broad P Cygni profiles from neutral or singly ionised species. Ba absorption lines may be present. After six months nebular emission features emerged, including [OI] 630, 636 nm and two unidentified UV lines (367, 375 nm) in the previously dark region below 380 nm. Absorption line radial velocities show steep declines in the first month, but are almost constant or only slowly decline after 100 days. For the Hα absorption minimum the initial decline rate was 690 ± 70 km s−1d−1 and the initial velocity was −20.2±0.5 Mm s−1 (LMC frame). By 1988 Feb the slowest material in absorption was at −2.2 Mm s−1.

The emission maxima of Hα and NaID show anomalous redshifts of about 1.0 Mm s−1. The [OI] lines show no such redshift. Recent [OI] and Hα spectra at higher resolution show ‘fine structure’ in the profiles, indicating inhomogeneity in the ejecta. Hβ, Hγ and Hδ (but not Hα) were all weaker or absent from 1987 late March to early May, but strong thereafter. From about 1987 Mar 18 to Apr 17 Hα showed a bump on the blue side of the emission at 647 nm and a double peak (658 and 668 nm). Absorption bumps in the Hα profile in early spectra (1987 Feb) may be due to circumstellar water vapour.
Late Evolution of SN 1987A
Authors: Chevalier Roger A.
Published: July 2016

SN 1987A has illuminated a great diversity of astrophysical processes – from neutrino emission during core collapse to the structure of the interstellar medium on a scale of hundreds of parsecs. Here I cover the evolution of SN 1987A from the outside in; the topics are interstellar light echoes, circumstellar light echoes, circumstellar shock waves, late emission and structure of the ejecta, and the effects of a central neutron star.
Extensions to the Coupling Coefficient Calculations for Muon Telescopes
Authors: Baker C. P. , Duldig M. L. , Humble J. E.
Published: July 2016

The calculation of coupling coefficients for muon telescopes has previously used interpolation from a limited set of asymptotic directions of arrival of primary particles. Furthermore, these calculations have not incorporated curvature of the atmosphere and thus diverge from the true response at zenith angles greater than about 75 degrees. The necessary extensions to calculate coupling coefficients at arbitrary zenith angles are given, including an improved method of incorporating the asymptotic directions of the primary particles. It is shown, using this method, that certain coupling coefficients are highly sensitive to small changes in asymptotic directions for some telescope configurations.
Stellar Outflows and Jets
Authors: Zealey W. J. , Mundt R. , Ray T. P. , Sandell G. , Geballe T. , Taylor K. N. R. , Williams P. M. , Zinnecker H.
Published: July 2016

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.
Optical Aperture Synthesis with the Anglo-Australian Telescope
Authors: Bedding T. R. , Robertson J. G.
Published: July 2016

We propose to construct an optical interferometer to produce high resolution images by aperture synthesis. The interferometer, known as the Masked Aperture Pupil-Plane Interference Telescope (MAPPIT), will be mounted at the coudé focus of the Anglo-Australian Telescope. It will use a non-redundant aperture mask, together with closure phase methods developed for radio VLBI, to overcome the wavefront distortions which are introduced by atmospheric turbulence. By using the techniques of pupil-plane interferometry and wavelength dispersion, it is hoped that MAPPIT will have more sensitivity than many other interferometric imaging projects.
The Giant Radio Galaxy 0319-45 (MSH 03-43)
Authors: Jones P. A.
Published: July 2016

The extended radio source 0319-453 (MSH 03-43) was observed with the Molonglo Observatory Synthesis Telescope as part of a program to study a large sample of southern extragalactic radio sources. The low level structure showed a ridge pointing towards the nearby source 0317-456, which also showed low level structure. It is suggested that the two sources are the asymmetric lobes of a radio galaxy identified with the magnitude 15 peculiar dust-land galaxy AM 0319-452. The galaxy redshift of z = 0.0633 and the radio size of 25.6 arcmin give a projected size of 1.27 Mpc (H = 100 kms−1 Mpc−1). Thus it is one of the largest radio galaxies.
Short-Period Comet Production in Close Encounters with Jupiter
Authors: Olsson-Steel Duncan , Taaffe Lynne , Williams Simon
Published: July 2016

A method for calculating the resultant probability distributions of orbital elements for a small body (a comet, asteroid or meteoroid) after a gravitational encounter with a planet is described. This technique incorporates the frequency of such encounters so that the chance of attaining a certain new orbit per unit time is derived. The use of this technique is then illustrated by considering the effect of Jupiter upon the orbits of near-parabolic comets with perihelia near that planet (q= 5.2 AU) and in the inner solar system (q= 1.0 AU), with prograde (i= 10°) and retrograde (i= 170°) paths. As indicated by previous authors the prograde comets are more easily captured into short-period (P< 20 yr) and intermediate-period (20<P<200 yr) orbits; however, in contradiction to most previous work but in agreement with the results of Stagg and Bailey (submitted toMon. Not. R. Astron. Soc.) it is found that the comets with smaller perihelia, rather than those with perihelia near Jupiter, have higher capture probabilities. This is apparently due to the fact that a small deflection only is needed to sufficiently decelerate a comet onto a smaller orbit if it makes a near-perpendicular crossing of Jupiter’s path, whereas a larger deflection (to achieve a large orbital change) is needed if the paths are near-parallel. With comparatively modest amounts of computer time this method may be used to calculate the relative capture probabilities as a function ofiandqfor all values of interest, and is thus a useful precursor to integrations following orbital evolution, since it indicates the most likely avenues whereby shorter-period comets are derived from the near-parabolic flux.
Coronal Loops in Solar Active Regions
Authors: Durrant C. J. , Brown S. F.
Published: July 2016

We discuss the appearance of solar active regions as seen in EUV line radiation in terms of a system of simple static coronal loop models. The loop models are based on those of Rosner et al. (1978) and may be understood in terms of the scaling laws introduced by these authors. We present here some generalized scaling laws which demonstrate that the global properties of loops in fixed length are insensitive to everything but the overall heating rate or the basal pressure. The model and scaling laws appear to describe hot loops (T< 106K) well. Empirically determined temperatures and densities in cooler loops are not in agreement with coronal loop models.

We have computed a simple model of an active region using a dipole magnetic structure. The individual loop structures were calculated on the basis of the two different assumptions of constant basal pressure and of constant heating rate. This paper presents a preliminary discussion of the results and a comparison with observation.
Solar Radio Observations at 843 MHz
Authors: Gray A. D. , Campbell-Wilson D. , Large M. I.
Published: July 2016

The Molonglo Observatory Synthesis Telescope (MOST) has been used to observe the Sun with total-power fan-beams having a one-dimensional resolution of 41 arcsec at 843 MHz. The scans reveal clearly the rotation and evolution of the slowly-varying component as well as some burst activity. Low radio brightness features have also been identified, but the exact relationship between these features and coronal holes is, as yet, unclear. Several partial synthesis observations have been used to generate two-dimensional radioheliograms.
12.2 GHz Methanol Absorption towards Sgr A
Authors: Peng R. S. , Whiteoak J. B.
Published: July 2016

Line absorption associated with the 12.2 GHz 20 − 3-1 transition of CH3OH has been mapped towards Sgr A with the Parkes 64-m radio telescope and a 2 arcmin beam. Two concentrations are present, both offset from the continuum peak, with velocities of 18 and 46 km s-1 and line-to-continuum ratios of 0.59 and 0.30. For the higher ratio the column density is almost 1017 cm-2. The concentrations may be associated with a molecular cloud which overlies Sgr A East but lies in part behind Sgr A West.
Modelling The Universe
Authors: Monaghan J. J.
Published: July 2016

The question of modelling a wide variety of astrophysical phenomena is discussed. It is argued that the combination of new computing equipment and algorithms has created the opportunity for a concerted attack on problems ranging from star formation to the evolution of the universe.
Two Models for the Radio Spectra of Stellar Flares
Authors: Beardwood R. J. , Melrose D. B.
Published: July 2016

There are two current models for the typical radio spectra of flare stars, which have a broad peak around a frequency typically 1 – 10 GHz. One model involves both optically thick and optically thin emission, with the turnover attributed to the source becoming self-absorbed. The other model involves only emission at optical depth unity, so that observing different frequencies corresponds to ‘seeing’ different regions in the source. The two models are reviewed, and new calculations for an inhomogeneous source presented.