bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Proposal for an Australian Space Astronomy Data Centre
Authors: Tuohy Ian R. 
Published: July 2016

AbstractThe concept of a national centre for the analysis of archival and contemporary space astronomy data has been identified as a highly desirable objective by the Australian astronomical community for a number of years. With the approaching launch of the Hubble Space Telescope (HST), the time is now appropriate to actively pursue this objective. HST will generate a data archive of unique astrophysical significance over the course of the ≥ 20 year mission. It is essential that Australian astronomers have efficient access to this resource, both to maintain our position at the forefront of astronomical research, and to complement our major ground-based facilities (particularly the AAT and the Australia Telescope). An Australian facility would provide efficient access to HST data and also to the analysis tools and expertise necessary for utilizing the data. Archival data from other NASA and ESA missions could also be supported, and in the longer term, the facility could become the science centre for the Lyman/Quasat missions.This paper presents the case for an Australian Space Astronomy Data Centre, reviews the astronomy missions of relevance, and addresses the role, scope and implementation timescale of the facility. Preliminary estimates are given for the resources that will be required, and possible routes for funding the centre are outlined. Above all, the report is intended as a Discussion Paper to promote further consideration of the concept and of the service that could be provided to the Australian astronomical community.
Evolution of a Horizontal Scale for Magnetoconvection
Authors: Murphy J. O. , Lopez J. M. 
Published: July 2016

AbstractThe non-linear modal equations governing magnetoconvection in a fluid layer have been integrated forward in time incorporating a discrete spectrum of horizontal wave numbers, distributed within the range supporting convection. By progressively deleting some of the decaying modes and introducting additional modes within the range of growth it is possible to establish the evolution, or otherwise, of a preferred horizontal scale, which determines the horizontal cell size of the convective motions. Further, the influence of the magnetic field strength on cell extent can also be determined.
Star Formation in Cooling Flows (Invited Paper)
Authors: Nulsen P. E. J. , Johnstone R. M. , Fabian A. C. 
Published: July 2016

AbstractX-ray data show that substantial quantities of hot gas are cooling near the centres of many clusters and groups of galaxies. The existence of such cooling flows has been challenged because of the lack of evidence for star formation from the cooled gas. Spectra of cooling flow galaxies show filling in of the continuum shortward of the break at 4000 Å relative to normal elliptical galaxies. This is consistent with some continuing star formation. Extended regions of line emission are commonly associated with cooling flows. If the initial-mass-function of the newly formed stars which affect the 4000 Å break is like that which applies in the solar neighbourhood, then these stars can also power the line emission. The strength of the 4000 Å break is shown to correlate with the Hβ flux in the manner expected when this is the case. This allows us to esimate the star formation rate from the line luminosity.The rate of star formation required to account for the line emission still falls well short of the rate at which gas is inferred to be cooling. It is argued that, nevertheless, the cooling gas is probably forming into stars. The overall initial-mass-function must be different from that which applies in the solar neighbourhood, but this should not be surprising given the different ambient conditions in a cooling flow.
Gamma-Ray Astronomy From Balloons and Satellites (Invited Paper)
Authors: Sood R. K. 
Published: July 2016

AbstractGamma-ray astronomy has traditionally been a difficult field of research due to the low fluxes from astronomical objects and the inherently poor angular response of detectors. Progress made in the field in the last twenty years is reviewed. Many major astrophysical problems can only be addressed with the future operation of more sensitive satellite experiments. Recent gamma-ray observations of the supernova SN1987 a are briefly discussed.
A Multi-Purpose, Multi-Channel Radiospectrograph for the Parkes Telescope
Authors: Lim J. , Nelson G. J. , Vaughan A. E. 
Published: July 2016

AbstractThe design and scientific applications of a 96-channel filter spectrograph of 1 MHz resolution are presented. The spectrograph is currently under construction and will be installed on the Parkes telescope in 1987-1988. Its main scientific objective is dynamic spectral studies of decimetre- and metre-wavelength bursts from flare stars. However, it will also be used for performing large-scale pulsar surveys, and dynamic spectral observations of interplanetary scintillation of compact sources, interstellar scintillation of compact extragalactic sources, and interesting radio sources in general.We show that plasma emission generated in the coronae of flare stars should be detectable at metre- and decimetre-wavelengths. We plan to search for fundamental and second-harmonic plasma radiation by observing in two harmonically related bands, 200 to 250 MHz and 400 to 500 MHz. With noise-adding to stabilize receiver gain, the sensitivity (3σ) of each channel of the spectrograph is ∼ 1.5 Jy for a 1-s integration. Previous studies have reported peak flux densities of up to ∼ 35 Jy and ∼ 12 Jy at 240 MHz and 410 MHz respectively for radio bursts from flare stars.
How unique was SN 1987A?
Authors: van den Bergh S. 
Published: July 2016

AbstractSupernovae of type II (SN II) are found to exhibit a correlation (r = 0.45 ± 0.15) between M(max) and parent galaxy luminosity. This correlation might be understood by assuming that the metal-rich red supergiant progenitors of SN II in luminous galaxies have more extended photospheres than do those of the more metal-deficient evolved progenitors of SN II on low-luminosity galaxies. For h = 0.5 it is found that SN 1987A was ∼1.5 mag fainter at maximum in blue light than any other well-observed SN II. For h = 1.0 SN 1948B, SN 1973R, SN 1972Q and SN 1987A exhibit comparable MB(max). It would be important to undertake systematic searches for sub-luminous SN II in dwarf galaxies and in the metal-poor extreme outer regions of giant- and supergiant spirals.
Infrared Observations of SN 1987A: Probing the Ejecta and its Surrounding Medium
Authors: Dwek E. 
Published: July 2016

AbstractThe extremely rare occurrence of a relatively nearby supernova, SN 1987A, provides astronomers with a unique opportunity to conduct the most detailed multi-wavelength analysis of this event and its effect on the ambient medium. Looking inside the supernova, astronomers are getting their first ‘unbiased’ view of the composition of the expanding ejecta. The infrared (IR) region of the spectrum can carry the signature of products ranging from heavy elements, synthesised during the early phases of the expansion, to molecules and dust formed after the ejecta underwent significant cooling. Probing the ambient medium, IR observers can gain information on the presence and distribution of dust in close proximity (∼1 pc) to the supernova (SN), and on the interaction of the SN blast wave with the surrounding dusty medium. At larger distances from the SN, they can set constraints on dust properties in the scattering dust layers detected at distances of ∼120 and ∼330 pc from the supernova.
Observations of SN 1987A from Ginga
Authors: Inoue H. 
Published: July 2016

AbstractResults of the observations of SN 1987A from Ginga are presented. The first detection of X-rays from the SN 1987A was July, 1987. The energy spectrum is quite unnusual for any of the known classes of X-ray sources, and apparently consists of two seperate components; a soft and a hard component. The soft component is significantly time-variable, and also showed a flarelike increase in January, 1988. Whereas, the intensity of the hard component has remained fairly stationary for more than 300 days. The origins of the two components are also discussed.
Taxonomy of Supernovae
Authors: Filippenko Alexei V. 
Published: July 2016

AbstractI review the observed properties of supernovae (SNe), concentrating on recent results obtained from high-quality optical spectra. Although most SNe Ia have similar characteristics at comparable phases, there are some notable variations, particularly in the velocities of the ejecta. Moreover, there is very preliminary evidence for significant differences between the spectra of SNe Ia in H II regions and in elliptical galaxies. SNe II exhibit a wide range of spectral properties, as expected if they are produced by massive stars. At late times strong lines of [O I] and [Ca II] appear in most SNe II, including SN 1987A. In some objects, however, these are absent; the spectrum of SN 1987F, for instance, closely resembled that of a Seyfert 1 nucleus, with prominent H I and Fe II emission lines. Type Ib SNe, which lack the 6150Â absorption band typical of SNe la near maximum brightness, develop strong emission lines of [O I] and [Ca II] many months past maximum, but hydrogen is absent. Hα emission with a P-Cygni profile has, on the other hand, been detected in the early-time spectrum of SN 1987K, an object which later became spectroscopically indistinguishable from an old SN Ib. There is evidence for very weak Hα in the early spectra of several additional SNe Ib. Moreover, 7 – 8 months past maximum the [O I]/Hα and [Ca II]/Hα intensity ratios in SN 1987A were higher than in a few other well-observed SNe II at corresponding times. Hence, Type II and Type Ib SNe may form a continuous sequence in which the mass of the hydrogen envelope is the main variable.
A Model for Solar Flares Invoking Weak Double Layers
Authors: Khan J. I. 
Published: July 2016

AbstractA simple model for solar flares is described which invokes many ion-acoustic double layers in the source region. The ability of the model to explain some of the observed characteristics of solar flares is discussed, particular attention being paid to the well-observed high-energy flare examined by de Jager et al. (1987).
The Buoyancy of U-Loops
Authors: Wilson P. R. 
Published: July 2016

AbstractThe problem of the surface migration of solar magnetic fields is discussed. It is shown that, unless some form of reconnection takes place below the surface, magnetic tension should effectively prevent such migration and the possibility of U-loop formation and transport is considered. As a first step, the buoyancy of a magnetic ‘U-loop’ within an isothermal atmosphere is considered. It is shown that such a configuration may form by the reconnection of the arms of an Ω-loop associated with an active region, and is likely to be buoyant initially and rise through the region. However, as it rises, the net buoyancy decreases and, provided that the temperature within the loop is even marginally less than that outside, it will reach a sub-surface configuration in which the net buoyancy is zero. The significance of this result for solar magnetic fields is then assessed.
The Stability of Swirling Jets
Authors: Coleman Colin S. 
Published: July 2016

AbstractThe stability of a swirling cylindrical jet of compressible fluid is examined by performing a normal mode analysis and numerically solving the eigenvalue problem. Perturbations of the form f(r)exp[i(ωt-mϕ-kz)] are considered, where f is any fluid variable. Instabilities which are characteristic of both a non-swirling (top-hat) jet and a Rankine vortex are investigated for a particular axial wavenumber.The vortex instabilities are weak, and are found to remain weak when axial flow is present. The jet instabilities are much stronger, but axial flow is a stabilizing influence. The positive helicity (km > 0) non-axisymmetric modes (m ≠ 0) are stabilized by a small component of azimuthal flow. The axisymmetric mode (m = 0) and the negative helicity non-axisymmetric modes persist in rapidly swirling jets, but with a greatly reduced growth rate.
The Design and Construction of the University of Adelaide Bicentennial Gamma-Ray Telescope
Authors: Clay R. W. , Giles D. H. , Gregory A. G. , Patterson J. R. , Prescott J. R. , Protheroe R. J. , Smith N. I. , Taaffe L , Wild N. 
Published: July 2016

AbstractThe design and construction of the 30 m2 Bicentennial Gamma Ray Telescope at Woomera South Australia is described. This novel instrument is now completed and commissioning is underway. It is designed to observe astronomical sources at energies greater than ∼ 500 GeV by means of atmospheric Cerenkov light. It contains 55 spherical, glass mirrors of focal length 2.66 m arranged in three groups of 10 m2, to focus the light onto three sets of detectors operated in fast co-incidence. The recording electronics includes a rubidium clock to enable pulsars to be studied.
Development of the Buckland Park Air Shower Array for Anisotropy Measurements
Authors: Bird D. J. , Clay R. W. 
Published: July 2016

AbstractThe cosmic ray array at Buckland Park is being developed to extend its useful collecting area at 1016 eV to ∼105m2 so that anisotropy measurements can be made at higher energies than previously possible with that system. A new array is also being designed to assist with this investigation. Design considerations for the new arrays are discussed.
Photometric Observations of Flares on Proxima Centauri
Authors: Kroupa P. , Burman R. R. , Blair D. G. 
Published: July 2016

AbstractProxima Centauri was observed photoelectrically in the period July-September 1987 with a newly-installed computer-interfaced photometer. Four definite flares and six further possible events were recorded. The level of Proxima’s flaring activity was examined and no significant change since 1969 found.
The Fleurs Southern Benchmark Program
Authors: Batty Michael J. , White Graeme L. , Bunton John D. , Brown David R. , Corben Julian B. 
Published: July 2016

AbstractA program to determine accurate radio positions and optical identifications of southern flat-spectrum radio sources has been undertaken with the six-dish array of the Fleurs synthesis telescope at 1.4 GHz and using the SERC J sky survey. This sample covers the declination range −80° to −50° and comprises all 198 sources from the Parkes catalogue with α of > −0.5 and flux density of 0.25 Jy.The radio astrometric phase of the program is complete. We conclude that by comparison with accurate VLBI positions the FST positions have r.m.s. uncertainties of ∼0″.9. There is no global bias in the FST positions at the 0″.2 to 0″.3 level relative to the JPL VLBI extragalactic reference frame. A comparison with positions from the Parkes catalogue shows that in the southern regions the Parkes catalogue has rms position errors of about 9″. There is no significant bias between the FST and Parkes positions.
Radio Polarization and Magnetic Fields in Six Supernova Remnants
Authors: Milne D. K. , Caswell J. L. , Kesteven M. J. , Haynes R. F. , Roger R. S. 
Published: July 2016

Abstract8.4 GHz linear polarization maps, obtained with the Parkes radio telescope, are presented for six southern supernova remnants. These results are compared with published and unpublished polarization maps at 5 GHz to derive the magnetic field direction and Faraday rotation measure distribution.These results are part of a program to map the magnetic fields in galactic supernova remnants and complement our program to obtain high-resolution maps of galactic SNRs using the Molonglo Observatory Synthesis Telescope; five new Molonglo maps are presented here.
The Space Distribution of Local Radio and X-ray Galaxies
Authors: Shaver P. A. 
Published: July 2016

Extended abstractLocal large scale structure is best studied using statistically complete samples which cover the entire sky, and for which full redshift information is available. The optical galaxy redshift surveys which have been made to date involve many thousands of objects but cover only limited parts of the sky, and so provide only a fragmented picture of local large scale structure. Complete samples of radio and X-ray galaxies are available, however, with large sky coverage. While the number of objects is small, they may still suffice to define the dominant local structures, particularly as they may preferentially sample the deeper gravitational potentials and so provide a more efficient tracer of dominant structure.
Australian Tree Ring Chronologies as Proxy Data for Solar Variability
Authors: Murphy J. O. 
Published: July 2016

AbstractData from the Solar Maximum Mission satellite suggests that there is a 0.1 percent variation in solar luminosity over the 11-year solar cycle with maximum output corresponding to maximum sunspot number. Tree ring chronologies can be utilized as proxy data to compile a record of the magnitude of past solar variability. Spectral analysis of tree ring series compiled from a site in Tasmania has established, among others, significant periodicities of about 90 and 11 years. The application of band pass filter techniques shows that the 11-year cycle present in some tree ring series correlates with the Zurich sunspot numbers over the period from AD1700, the extent of accurate sunspot records, with a time lag of about three years.
(UK) Schmidt–AAO Style into the 1990s
Authors: Savage A. 
Published: July 2016

Abstract
This is a brief description of the way I see the Schmidt functioning through the next three years. There are four important functions which must be maintained: (a) The Science from the Schmidt material must continue to be of the same high quality as that on which the Schmidt’s reputation has been built; (b) The service we provide to the Australian and British communities must continue despite the new trim (slim) appearance of the Schmidt staff and budget; (c) We must maintain our links with ROE, its Plate Library, which is the archive for Schmidt plate material, and Photolabs which provide some of the survey atlases; (d) We are being actively encouraged to promote Australian and British usage of the UK’s large measuring machines APM and COSMOS. Additionally, we are continually being encouraged to improve our efficiency. There is still at least one area in which we can do this and this is discussed.
Preliminary Results from the Automated Patrol Telescope CCD Camera
Authors: Brooks P. W. 
Published: July 2016

Abstract
The University of NSW Automated Patrol Telescope (APT), a modified 0.5 m Baker-Nunn Schmidt telescope situated at Siding Spring Observatory, Coonabarabran, Australia, was opened in June 1989. It features the unique combination of an extremely fast (f/1) optical system with a CCD (Charge-Coupled Device) camera at the prime focus, capable of both fast (50 Hz TV-rate) imaging and slow-scan integrated readout via a low noise Correlated Double Sampling amplifier. This combination of optics and detector gives a wide field (0.9° × 1.4°) suited to observing extended objects including the LMC, SMC and galaxies in the Sculptor group. First images from the APT are presented along with the results of noise, linearity and dark current measurements made to date with a 12-bit analog-to-digital converter. Results were (ADU = Analog-Digital Unit):
APM Surveys for High Redshift QSOs
Authors: Irwin M. J. , McMahon R. G. 
Published: July 2016

AbstractThe first QSO with a redshift z > 4 was found using a combination of UK Schmidt Telescope (UKST) plates and the APM automatic plate measuring machine (Warren et al. 1987a). By continuing to make use of UKST survey plates plus the APM facility we have added substantially to the number of known QSOs with z > 4. A brief description of the general survey technique is presented together with a preliminary discussion of some of the results obtained so far.
Observations of Six Southern Galaxies in the12CO(J = 1—0) Transition
Authors: Harnett J. I. , Wielebinski R. , Bajaja E. , Reuter H-P. , Hummel E. 
Published: July 2016

AbstractWe have mapped the southern galaxies NGC 613, 1313, 1433, 1566, 1672 and 2442 in the12CO(J = 1 → 0) transition with the 15-m Swedish European Submillimetre Telescope (SEST). The sample is based on galaxies previously observed in radio continuum with the Molonglo Observatory Synthesis Telescope (MOST). Strong emission is seen from the barred galaxies NGC 613 and NGC 2442 and from the active galaxies NGC 1566 and 1672. The weakest emission was from NGC 1433, while the Sd spiral NGC 1313 was not detected.
Two-channel Photometry of Cataclysmic Variables
Authors: Sullivan Denis J. 
Published: July 2016

AbstractHigh-speed photometry of two cataclysmic variables is presented. The observations were made using a two-channel photometric system and the Mt John 0.6 or 1-m telescopes at Lake Tekapo in New Zealand. Both objects have only recently been identified as cataclysmic variables. One of the objects is a high inclination system featuring a deep eclipse in the light curve and a 5.5 hour period, while the other object, despite being relatively faint, clearly exhibits a 2.5 hour period and out of eclipse variability. Simultaneous monitoring of a nearby comparison star for this latter object was particularly beneficial, even during good photometric conditions.
The Atmospheric Extinction at Yonsei University Observatory in 1982–89
Authors: Jeong Jang Hae 
Published: July 2016

AbstractMore than 1000 coefficients of atmospheric extinction in the U, B and V passbands were obtained as a secondary result of long-term photometric monitoring of stellar objects at Yonsei University Observatory during 1982–1989. The long-term variation of the extinction coefficients of each passband are presented in this paper.
Chemical Fractionation in Gas Rings and the Formation of the Solar System
Authors: Prentice A. J. R. 
Published: July 2016

AbstractThe anomalously high density of the planet Mercury and the higher-than-solar rock-to-ice ratio in Jupiter’s moons Ganymede and Callisto cannot be explained by the conventional disc models of solar system formation. It is shown here that the unusual chemical signature of these bodies is the outcome of a process of chemical fractionation and orbital focussing which is peculiar to gas ring models of planet and regular satellite formation. Good numerical agreement with the observational data is obtained if the temperature of condensation of the planetary system closely followed the law Tn ≃ 680[R⊕/Rn]0.9 K, where Rn denotes the radial distance from the Sun.
A Cloud Detector for Automated Telescopes
Authors: Ashley M. C. B. , Jurcevic J. S. 
Published: July 2016

AbstractAn instrument is described that can detect clouds at night-time by sensing their infrared emission. The device can readily detect clouds that are difficult to see with the unaided eye on a moon-lit night. It can be used to provide an indication of how photometric the conditions are, to terminate exposures when cloud forms, and to close the dome when conditions become unsuitable for observing. The detector also has applications as an astronomical site-surveying instrument.