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A prompt radio burst has been observed from the supernova 1987a in the Large Magellanic Cloud. Observations were made at 0.843, 1.415, 2.29, and 8.41 GHz. At frequencies around 1 GHz, the peak flux density reached about 150 mJy and occurred within four days of the supernova. This event may be a weak precursor to a major radio outburst of the type previously observed in other extragalactic supernovae. Radio monitoring of the supernova is continuing at each of the above frequencies, and coordination is underway of a southern hemisphere VLBI array to map the radio outburst region as it expands. Differential astrometry carried out on prime-focus plates taken with the Anglo-Australian telescope indicates that the component, star 1, of Sanduleak's star SK-69202 is within 0.05 ± 0.13 arcsec of the supernova.
The Antarctic Roadmap Challenges (ARC) project identified critical requirements to deliver high priority Antarctic research in the 21st century. The ARC project addressed the challenges of enabling technologies, facilitating access, providing logistics and infrastructure, and capitalizing on international co-operation. Technological requirements include: i) innovative automated in situ observing systems, sensors and interoperable platforms (including power demands), ii) realistic and holistic numerical models, iii) enhanced remote sensing and sensors, iv) expanded sample collection and retrieval technologies, and v) greater cyber-infrastructure to process ‘big data’ collection, transmission and analyses while promoting data accessibility. These technologies must be widely available, performance and reliability must be improved and technologies used elsewhere must be applied to the Antarctic. Considerable Antarctic research is field-based, making access to vital geographical targets essential. Future research will require continent- and ocean-wide environmentally responsible access to coastal and interior Antarctica and the Southern Ocean. Year-round access is indispensable. The cost of future Antarctic science is great but there are opportunities for all to participate commensurate with national resources, expertise and interests. The scope of future Antarctic research will necessitate enhanced and inventive interdisciplinary and international collaborations. The full promise of Antarctic science will only be realized if nations act together.
We describe the performance of the Boolardy Engineering Test Array, the prototype for the Australian Square Kilometre Array Pathfinder telescope. Boolardy Engineering Test Array is the first aperture synthesis radio telescope to use phased array feed technology, giving it the ability to electronically form up to nine dual-polarisation beams. We report the methods developed for forming and measuring the beams, and the adaptations that have been made to the traditional calibration and imaging procedures in order to allow BETA to function as a multi-beam aperture synthesis telescope. We describe the commissioning of the instrument and present details of Boolardy Engineering Test Array’s performance: sensitivity, beam characteristics, polarimetric properties, and image quality. We summarise the astronomical science that it has produced and draw lessons from operating Boolardy Engineering Test Array that will be relevant to the commissioning and operation of the final Australian Square Kilometre Array Path telescope.
Not only is depression associated with increased inflammation but inflammation is a risk factor for the genesis of depression. Many of the environmental risk factors for depression are transduced through inflammatory signaling. Anti-inflammatory agents show promise for the management of depression in preclinical, epidemiological, and early clinical studies. This opens the door to the potential for anti-inflammatory agents to treat and prevent depression. There are no evidence-based pharmacotherapies for depression prevention.
ASPREE-D, aspirin in the prevention of depression in the elderly, is a sub study of ASPREE, which explores the potential of aspirin to prevent a range of inflammation related disorders in the elderly. With a sample size of 19,114, and a duration of 5 years, this placebo controlled study will be one of the largest randomized controlled trials in psychiatry and will provide definitive evidence on the ability of aspirin to prevent depression.
This paper presents the rationale for the study and presents a summary of the study design.
ASPREE-D may not only define novel therapy but will provide mechanistic proof of concept of the role of inflammation in depression.
NGC 7027 is justifiably THE template spectrum for PNe. Its vast range of emission species – from molecular and neutral to ions with ionization potential > 120eV – its high surface brightness and accessibiliy for northern observatories make it the PN laboratory of choice. However the quality of the spectra from the UV to the IR is mixed, many line fluxes and identifications still remaining unchecked from photographic or image tube spectra. Very deep spectra of NGC 7027 (emission line strengths <10-4 of Hβ) in the 0.65 to 1.05μm region (Baluteau et al. 1995) showed the presence of many faint emission lines. Pequignot & Baluteau (1994) showed that heavy elements from the 4th, 5th and 6th rows of the Periodic Table have much higher abundances than Solar, confirming the synthesis of neutron capture elements in low mass stars and providing new constraints on stellar evolution theory.
We have obtained optical recombination-line abundances for the third-row element magnesium in ten planetary nebulae. The nebulae in our sample include four (NGC 7009, NGC 6153, M 2–36 and M 1–42) for which we have previously found very large enhancements, relative to solar, in the recombination line abundances of the second-row elements carbon, nitrogen, oxygen and neon (Liu et al. 1995, Liu et al. 2000, Liu et al. 2001). Nebular temperature fluctuations appear unable to account for these effects. However, models that invoke high-density clumps, particularly clumps which are hydrogen-deficient, appear more viable as an explanation for the high recombination line abundances that are observed (see Liu et al. 2000 for more details). While it may be possible to appeal to astrophysical nucleosynthetic processes to enhance the CNONe second-row elements in AGB stars, such effects are not expected to modify the abundances of third-row elements such as magnesium. We have therefore measured and dereddened the intensities of the 4481 Å 4f-3d line of Mg II, relative to Hβ, in order to investigate whether magnesium recombination line abundances are enhanced or not.
A new class of planetary nebulae, in which abundances derived from optical recombination lines (ORL) seem to be much larger than those derived from collisionally excited lines (CEL) by up to one or two orders of magnitude is now well identified (Liu, these proceedings and references therein).
Photoionization models including two components, one highly enriched in C, N, O, Ne and deficient in H and the other one of more usual composition, can account for most of the numerous spectroscopic data available from UV to far-IR in two of the best observed, most extreme examples, namely NGC 6153 and M142 (Péquignot et aI., 2002, and in preparation). The few discrepancies left can generally be understood in terms of inaccuracy of the observations (calibration of infrared line fluxes relative to the optical) and some atomic data, particularly in the unusual conditions prevailing in the H-deficient component.
The University of NSW’s Automated Patrol Telescope is a modified Baker-Nunn satellite tracking camera, now used for CCD imaging of astronomical objects. The f/1 Baker-Nunn optical design gives a 30° field of view with an approximately spherical focal surface of radius ≈500 mm. While the focal plane curvature is tolerable across the 1.4° × 1.0° field of the present CCD, it becomes unacceptable when a larger CCD is used. In addition, the use of glass filters in the highly convergent beam produces intolerable spherical aberration. We present a design modification to the original Baker-Nunn which enables a 5° diameter flat field to be produced when using B, V, R or I filters. By making this modification, we plan to perform multicolour imaging, using a new large-format CCD with a 2.9° × 1.9° field of view.
Our knowledge of the universe comes from recording the photon and particle fluxes incident on the Earth from space. We thus require sensitive measurement across the entire energy spectrum, using large telescopes with efficient instrumentation located on superb sites. Technological advances and engineering constraints are nearing the point where we are recording as many photons arriving at a site as is possible. Major advances in the future will come from improving the quality of the site. The ultimate site is, of course, beyond the Earth’s atmosphere, such as on the Moon, but economic limitations prevent our exploiting this avenue to the degree that the scientific community desires. Here we describe an alternative, which offers many of the advantages of space for a fraction of the cost: the Antarctic Plateau.
The Automated Patrol Telescope (APT) is a wide-field CCD imaging telescope operated by the University of New South Wales at Siding Spring Observatory in Australia. The optical design employed resembles that of a Schmidt, but uses a 3-element lens to achieve a wide, corrected field of view. The APT was developed by extensively modifying the optical, mechanical and electronic systems of a Baker-Nunn satellite tracking camera. Telescope motion and operation of the CCD have been placed under computer control, allowing automated observations for longterm survey and monitoring projects. The APT has 0.5 m aperture f/1 optics which produce a 5° flat field, of which a 2°×3° field is covered by the CCD currently installed. The telescope is being used for studies of stellar activity in open clusters and regions of star formation, and comet and minor planet investigations. A number of other projects for the APT are being considered, including searches for novae, supernovae in clusters of galaxies, and brown dwarfs.
This paper describes the system architecture of a newly constructed radio telescope – the Boolardy engineering test array, which is a prototype of the Australian square kilometre array pathfinder telescope. Phased array feed technology is used to form multiple simultaneous beams per antenna, providing astronomers with unprecedented survey speed. The test array described here is a six-antenna interferometer, fitted with prototype signal processing hardware capable of forming at least nine dual-polarisation beams simultaneously, allowing several square degrees to be imaged in a single pointed observation. The main purpose of the test array is to develop beamforming and wide-field calibration methods for use with the full telescope, but it will also be capable of limited early science demonstrations.
Antarctic and Southern Ocean science is vital to understanding natural variability, the processes that govern global change and the role of humans in the Earth and climate system. The potential for new knowledge to be gained from future Antarctic science is substantial. Therefore, the international Antarctic community came together to ‘scan the horizon’ to identify the highest priority scientific questions that researchers should aspire to answer in the next two decades and beyond. Wide consultation was a fundamental principle for the development of a collective, international view of the most important future directions in Antarctic science. From the many possibilities, the horizon scan identified 80 key scientific questions through structured debate, discussion, revision and voting. Questions were clustered into seven topics: i) Antarctic atmosphere and global connections, ii) Southern Ocean and sea ice in a warming world, iii) ice sheet and sea level, iv) the dynamic Earth, v) life on the precipice, vi) near-Earth space and beyond, and vii) human presence in Antarctica. Answering the questions identified by the horizon scan will require innovative experimental designs, novel applications of technology, invention of next-generation field and laboratory approaches, and expanded observing systems and networks. Unbiased, non-contaminating procedures will be required to retrieve the requisite air, biota, sediment, rock, ice and water samples. Sustained year-round access to Antarctica and the Southern Ocean will be essential to increase winter-time measurements. Improved models are needed that represent Antarctica and the Southern Ocean in the Earth System, and provide predictions at spatial and temporal resolutions useful for decision making. A co-ordinated portfolio of cross-disciplinary science, based on new models of international collaboration, will be essential as no scientist, programme or nation can realize these aspirations alone.
Gattini and CSTAR have been installed at Dome A, Antarctica, which provide time-series photometric data for a large number of pulsating variable stars. We present the study for several variable stars with the data collected with the two facilities in 2009 to demonstrate the scientific potential of observations from Dome A for asteroseismology.
PILOT (the Pathfinder for an International Large Optical Telescope) is a proposed 2.5-m optical/infrared telescope to be located at Dome C on the Antarctic plateau. Conditions at Dome C are known to be exceptional for astronomy. The seeing (above ∼30 m height), coherence time, and isoplanatic angle are all twice as good as at typical mid-latitude sites, while the water-vapour column, and the atmosphere and telescope thermal emission are all an order of magnitude better. These conditions enable a unique scientific capability for PILOT, which is addressed in this series of papers. The current paper presents an overview of the optical and instrumentation suite for PILOT and its expected performance, a summary of the key science goals and observational approach for the facility, a discussion of the synergies between the science goals for PILOT and other telescopes, and a discussion of the future of Antarctic astronomy. Paper II and Paper III present details of the science projects divided, respectively, between the distant Universe (i.e. studies of first light, and the assembly and evolution of structure) and the nearby Universe (i.e. studies of Local Group galaxies, the Milky Way, and the Solar System).
PILOT (the Pathfinder for an International Large Optical Telescope) is a proposed 2.5-m optical/infrared telescope to be located at Dome C on the Antarctic plateau. The atmospheric conditions at Dome C deliver a high sensitivity, high photometric precision, wide-field, high spatial resolution, and high-cadence imaging capability to the PILOT telescope. These capabilities enable a unique scientific potential for PILOT, which is addressed in this series of papers. The current paper presents a series of projects dealing with the nearby Universe that have been identified as key science drivers for the PILOT facility. Several projects are proposed that examine stellar populations in nearby galaxies and stellar clusters in order to gain insight into the formation and evolution processes of galaxies and stars. A series of projects will investigate the molecular phase of the Galaxy and explore the ecology of star formation, and investigate the formation processes of stellar and planetary systems. Three projects in the field of exoplanet science are proposed: a search for free-floating low-mass planets and dwarfs, a program of follow-up observations of gravitational microlensing events, and a study of infrared light-curves for previously discovered exoplanets. Three projects are also proposed in the field of planetary and space science: optical and near-infrared studies aimed at characterising planetary atmospheres, a study of coronal mass ejections from the Sun, and a monitoring program searching for small-scale Low Earth Orbit satellite debris items.
The cold, dry, and stable air above the summits of the Antarctic plateau provides the best ground-based observing conditions from optical to sub-millimetre wavelengths to be found on the Earth. Pathfinder for an International Large Optical Telescope (PILOT) is a proposed 2 m telescope, to be built at Dome C in Antarctica, able to exploit these conditions for conducting astronomy at optical and infrared wavelengths. While PILOT is intended as a pathfinder towards the construction of future grand-design facilities, it will also be able to undertake a range of fundamental science investigations in its own right. This paper provides the performance specifications for PILOT, including its instrumentation. It then describes the kinds of projects that it could best conduct. These range from planetary science to the search for other solar systems, from star formation within the Galaxy to the star formation history of the Universe, and from gravitational lensing caused by exo-planets to that produced by the cosmic web of dark matter. PILOT would be particularly powerful for wide-field imaging at infrared wavelengths, achieving near diffraction-limited performance with simple tip–tilt wavefront correction. PILOT would also be capable of near diffraction-limited performance in the optical wavebands, as well be able to open new wavebands for regular ground-based observation, in the mid-IR from 17 to 40 μm and in the sub-millimetre at 200 μm.
PILOT (the Pathfinder for an International Large Optical Telescope) is a proposed 2.5-m optical/infrared telescope to be located at Dome C on the Antarctic plateau. The atmospheric conditions at Dome C deliver a high sensitivity, high photometric precision, wide-field, high spatial resolution, and high-cadence imaging capability to the PILOT telescope. These capabilities enable a unique scientific potential for PILOT, which is addressed in this series of papers. The current paper presents a series of projects dealing with the distant (redshift >1) Universe, that have been identified as key science drivers for the PILOT facility. The potential for PILOT to detect the first populations of stars to form in the early Universe, via infrared projects searching for pair-instability supernovae and gamma-ray burst afterglows, is investigated. Two projects are proposed to examine the assembly and evolution of structure in the Universe: an infrared survey searching for the first evolved galaxies at high redshift, and an optical survey aimed at characterising moderate-redshift galaxy clusters. Finally, a large-area weak-lensing survey and a program to obtain supernova infrared light-curves are proposed to examine the nature and evolution of dark energy and dark matter.
We have reviewed the X-ray pulse profiles from a large number of observations of the accreting binary pulsar GX 1+4 obtained during the last 25 years. The profiles cover various energy ranges between 1 and 100 keV. Using these data we present a coherent picture of present and past pulse profiles and the variations of these pulse profiles with time. The pulse shape is dependent on both the X-ray luminosity and whether the pulsar is spinning up or down. Profiles measured during the GX 1+4 high state in the 1970s are all trailing edge bright. Subsequently the profiles have generally been symmetric or leading edge bright. Rossi X-ray Timing Explorer (RXTE) satellite data taken in July 1996 show that similar pulse shape variations can occur on a timescale of hours. The implications of this new information for accretion models is discussed.
The near infrared sky spectral brightness has been measured at the South Pole with the Near Infrared Sky Monitor (NISM) throughout the 2001 winter season. The sky is found to be typically more than an order of magnitude darker than at temperate latitude sites, consistent with previous South Pole observations. Reliable robotic operation of the NISM, a low power, autonomous instrument, has been demonstrated throughout the Antarctic winter. Data analysis yields a median winter value of the 2.4μm (Kdark) sky spectral brightness of ˜120μJy arcsec−2 and an average of 210 ± 80μJy arcsec−2. The 75%, 50%, and 25% quartile values are 270 ± 100, 155 ± 60, and 80 ± 30μJy arcsec−2, respectively.