Evolutionary Map of the Universe

EMU is a wide-field radio continuum survey planned for the new Australian Square Kilometre Array Pathfinder (ASKAP) telescope, due to be completed in 2012. The primary goal of EMU is to make a deep ($\sim 10\mu$Jy/bm rms) radio continuum survey of the entire Southern Sky at 1.4 GHz, extending as far North as +30$\deg$ declination, with a 10 arcsec resolution. EMU is expected to detect and catalog about 70 million galaxies, including typical star-forming galaxies up to z=1, powerful starbursts to even greater redshifts, and AGNs to the edge of the Universe. EMU will undoubtedly discover new classes of object. Here I present the science goals and survey parameters.Comment: The Spectral Energy Distribution of Galaxies Proceedings IAU Symposium No. 284, 2011, R.J. Tuffs & C.C.Popescu, ed

Endocannabinoid Involvement in Impulsivity and Decision-making

Problem gambling is a widespread phenomenon with a prevalence estimate of 2.3% globally (Williams, Volberg, & Stevens, 2012). Although little is known about the neurochemistry underlying this pathological behaviour, evidence suggests that dysregulation of the brain’s endocannabinoid (eCB) system may be implicated in impulsivity and decision-making. For example, chronic cannabis users exhibit impulsive behaviour and impaired decision-making on the Iowa Gambling Task (IGT). The present study sought to further examine the role of the eCB system in problem gambling-related decision-making in laboratory rats using the five-choice serial reaction time task (5-CSRTT), and a recently-developed rodent analogue of the IGT called the rat gambling task (rGT). It was predicted that increasing neural levels of the eCB anandamide by administering the fatty acid amide hydrolase (FAAH) inhibitor URB597 would increase impulsivity as found previously with psychomotor stimulants. Results revealed that URB597 (0.03-1 mg/kg, IP) had no effect on premature responding or correct choices. Cocaine (15 mg/kg, IP) increased premature responding and decreased choice accuracy in the 5-CSRTT, but these effects were not attenuated by the CB1 inverse agonist rimonabant (3 mg/kg, IP). Furthermore, neither URB597 (0.03-1 mg/kg, IP) nor the cannabinoid receptor agonist THC (1.0-1.5 mg/kg, IP) altered optimal choice preference or premature responding in the rGT. Taken together, results did not support the notion that eCBs are involved in impulsivity or decision-making. We also conclude that any involvement of the eCB system in impulsivity is likely a downstream process from dopamine release

ASKAP-EMU: Overcoming the challenges of wide deep continuum surveys

Next-generation continuum surveys will be strongly constrained by dynamic range and confusion. For example, the ASKAP-EMU (Evolutionary Map of the Universe) project will map 75% of the sky at 20cm to a sensitivity of 10 μJy – some 45 times deeper than NVSS, and is likely to be challenged by issues of confusion, cross-identification, and dynamic range. Here we describe the survey, the issues, and the steps that can be taken to overcome them. We also explore ways of using multiwavelength data to penetrate well beyond the classical confusion limit, using multiwavelength data, and an innovative outreach approach to cross-identification

Gamma-Ray Bursts and Cosmology

The unrivalled, extreme luminosities of gamma-ray bursts (GRBs) make them the favored beacons for sampling the high redshift Universe. To employ GRBs to study the cosmic terrain -- e.g., star and galaxy formation history -- GRB luminosities must be calibrated, and the luminosity function versus redshift must be measured or inferred. Several nascent relationships between gamma-ray temporal or spectral indicators and luminosity or total energy have been reported. These measures promise to further our understanding of GRBs once the connections between the luminosity indicators and GRB jets and emission mechanisms are better elucidated. The current distribution of 33 redshifts determined from host galaxies and afterglows peaks near z ~ 1, whereas for the full BATSE sample of long bursts, the lag-luminosity relation predicts a broad peak z ~ 1-4 with a tail to z ~ 20, in rough agreement with theoretical models based on star formation considerations. For some GRB subclasses and apparently related phenomena -- short bursts, long-lag bursts, and X-ray flashes -- the present information on their redshift distributions is sparse or entirely lacking, and progress is expected in Swift era when prompt alerts become numerous.Comment: Invited talk given at the JENAM 2003 Minisymposium on Physics of Gamma-Ray Bursts, August 29-30, 2003, Budapest, Hungary; 6 pages, 1 figur

How to Make the Dream Come True: The Astronomers' Data Manifesto

Astronomy is one of the most data-intensive of the sciences. Data technology is accelerating the quality and effectiveness of its research, and the rate of astronomical discovery is higher than ever. As a result, many view astronomy as being in a 'Golden Age', and projects such as the Virtual Observatory are amongst the most ambitious data projects in any field of science. But these powerful tools will be impotent unless the data on which they operate are of matching quality. Astronomy, like other fields of science, therefore needs to establish and agree on a set of guiding principles for the management of astronomical data. To focus this process, we are constructing a 'data manifesto', which proposes guidelines to maximise the rate and cost-effectiveness of scientific discovery.Comment: Submitted to Data Science Journal Presented at CODATA, Beijing, October 200

Are extremely luminous far-infrared galaxies the result of merging quasar cores

Extremely Luminous far-infrared galaxies (ELFs) are a class of galaxy discovered independently by several groups. The class is characterized by a quasar-like total luminosity (10(exp 11) to 10(exp 13) solar luminosity) which is radiated almost entirely in the far-infrared. It has been suggested that obscured quasar cores may be responsible for generating this luminosity. Here the author demonstrates that ELFs appear in several guises which can be characterized by the number of quasar cores they contain (zero, one or two). The author develops a unified model to account for these differences

Wurdi Youang: an Australian Aboriginal stone arrangement with possible solar indications

Wurdi Youang is an egg-shaped Aboriginal stone arrangement in Victoria, Australia. Here we present a new survey of the site, and show that its major axis is aligned within a few degrees of east-west. We confirm a previous hypothesis that it contains alignments to the position on the horizon of the setting sun at the equinox and the solstices, and show that two independent sets of indicators are aligned in these directions. We show that these alignments are unlikely to have arisen by chance, and instead the builders of this stone arrangement appear to have deliberately aligned the site on astronomically significant positions.Comment: Accepted by Rock Art Researc