32,210 research outputs found
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
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
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 (Jy/bm rms) radio
continuum survey of the entire Southern Sky at 1.4 GHz, extending as far North
as +30 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
Bulk and Edge excitations in a quantum Hall ferromagnet
In this article, we shall focus on the collective dynamics of the fermions in
a quantum Hall droplet. Specifically, we propose to look at the
quantum Hall ferromagnet. In this system, the electron spins are ordered in the
ground state due to the exchange part of the Coulomb interaction and the Pauli
exclusion principle. The low energy excitations are ferromagnetic magnons. To
provide a means for describing these magnons, we shall discuss a method of
introducing collective coordinates in the Hilbert space of many-fermion
systems. These collective coordinates are bosonic in nature. They map a part of
the fermionic Hilbert space into a bosonic Hilbert space. Using this technique,
we shall interpret the magnons as bosonic collective ex citations in the
Hilbert space of the many-electron Hall system. By considering a Hall droplet
of finite extent, we shall also obtain the effective Lagrangian governing the
spin collective excitations at the edge of the sample.Comment: Plain TeX 18 Pages Proceedings for the Y2K conference on strongly c
orrelated fermionic systems, Calcutta, Indi
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