NRAO/Socorro Colloquium Series
Ray Norris
ATNF/CSIRO
ASKAP-EMU: The Challenge of Deep Wide Radio Continnum Surveys
The Australian SKA Pathfinder
(ASKAP) is now in the process of commissioning, and within the year we
hope to start the EMU (Evolutionary Map of the Universe) survey. EMU
will survey three quarters of the sky at 20cm to a sensitivity of 10
microJy, some 45 times deeper than NVSS, to yield a catalogue of 70
million galaxies, for many of which we will also measure spectral
indices and polarisation. EMU differs from previous wide radio surveys
in reaching a sensitivity level at which star-forming galaxies, rather
than AGN, dominate the source counts, and so the science is
qualitatively different, reaching into diverse areas such as cosmology,
galaxy evolution, and Galactic astronomy. However, the challenge of
extracting the science from the data is formidable. For example, only
about 1% of EMU sources will have a spectroscopic redshift, and so we
are exploring new techniques fro measuring the redshift distribution
for an ensemble of radio sources. EMU also has the potential to
discover unexpected new phenomena, as it is observing an unexplored
part of the observational phase space. However, the petabytes of data,
and consequent arms-length access to the data, may prevent an observer
from recognising such discoveries. Unexpected phenomena may lurk in
dark corners of the database that will never be fully explored, and so
remain undiscovered. Can we harness data-mining techniques to help the
intelligent observer search for the unexpected in next generation
surveys such as EMU? I believe we can, and indeed we must if we are to
reap the full scientific benefit of next-generation telescopes.
May 24, 2013
11:00 am
Array Operations Center Auditorium
All NRAO employees are invited to attend via video, available in Charlottesville Room 230, Green Bank Room 137 and Tucson N525.
Local Host: Minnie Mao
