Astronomy Research at the University of Tasmania

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Astronomy Research at the University of Tasmania

• John Dickey
• Head of Discipline in Physics
• University of Tasmania

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• Outline
• 1. Optical Astronomy
• New Planets around Other Stars
• 2. Radio Astronomy
• a. VLBI Earth Orientation Parameters
• b. VLBI The Winds of Titan
• c. Spectroscopy Star Formation in Dark Clouds
• 3. The Future
• a. Pulsars, transients and FPGA boards
• b. Searching for the Epoch of Reionization

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Optical Astronomy New Planets around Other
Stars
Mt Canopus 1 m telescope at night
UTas astronomers John Greenhill Kym
Hill Stefan Dieters in collaboration with
astronomers in Perth, France, US, New Zealand,
Chile, South Africa
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Gravitational Lensing
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• Example of a star field showing a stellar
  microlensing event in progress EROS 2000-BLG-005

Normal brightness
Peak brightness
UT
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Light curve with planetary anomaly-
OB-03-235/MOA-03-53
OGLE alert
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UTas radio astronomers Peter McCulloch Simon
Ellingsen John Dickey Melanie
Johnston-Hollitt Aidan Hotan Jamie
Stevens Ph.D. Students Jamie McCallum, Cliff
Senkbeil, Claire Hotan, Dion Lewis,
(pulsars)
(star formation)
(interstellar medium)
(galaxy clusters)
(pulsars)
(galaxy groups)
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U Tas Radio Telescopes are the Backbone of Very
Long Baseline Interferometry in Australia
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January 14, 2005
ESA-NASA Mission to Saturn Cassini (orbiter)
Huygens (probe)
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1230 UTC
1018 UTC
Parkes, NSW CSIRO - ATNF 64m telescope
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High Altitude Photo of Titans surface showing
rivers, possible lake or ocean (of liquid
hydrocarbons?).
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UTas is a member of the International VLBI Service
The IVS is a collaboration of 29 radio telescopes
that keep track of the Earth Orientation
Parameters, numbers that tell how the earth is
rotating and which way the axis is pointing.
These are used to calibrate GPS and all
other location-finding equipment.
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Stations of the International VLBI Service
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Motion of the earths polar axis (north) measured
on the sky, relative to extragalactic radio
sources. 1 mas 10-9 of a circle
(one 4-millionth of a degree) 3 cm on the
earths surface
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get this data from http//hpiers.obspm.fr/eop
-pc/
The length of a day varies by a few hundred
micro-seconds each day. This is partly
predictable, partly unpredictable.
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A high priority area for Australia is to build up
our geodetic infrastructure. There is a plan to
build several more telescopes, dedicated to VLBI
measurement of location, to establish a national
geospatial reference system. UTas will be a
major partner in this project.
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Infrared Dark Clouds
IRDCs are a new class of interstellar
clouds, recently discovered by the Spitzer Space
Telescope and other far-infrared telescopes in
space.
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GLIMPSE map of the inner Milky Way at 8 micron
wavelength
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map of emission in the NH3 molecule, made at the
ATCA by John Dickey and Ed Churchwell (U.
Wisconsin) 2006
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NH3 spectrum (intensity vs. frequency or Doppler
velocity)
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same spectrum observed from Mt. Pleasant (Hobart)
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Southern Galactic Plane Survey
(SGPS) McClure-Griffiths, Dickey, Gaensler, Green
(2004) Study of the Milky Way at 21-cm
wavelength with Parkes ATCA.
SGPS continuum maps
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The Future Signal Processing Hardware based
on Field Programmable Gate Arrays (FPGAs)
This board has the power of 512 personal
computers, plus clocks, ethernet, memory, 3
FPGAs, and high speed I/O.
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The Square Kilometer Array -- 2015?First the
Mileura Widefield Array
Not a single 1 km square aperture !
a wide range of baselines
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Phased Array
LFD
xNTD
Alternate idea replace mechanical pointing, beam
forming by electronic means
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The Low Frequency Demonstrator (LFD) Webster et
al. (Uni Melbourne) Lynch et al. UWA Lonsdale et
al. (MIT) Dickey et al. UTas Greenhill et al.
(Harvard) Gaensler et al. USyd Briggs et al.
(ANU) CSIRO - ATNF
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The Cosmic Web
Spectra of QSOs show many Ly-a absorption
lines due to low column density H N-body
simulations predict the existence of a
cosmic web Complicated structure of filaments
and sheets of material LFD will detect this
web In HI emission!
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reionization here
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Conclusion UTas Astronomy and Physics Are
Growing!
We need more students please spread the word.
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