The Potential for Astronomy in Antarctica

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The Potential for Astronomy in Antarctica

• Michael Burton

with thanks to Michael Ashley, Jon Lawrence, John
Storey
Image Michael Burton
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Why Antarctica?

• The Antarctic Continent
• Site Conditions
• Astronomical Potential
• Infrastructure and Facilities

Image Michael Burton
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No Penguins!
?
Australian Antarctic Division
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High, Dry and Cold!
Image Michael Burton
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Some myths about Antarctica

• Its completely inaccessible
• Your telescope will blow away
• The conditions make it impossible to work

Image Karim Agabi
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Contour map of Antarctica
South Pole X

• USGS image

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• Dome C

• Mawson

• Davis

• Casey

4.5 hours

• Hobart

• Sydney

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The Antarctic plateau is

• High (3000 4000m)
• Dry (lt250µm ppt H2O)
• Cold (-60? to -90?C)
• Stable (little wind!)
• And offers continuous observing.

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Three Advantages for Astronomy in Antarctica

• Low Water Vapour
• new windows
• reduced emissivity
• Low Temperature
• reduced background
• Low Aerosols
• reduced background
• improved sky stability

The Automated Astrophysical Site Testing
Observatory
Image Michael Burton
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It is so dark that one of our site testing
instruments inadvertently produced a near-IR map
of the Milky Way - with a 3 mm diameter
telescope!
DIRBE (in space)
IRPS (in Antarctica)
The Milky Way at 2.2 microns
See Phillips et al 1999
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Infrared Sky Background
20100 times lower than good temperate sites
Mauna Kea (www.gemini.edu)
South Pole (IRPS/ MISM)
Ashley et al 1996, Phillips et al 1999,
Chamberlain et al 2000
South Pole Teff -40? C, Mauna Kea Teff 0? C
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Summary of the global oceanic aerosol pattern
detected by polar-orbiting satellites between
July 1989 and June 1991

Mid-infrared
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The Water Vapour is 5 timessmaller at the South
Pole
Lane 1998
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The atmospheric transparency and stability in the
sub-mm is the best on earth.
Pole
Chajnator
Mauna Kea
Comparison of South Pole with two other sites.
(Data from Jeff Peterson, CMU)
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Infrared Options for Antarctica

• Sensitivity determined by
• So to make an impact.
• 2.2 to 5 ?m or 8 to 13µm where low temperatures
  and low aerosols suppress thermal background
• 4.7 to 5.5 ?m or 16 to 35 ?m where high
  transmission opens up windows
• With a telescope large enough to realise the
  gain.

? S/N µ D / q . (h t / e)0.5
? Transmission, ? Background, ? Image Size, D
Diameter
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Three More Advantages

• Wide isoplanatic angle
• longer coherence times
• always a star for AO correction!
• Low scintillation
• precision photometry
• Continuous observation
• monitoring
• all year in the thermal IR!

Marks 1999, 2002
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Unlike all other sites, the Antarctic plateau
has no high-altitude turbulence. This has
profound implications for astrometry, photometry
and interferometry.
South Pole SODAR data, showing turbulence
confined to lowest 300 m.
Travouillon et al 2002
900 metres
12 months
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This would be a good place
Image NASA
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The Calmest Place on Earth!
ESO data
Valenziano DallOglio 1999, PASA 16, 167 Dome C
50 1.0 m/s
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Wind Speed Profiles (University of Nice)
Altitude (Km)
Altitude (Km)
Altitude (Km)
Dome C (Dec 2000)
Paranal ESO Chile (1992)
Gemini NOAO Chile (1998)
Agabi and Fossat (2003)
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Atmospheric turbulence
MK
The absence of high-altitude turbulence above the
Antarctic plateau is of profound
importance. Isoplanatic angle 30 times larger
than on Mauna Kea Marks et al, AA Supp
(1998) Marks et al, AA Supp (1999) Marks 2002
SP
SP25
Log Altitude
Turbulence
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The effect of eliminating high-altitude turbulence
Turbulent layer high ? narrow field
Turbulent layer low ? wide field
10 100 times improvement in isoplanatic angle,
scintillation noise, and astrometric error.
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Two More Advantages

• Vast quantities of pure ice
• Muons and neutrino interactions
• High geomagnetic latitudes
• Increased cosmic ray fluxes at low energies

AMANDA drill site
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Focus Areas for Antarctic Telescopes

• Wide-field Thermal Infrared Imaging
• 2m Antarctica 8m Temperate Latitude
• Continuous Observation at 2.4µm
• Background lowest, Source never sets
• Precision Photometry
• Mid-IR Interferometry
• Reduced background, improved phase stability
• Astrometric Interferometry
• Long time period, micro-arcsecond, positions
• Error ? h2 Cn2

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Science Programs

• Star Formation and the Galactic Ecology
• Protogalaxies and Earliest Star Formation
• 2.4µm Cosmological Window, V-L 10
• Micro-lensing towards Galactic Centre
• 2.4µm continuous observation, optical depth
  unity!
• Exo-solar planets
• Precision photometry for planetary occultations
• Stellar seismology and tomography
• Precision photometry, continuous observation
• Galactic and LMC dynamics
• Precision astrometry

Burton et al 2000
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Amundsen-Scott South Pole Station
Images Michael Burton
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Infrastructure to meet all needs!
Images Michael Burton
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Telescopes, Telescopes, Telescopes
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Concordia Station
Nearly Finished!
A permanent, winter station is currently under
construction.
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Tractor and Plane to Dome C
http//sung3.ifsi.rm.cnr.it/dargaud/
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Lunch Time Volleyball at Dome C
Pressure altitude 3600 m Temperature -30oC
Image Patrik Kaufmann
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One HundredDays at Dome C!(see theUNSW
displayby theStarLabPlanetariumin the Expo)
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Further Informationwww.phys.unsw.edu.au/astro

• South Pole Diaries
• Antarctic Picture Gallery
• South Pole Webcam
• The AASTO
• The Douglas Mawson Telescope
• JACARA Bibliography

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Infrared Sky Background

• 20100 times lower than good temperate sites

Chamberlain et al 1999
Ashley et al 1996
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Sensitivity for widefield imaging
Fluxes in Jy / square arcsecond 5 sigma, 1 hour
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The effect of reducing high-altitude wind
Turbulent layer moves slowly

• Phase coherence times increased
• Required adaptive optics bandwidth decreases

10 100 times improvement in sensitivity of
interferometers and AO sensors.