Peter Wilkinson

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• Peter Wilkinson
• University of Manchester
• Jodrell Bank Observatory
• Oxford 7 November 2002

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Why is radio astronomy important?

• Diagnostic of matter in different phases e.g.
  synchrotron radiation, maser emission as well as
  bremsstrahlung from thermal gas.

• Penetrates dust/gas which absorbs scatters
  in most other wavebands.

• Information on cosmic magnetic fields

• Highest resolution images in all astronomy

Provides unique information about the Universe !
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Radio telescopes make discoveries!
Cosmic Microwave Background
And have set a major part of the current agenda !
Quasars and radio galaxies
Cosmological evolution of radio sources
Gravitational lenses
Jets and super-luminal motions
Dark matter in spiral galaxies
Strong magnetic fields near the Galactic Centre
Interstellar molecules and GMCs
Masers and megamasers
Mass of the central object in an AGN
Pulsars and association with supernovae
Gravitational radiation loss in a binary pulsar
First extra-solar planetary system
GR time delay by planetary radar
Slow rotation rate of Venus spin-orbit locking
of Mercury
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60 years of radioastronomy shows
Discovery can be planned
explore new regions of parameter space
But resolution is required to avoid confusion
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How did the SKA vision arise?
A Universe of hydrogen gas
A Universe of stars
A very different view -- but HI signal is weak !
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The original SKA vision imaging galaxies in HI

with lt1 resolution
NGC 4151 VLA 18 hours
current state-of-the-art
HI at 5 arcsec resolution
(Image from Mundell et al.)
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SKA is the next major step in long-term advance
of radio astronomy sensitivity..


VLA and Arecibo were such large advances that
collecting area unchanged for decades !
Need technology shift to progress !

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History milestones

• 1991 First papers IAU Colloquium 161
• - The Hydrogen Array P. Wilkinson
• 1994 URSI---IAU Large Telescope WG formed
• 1997 Straw Man Specifications Defined
• 19972001 Workshops in Australia, Canada,
  Netherlands, UK, USA
• 1999 First Science Case Document
• 2000 International SKA Steering Committee
• 2000 International MOU signed at IAU Manchester
• 2002 First Director appointed (R. Schilizzi)

SKA was born global!
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SKAs basic specifications

• Sensitivity 50--100x VLA at same wavelength
  ?Brightness sensitivity 1K

Huge change for radioastronomy

• Frequency coverage 150 MHz to 22 GHz

Huge advantages for SKA

• Field-of-view gt1 square degree

• Max. Resolution lt0.1 arcsec to exceed
• HST, NGST, ALMA

The Worlds Premier Imaging Instrument !
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SKAs 10 (minimum) field-of-view for surveys
and transient events in 106 galaxies !
SKA 20 cm
15 Mpc at z 2
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One configuration concept..
Not a single 1 km square aperture !
a wide range of baselines
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Achieving the SKA vision

• The SKA idea is a powerful spur to
  development of radical new ideas in many aspects
  of radio astronomy technology

SKA forerunners will be major instruments in
their own right.
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Achieving the SKA vision

• Reduce overall cost per m2 of collecting area
  by a factor 10 cf. current arrays

While

• Maximising flexibility of design

And

• Minimising maintenance/running costs

?Take advantage of massive industrial RD in
fibre optics and electronics industries
(Moores Law to 2015) for transport and
handling of data
? Develop innovative new concepts for collectors
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China KARST Canada LAR US Large-NSmall-D Aus
tralia Luneburg Lenses Netherlands phased array
Australia Cylindrical Telescopes
India Preloaded parabolas
(UK Phased Array)
All would work now studying relative
cost/performance (White Papers issued for
each concept in 2002)
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Large-N Small-D ConceptPrototype The Allen
Telescope Array

• UCB, SETI Institute
• 100m equivalent
• 350 x6.1 m parabolas
• 1--11 GHz (simultaneously)
• Complete 2006

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SKA poster (multi-beams)
Phased arrays offer many beams
great flexibility
Many targets/users
Interference rejection
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Phased array concept
Basic idea replace mechanical pointing beam
forming by electronic means
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Phased array antenna panels
Making up one of the SKA stations
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Proposed UK SKA Demonstrator
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SKA prototyping..
Allen telescope Array -- under construction
Large Adaptive Reflector aerostat focus
suspension
testing
Luneburg Lenses element RD underway
-- using array feeds
KARST focus suspension testing
Phased arrays individual element RD mature
-- European FP6 proposal
(Netherlands/UK/Italy)
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SKA International Organization

• International SKA Steering Committee
• 18 members from 11 countries
• Chair 2003 Tarter vice-chair Butcher
• Wilkinson Diamond from UK
• Ethos is Inclusivity and to reach global
• consensus on SKA solution
• Focus for strategic planning
• Protocol for making international decisions
• Planning international organisation structure
• Oversight of all other committees and Director
• Concept and site selection (radio quiet zone!)

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SKA International Organization

• Engineering Management Team
• Engineering strategy
• Scrutiny/improvement of concepts
• Science Advisory Committee
• Establishing science priorities
• Chair Carilli Vice-Chair Rawlings
• Site Evaluation and Selection Committee
• Establishing objective siting criteria
• 7 countries expressed interest in hosting SKA
• Ranking final site proposals

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ISSC SKA planning schedule

• 2002 Design concept white papers
• 2002 Director Appointed Management plan with
  ISSC
• 2003 Updated design concept white papers
• 2003 White papers on possible locations
• 2004 Updated white papers on locations
• 2005 Choice of SKA location
• 2005 Full Proposals for designs to ISSC
• 2007 SKA facility definition (may merge
  designs)
• 2010-12 SKA construction begins ?
• 2015-17 SKA completed ?

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SUMMARY

• Will provide unique
• science (today!)

• Could be built now

• Cost driving search
• for innovative
• technological solutions

• Prototyping underway

• Globally-based
• planning started

• Plenty of chance to
• contribute to the debate