Transcript The SKA Design Study “SKADS”

The SKA Design Study
“SKADS”
Peter Wilkinson
University of Manchester
JENAM Liege 6 July 2005
The SKA – A revolution in Astronomy
• the next generation radio telescope for astronomy, STP,
astroparticle physics & fundamental physics
• 50-100 x sensitivity and >105 times the survey speed
of the currently most powerful radio interferometer
• Essential complement to ALMA, ELT, space observatories
• Coordinated internationally from outset
In SKADS Europe is developing the “breakthrough
technologies” for large & multiple fields-of-view
Why do we need a next
generation radio
telescope?
Radio band provides unique information
• From matter in different phases
• Penetrates dust/gas
• Cosmic magnetic fields
• Most accurate clocks
• Highest resolution images
• Access to the fundamental element: via the 21cm line
Radio telescopes make discoveries!
• Cosmic Microwave Background
• Quasars
• Cosmological evolution
• Gravitational lenses
• Superluminal motions
• Dark matter
• Masers
• Pulsars
• Gravitational radiation
• First extra-solar planetary system
but what’s so special
6
2
about 10 m ?
The universe in starlight
… and in 21cm-line of hydrogen
Very different views -- but the hydrogen signal is weak !
(Transition probability for spin-flip about once per million years)
SKA’s sensitivity
SKA
• Detects normal galaxies out to cosmological redshifts
(in HI and continuum)
• All objects detected in other wave bands likely to be
detected and imaged with SKA
• Detects objects not visible in the optical!
Science breadth is staggering!
Five key projects
• Probing the Dark Ages, first black holes & stars
- epoch of reionization: via HI at z = 6 -15
- star forming galaxies: via CO at z = 5 -15
- first AGN: via deep continuum images
• Evolution of galaxies, dark matter, dark energy
- Exquisite power spectrum via HI galaxy surveys
- Compute Universe’s equation of state
- Strength of Dark Energy as fn. of cosmic epoch
- Imaging the Cosmic Web in HI
- Kinematics and environment of galaxies from
z~5 to present via observations of neutral gas
SKA science breadth is
staggering!
• Extreme tests of General Relativity with pulsars and black holes
- large surveys  msec pulsar orbiting BH
- pulsars orbiting close to SMBH in Galactic Centre
- large surveys  msec pulsar timing array for gravitational wave background
• The origin and evolution of cosmic magnetism
- Rotation measures for 108 radio sources
- Deep polarimetric observations of nearby galaxies & clusters
- Connection between magnetic fields and large-scale structure to z>3
• The cradle of life – searching for life and planets
- J=1-0 transitions of amino acids in molecular clouds
- Terrestrial planet formation in circumstellar disks at 0.15 AU resolution
- “Leakage” radiation from ETI transmitters out to 100s pc
+ New discoveries to add those from 20th century radioastronomy
( see New Astronomy Reviews vol 48 December 2004)
Pulsars and GR
FUNDAMENTAL PHYSICS: Pulsar + black hole 
Testing GR to breaking point.
Galaxy Evolution & Cosmology
“baryon wiggles” as f(z)
late universe result of
CMB fluctuations
HI redshift surveys of 109 galaxies (1000times larger than state-of-the-art)
Test Einstein’s ideas for Dark Energy to
destruction.
Epoch of Reionization
lower z
Evolution of hydrogen in the early universe as a
function of redshift (i.e. frequency of HI line)
Needs technology breakthroughs…
• An SKA covering a sub-set of the science goals could be
built now for €5B using current technologies
Challenge: to reduce overall cost per m2 of collecting area to
~€1000/m2 (SKA cost target €1B)
Take advantage of industrial R&D in fibre optics and electronics and
computing for the transport and handling of data
 Develop innovative new collector systems allowing larger fields-ofview for faster surveying
The vision in Europe
• Electronic, phased array-based system
• Provide massive increase in flexibility and data gathering
capability
• Configurable at observer’s will
• Provide a wide range of observing and processing
options to maximise chance of new discoveries
Dramatic paradigm shift for astronomy!
The revolution in radio telescopes
Based on phased arrays of receivers
Focal plane arrays
(radio “cameras”)
MANY STEERABLE
FIELDS-OF-VIEW !
Aperture arrays (“solid state fish-eye
lens” cf. “shaped metal” telescope)
SKADS: catalysed by FP6
8 EU countries: 29 organisations:
: Netherlands coordinates
: UK, France, Italy major contributors
(Australia, South Africa, Canada, Russia)
Main deliverables: establishing science/technical specs
: optimisation of Network architecture
: breakthrough technology R&D
: large (100s m2) “aperture” array EMBRACE
; all-digital dual-pol phased array: 2-PAD
Scale of total programme: ~€38M
EC FP6: €10.44M; national funding ~€28M
SKADS simulations will tell us:
What are the trade-offs between key design
parameters (sensitivity, FOV etc) and key
science ?
– number of FOV vs amount of physical area
( “electronics” vs “metal & concrete” )
May not need 106 m2 at all wavelengths !
Many beams offer great flexibility
SKA poster (multi-beams)
Many targets/users
Interference rejection
SKADS prototype: “EMBRACE” to be built in Netherlands
Small dish + “Smart feed”
• Smart feed based on
SKADS digital phased
array 2-PAD
• SKADS partners include…
• Karoo Array Telescope
(South Africa)
• xNTD array
(Australia)
Two prototypes doing SKA-style
science by 2009
Network structures of the SKA
Station model
Station
processor
• Fully distributed processing
central
processor
• Upgrade via increasing Nb
• Modest data rates
Station
processor
Totally flexible model
• Fully centralised processing
central
processor
• Totally flexible
• High data rates
As computing power grows – so will SKA’s power
Moore’s Law
1000 times more powerful computing even by 2020
 natural upgrade path to more “beams”
 more powerful SKA with little change in hardware
Summary
International SKA access point:
• SKA provides unique
science
• Could be built now
• Cost is driving us to
new technologies
Europe is leading the
way via SKADS
www.skatelescope.org
Timescales for the SKA
• Technology development phase to 2009:
- international selection of collector concept(s) and proceed to final design
- selection of site short list 2006 (Australia, South Africa, China, Argentina)
• Construction phases (~2010 - 2020):
- start with ~10% “pathfinder” (central array)
• Estimated final cost: ~1 B€ is the aim
• ~35% Europe
• ~35% USA
• ~30% Australia, Canada, China, India, Japan, South Africa, ……
SKADS EC Framework 6
Design Study
Signal intensive
Receiving and Collector
Concept,
Station-level Signal
Conditioning
and Processing Architecture
Control
and
Data
intensive
Wide Area Data transport
Network
monitor
software
Data reduction
and Imaging
Central Processor
Computing intensive
Distribution and
Archiving
and
Use by astronomer
Storage intensive