The Square Kilometre Array: an update

Steve Rawlings UoOxford and PrepSKA

CoordinatorRichard Schilizzi

SKA Program Development Office

Japan, November 2010

A Global Collaboration

Science SKA Science & Engineering Committee

Policy Agencies SKA Group

CoordinationSKA Program Development Office

processor

The SKA Concept a large radio telescope for transformational science

~1 million m2 collecting area distributed over a distance of 3000+ km but with ~50% of collecting area in a compact (~5 km diameter) core

Operating as an interferometer at frequencies from 70 MHz to at least 10 GHz (4m-3cm), with at least two detector technologies: aperture arrays and dishes

Connected to a hierarchical processing system via optical fibre network, and a green-computing icon

Phased roll-out: SKA1 and SKA2

providing >>10-times (~102) x sensitivity of any previous

telescope>>1000-times (~104-6) x the mapping speed

SKA Phases

Construction will proceed in two phases: SKA1and SKA2

SKA1 (cost ~€350m) will be a subset of SKA2

(additional cost ~€1.2B) : low-frequency (70-450 MHz) aperture array with >10% of the final sensitivity, plus dishes (0.45->10 GHz) with ~10% of the final sensitivity

Breakthrough science observations possible with SKA1 before 2020

Great Observatories for the coming decades

ALMA

JWST

IXO

SKA

E-ELT

ROADMAPS

Europe AstroNetSKA and E-ELT equally high priority for ground-based large-scale projects

US Decadal Review SKA represents the “long-term future for radio astronomy”. Mid-decade review opportunity for further funding

Australia Decadal Plan: Pathway to SKA remains #1 priority for radio astronomy in Australia. €200M in investment in radio astronomy infrastructure/capability.

African Union Heads of State acknowledge importance of SKA in the development of knowledge-based economies and driving HCD programs. South Africa is spending €200M on radio astronomy.

Project Status

SKA project is evolving quickly- significant investments in tech. verification

programs, pathfinders & precursors - government ministries & funding agencies are engaged

Key decisions coming up (2010-12)- future organisation & governance for pre-

construction phase (2012-15)- pre-construction funding- site decision

Key Period

SKA Key Science DriversORIGINS

Neutral Hydrogen in the Universe from the Dark Ages to the Epoch of Re-ionisation to now

When did the first stars and galaxies form?How did galaxies evolve?Dark Energy, Dark Matter, Neutrino masses

Cradle of Life: protoplanetary disks, exoplanets

FUNDAMENTAL FORCES

Pulsars, General Relativity & gravitational waves, Gravitational Wave Telescope, Quantum Gravity

Origin & Evolution of cosmic magnetism

TRANSIENTS (NEW PHENOMENA)

Science with the Square Kilometre Array(2004, eds. C. Carilli & S. Rawlings, New Astron. Rev., 48)

Key Science for Phase 1 (SKA1)

ORIGINS

Neutral Hydrogen in the Universe from the Dark Ages through the Epoch of Re-ionisation to now

When did the first stars, galaxies and black holes form?How did they re-ionize the Universe?How did Hydrogen settle into

FUNDAMENTAL FORCES

Pulsars, General Relativity & gravitational waves

Science with the Square Kilometre Array(2004, eds. C. Carilli & S. Rawlings, New Astron. Rev., 48)

Square Kilometre ArrayTechnical Requirement

SnapshotWavelength(Frequency)

3 cm–4 m(0.07–10+ GHz)

Sensitivity Aeff/Tsys ~ 10000

(10 nJy, 1000 h)

Field of view

1 deg2 or larger(@ 1 GHz)

Survey speed

~ 1010 deg2 m4 K2

(100 Gpc3 survey of H I to z > 1.5)

Baseline Design for SKA1

1) 1) Low frequency array for 70-450 MHz for measurements of Dark Ages, Epoch of Re-ionisation and Hydrogen in the distant universe

2) 2) Dish array with single pixel feeds for 0.45-3 GHz

for pulsar timing tests of strong gravity and gravitational waves, and Hydrogen in the nearby universe

250 Dishes

50 Sparse Aperture Arrays

Artist renditions from Swinburne Astronomy Productions

SKA1 baseline design

Single pixel feed

Central Region

Advanced Instrumentation

Further development of innovative wide-field “radio camera” technologies at mid-frequencies

potential for enhancing SKA1 and be a major part of SKA2

dense aperture array (FoV ~ 200 deg2)

phased array feeds (PAFs) on the dishes (FoV ~ 30 deg2)

Decision in 2016

250 Dense Aperture Arrays

3000 Dishes

Wide B

and Single

Pixel F

eeds

Phased A

rray

Feeds

250 Sparse Aperture Arrays

3-Core Central Region

SKA2 including AIP technologies

Artist renditions from Swinburne Astronomy Productions

SKA is driving development of new science & technical solutions

Dishes, feeds, receivers (N=3000) Aperture arrays (N=250, n=104-5) Signal transport (800 Tbit/s) Signal processing (exa-MACs) Software engineering and algorithm

development High performance computing (exa-flop

capability) Data storage (exa-byte capacity) (Distributed) power requirements (50 -100

MW)

ongoing verification programs

INDUSTRY ENGAGEMENT IS CENTRAL TO THE SKA (see Diamond talk)

SKA System Design (2007-2012)Contributing programs (70 fte/yr)

EC FP6 SKA Design Study (SKADS) EC FP7 Preparatory Phase (PrepSKA) US Technology Development Program “Precursor” telescopes on the candidate

sites: ASKAP, MWA (AU), MeerKAT (SA) “Pathfinder” telescopes like LOFAR, APERTIFTelescope

Dish WBSPF

Receivers

SKA User System

Dish Array

Sparse AAArray (Low)

Dense AAArray

Receptors

Feed elements

LNA

People L6System

L7User System

L5Elements

L4Sub systems

L3Assemblies

L2Sub-assemblies

L1Components

Beamformer

Cryo Feed

L0Parts

PAF

LNA

Receptors

Feed elements

LNA

Beam former

Beam management

Beam management

Sparse AAArray (High)

Receptors

Feed elements

LNA

BeamformerBeam

management

To Figure

B

Facilities L6System

L7User System

L5Elements

L4Sub systems

L3Assemblies

L2Sub-assemblies

L1Components

L0Parts

Power Infra-structure

STaN

Operations and Maintenance

Centre(s)

Regional Centres

Regional Engineering

Centres

Core site

Central site

Off site

SupportVisitor centre

Support HQSupport

Trenches RoadsAntenna

foundations

Core site

Central site

Outlying stations

Core site

Central site

Outlying stations

Water FencesGrid Backup Alternative Stores Workshops Offices

Computing and Software

From Figure

A

Signal Processing

Facility

SignalProc

Channeliser and

Correlator

Non visibility

processor

Baseline design component: Sparse aperture arrays for the lowest

frequencies

LOFAR (Netherlands et al)

MWA (USA, Australia)

Baseline design component: Dishes + single pixel feeds

MeerKAT

CART (Canada)

10 m composite prototype

ATA (USA)

42x6m hydroformed dishes

36x12m panel dishes

ASKAP (Australia)

MeerKAT (South Africa)64x13.5-m composite dishes

Advanced Instrumentation Program:

dishes+multi-pixel feeds

DRAO Canada

APERTIF (Astron, NL)

ASKAP

chequer board

array

Advanced Instrumentation Program: dense

aperture arrayEMBRACE

2-PAD

FP6-SKADS

Fiber optic transmission

Signal transport, signal processing

Pawsey Centre

PetascaleSystem

ASKAP

SKA phase 1

SKA phase 2

ASKAP dev cluster

NCI Altix tests

Note that Flops numbers are not achieved - we actually get much lower efficiency because of memory bandwidth - so scaling is relative

SDB

SKA Site

2010 2011 2012Site characterisation

Site selection criteria established Site evaluation

Physical requirementsExtremely radio quiet environmentAt least 3000 km in extentLow ionospheric turbulenceLow tropospheric turbulence

Two candidates short-listed in 2006 Site selection process

decisionRFI measurements in progress

South Africa + 7 countries

PrepSKA: 7 work packages

WP1 PrepSKA management (STFC, U Oxford, U Manchester)WP2 Costed telescope design (SPDO)WP3 Further site characterization in Australia+NZ

and Southern Africa (SPDO)WP4 Governance (NWO, NL)WP5 Procurement and involvement of industry (INAF, Italy)WP6 Options for funding (STFC, UK)WP7 Impact on broad government priorities (U Manchester)

WPs 3-7 will be completed by 31March 2011WPs 1-2 by 31 March 2012

Current Governance

Contributions Audit Committee

(CAC)

Membership Committee

(MC)

International Engineering Advisory Committee

(IEAC)

SKA Science andEngineering Committee

(SSEC)

Executive Committee(XC-SSEC)

SKA Program Development Office

(SPDO)

Working Groups (x5)

PrepSKA WP2Lead Institutions

(x10)

PrepSKA WP2Supporting Institutions

(x6)

Task Forces(x14)

Science Advisory Committee

(SAC)

Agencies SKA Group

Funding agencies and governments from 12 countries (chair: UK Science and Technical Facilities Council)

Aim is to deliver a Joint Agreement on the Implementation of the SKA in 2011/12

Work streams Pre-construction Funding and Interim Governance Site selection process

Joint ASG-SSEC Working Group to establish selection criteria

Schedule for the SKA

Technical2008-12 telescope system design and cost 2013-15 detailed design & pre-construction phase2016-19 Phase 1 construction2016 Advanced Instrumentation Program

decision2018-23 Phase 2 construction 2020 full science operations with Phase 12024 full science operations with Phase 2

Programmatic2011 establish SKA organisation as a legal entity2012 site selection2014 construction funding approved for Phase 1

(350 M€, 2007)2017 construction funding approved for Phase 2

(1.2 B€, 2007)

Further informationwww.skatelescope.org

SKA Precursors

Australian SKA Pathfinder (ASKAP)Allen Telescope

Array (ATA)

Arecibo

Very Long Baseline

Array

Green Bank TelescopeExpanded Very

Large Array

Karoo Array Telescope

(meerKAT, ZA)

SKA Precursors

Australian SKA Pathfinder (ASKAP)Allen Telescope

Array (ATA)

Arecibo

Very Long Baseline

Array

Green Bank TelescopeExpanded Very

Large Array

Karoo Array Telescope

(meerKAT, ZA)

Meter-wavelength instruments

• Epoch of Reionization

• Sparse arrays

• Signal transmission

• Processing and data management

SKA Precursors

Australian SKA Pathfinder (ASKAP)Allen Telescope

Array (ATA)

Arecibo

Very Long Baseline

Array

Green Bank Telescope

Expanded Very Large Array

Karoo Array Telescope

(meerKAT, ZA)

Large-Number–Small-Diameter Arrays

• Galaxy Assembly & Evolution, Gravitational Physics, Dynamic Radio Sky, …

• Field of view expansion

• Signal transmission

• Processing and data management

• Novel antenna construction methods

• Wide-band feeds

SKA Precursors

Australian SKA Pathfinder (ASKAP)Allen Telescope

Array (ATA)

Arecibo

Very Long Baseline

Array

Green Bank TelescopeExpanded Very

Large Array

Karoo Array Telescope

(meerKAT, ZA)

Existing facilities

• Epoch of Reionization, Galaxy Assembly & Evolution, Gravitational physics, Dynamic Radio Sky, …

• Wide band feeds

• Field of view expansion

• Signal transmission

• Processing and data management