The Square Kilometre Array: an update Steve Rawlings UoOxford and PrepSKA Coordinator Richard Schilizzi SKA Program Development Office Japan, November 2010

A Global Collaboration Science SKA Science & Engineering Committee Policy Agencies SKA Group Coordination SKA Program Development Office

processor

The SKA Concept a large radio telescope for transformational science  ~1 million m 2 collecting area distributed over a distance of 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: SKA 1 and SKA 2 providing  >>10-times (~10 2 ) x sensitivity of any previous telescope  >>1000-times (~ ) x the mapping speed

SKA Phases  Construction will proceed in two phases: SKA 1 and SKA 2 SKA 1 (cost ~€350m) will be a subset of SKA 2 (additional cost ~€1.2B) : low-frequency ( 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 SKA 1 before 2020

Great Observatories for the coming decades ALMA JWST IXO SKA E-ELT

ROADMAPS Europe AstroNet SKA 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 ( ) - future organisation & governance for pre- construction phase ( ) - pre-construction funding - site decision Key Period

SKA Key Science Drivers ORIGINS  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 (SKA 1 ) 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 Array Technical Requirement Snapshot Wavelength (Frequency) 3 cm–4 m (0.07–10+ GHz) SensitivityA eff /T sys ~ (10 nJy, 1000 h) Field of view 1 deg 2 or larger 1 GHz) Survey speed ~ deg 2 m 4 K  2 (100 Gpc 3 survey of H I to z > 1.5)

Baseline Design for SKA 1 1) 1) Low frequency array for 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 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 SKA 1 baseline design Single pixel feed Central Region

Advanced Instrumentation  Further development of innovative wide-field “radio camera” technologies at mid-frequencies  potential for enhancing SKA 1 and be a major part of SKA 2 dense aperture array (FoV ~ 200 deg 2 ) phased array feeds (PAFs) on the dishes (FoV ~ 30 deg 2 )  Decision in 2016

250 Dense Aperture Arrays 3000 Dishes Wide Band Single Pixel Feeds Phased Array Feeds 250 Sparse Aperture Arrays 3-Core Central Region SKA 2 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= )  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 ( MW) ongoing verification programs INDUSTRY ENGAGEMENT IS CENTRAL TO THE SKA (see Diamond talk)

SKA System Design ( ) 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, APERTIF

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 array EMBRACE 2-PAD FP6- SKADS

Fiber optic transmission Signal transport, signal processing Pawsey Centre Petascale System 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 Site characterisation Site selection criteria established Site evaluation  Physical requirements Extremely radio quiet environment At least 3000 km in extent Low ionospheric turbulence Low tropospheric turbulence  Two candidates short-listed in 2006  Site selection process decision RFI 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 2011 WPs 1-2 by 31 March 2012

Current Governance

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 Technical telescope system design and cost detailed design & pre-construction phase Phase 1 construction 2016Advanced Instrumentation Program decision Phase 2 construction 2020  full science operations with Phase  full science operations with Phase 2 Programmatic 2011 establish SKA organisation as a legal entity 2012site selection 2014construction funding approved for Phase 1 (350 M€, 2007) 2017construction funding approved for Phase 2 (1.2 B€, 2007)

Further information

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)

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) 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 Telescope Expanded 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