1. Peter Wilkinson SKADS Workshop: Paris 10 October 2007 2 nd SKADS Workshop: Introduction “What is it about?” Peter Wilkinson University of Manchester

2. Peter Wilkinson SKADS Workshop: Paris 10 October 2007 The Square Kilometre Array The world’s most exciting astronomy project for the next 20 years… whose “DNA” is European !

3. Peter Wilkinson SKADS Workshop: Paris 10 October 2007 First things…..Hydrogen Provides a different view of the universe....radio astronomy provides the tools to study it HI is principal driver for the size of the SKA and its “focus” frequencies

4. Peter Wilkinson SKADS Workshop: Paris 10 October 2007 Square Kilometre Array But current radio telescopes, based on pre-1980s technology, are not adequate… Science now demands: 1. Large increase in sensitivity  1km 2 (~50 x) –Observe neutral hydrogen throughout the universe 2. Large increase in field-of-view  >30deg 2 (>200x) –Survey entire sky 3. While maintaining a broad frequency range - Maximise science potential - Maximise science potential Discovery Potential = Area X f.o.v. ~ 10000 x better

5. Peter Wilkinson SKADS Workshop: Paris 10 October 2007 Square Kilometre Array Many new possibilities for radio astronomy –Multipixel sensors with wide bandwidths –Far higher data rates and processing power –New methodologies in software engineering –Grid technology –New materials We have the technology to build SKAWe have the technology to build SKA The challenge is to build it at an affordable costThe challenge is to build it at an affordable cost –In close synergy with industry

6. Peter Wilkinson SKADS Workshop: Paris 10 October 2007 Antenna + Single Pixel Feed Antenna + Phased Array/ (Cluster) Feed Aperture Array HPC 0.3 - 1GHz ~ few GHz SKADS

7. Peter Wilkinson SKADS Workshop: Paris 10 October 2007 “Pathfinder” development (~1% SKA) ATA (US): Small Dish + Single Pixel Feed [High ] LOFAR (NL): Dipole Array [Low ] MWA/LWA (US) Aperture Array [Low ] ASKAP (Aus/Ca): Dish + Phased Array Feed [Mid ] MeerKAT (SA): Dish + Single Pixel/Cluster Feed [Mid  High ] Design Studies EU SKADS: Aperture Arrays [Low-mid transition ] US TDP: Dish/Smart Feed [Mid-high transition ] SKA international

8. Peter Wilkinson SKADS Workshop: Paris 10 October 2007 Science Pathfinder Activity ATA KAT ASKAP MWA LOFAR meerKAT USA: TDP

9. Peter Wilkinson SKADS Workshop: Paris 10 October 2007 EC FP7: PrepSKA “PrepSKA” programm covers period 2008-2011 - Central Design and Integration Team (CDIT) coordinating international R&D  needs new national funding for continuation of SKADS R&D after 2009 - Costed System Design - Further site studies - Governance, Legal Framework, Procurement, Funding Model

10. Peter Wilkinson SKADS Workshop: Paris 10 October 2007 Some outcomes from SKA2007 Basic SKA specifications agreed! The SKA will be a continuously evolving telescope The dish specifications will be formulated in mechanical terms, with a view to extending the high frequency limit of “SKA-mid” to 10 GHz Aperture Arrays form part of all current design options up to 500 MHz The large survey speed required for the all-sky HI survey for baryonic oscillations is linked to the maturity of AA technology

11. Peter Wilkinson SKADS Workshop: Paris 10 October 2007 A phased implementation… Costed design 2008-2011 (within PrepSKA) Production readiness phase 2012 Start of construction 2013 Initial focus on SKA-mid frequencies First 10% (Phase 1) complete 2015-2016 – stand alone science case Target completion date of SKA mid+low 2020 Target construction cost (SKA mid + low): 1500 M€ operating costs: ~100 M€/yr

12. Peter Wilkinson SKADS Workshop: Paris 10 October 2007 Aperture Arrays  SKADS Aperture Arrays  SKADS 1980s: Manchester and ASTRON ideas for large collecting area for HI 1990s: ASTRON Phased array R&D programme (van Ardenne) 2002: Thousand Element Array THEA 2003: European R&D planning begins - based on large-scale “Aperture Arrays” 2004: EC FP6 Design Study Programme SKADS proposed 2005: SKADS funding starts in July

13. Peter Wilkinson SKADS Workshop: Paris 10 October 2007 SKADS FP6 SKADS designed as a “complete” programme –Scientific and technical simulations –Basic technology R&D –Practical demonstrators of AAs & electronic beam forming –A costed design for an entire SKA Programme unusual for EC: national >> EC funding –EC funding was the crucial catalyst Now reached the half-way point – assessment time… –This 2-day meeting –The mid-term review by the EC on Friday

14. Peter Wilkinson SKADS Workshop: Paris 10 October 2007 Upcoming European Issues “SKADS in context of PrepSKA” – need to secure funding –overall system design; cost modelling; manufacturability; industry links A big issue: the “minimum capability demonstrator for AAs” Need to prove AA capability in many areas –Achievable system temperature – vital to get below 50K –Calibratability  sidelobes  dynamic range –Environmental robustness on an SKA site Effect of ambient temperature variations Effect of sunlight, dust and water ingress, lighting strike Want a large (5000m 2 ) AA component in early phase SKA

15. Peter Wilkinson SKADS Workshop: Paris 10 October 2007 Now let’ s get down to the details…

16. Peter Wilkinson SKADS Workshop: Paris 10 October 2007 The Hydrogen Array: 1990 The Hydrogen Array: 1990 Radio Interferometry: Theory, Techniques and Applications I AU Coll. 131, ASP Conference Series, Vol. 19, 1991 T.J. Cornwell and R.A. Perley (eds.) THE HYDROGEN ARRAY P. N. WILKINSON University of Manchester, Nuffield Radio Astronomy Laboratories, Jodrell Bank, Macclesfield, Cheshire SK11 9DL, United Kingdom ABSTRACT The time is ripe for planning an array with a collecting area of 1 km 2 (14 times larger than Arecibo and 75 times larger than the VLA). In view of its major astronomical target I have dubbed this concept 'The Hydrogen Array', although 1µJy continuum sources will also be reliably detected. I present some initial thoughts about the issues involved.

17. Peter Wilkinson SKADS Workshop: Paris 10 October 2007 Review Hi-freq SKA Design Production Readiness Review SKA-mid+low 06 |08 |10 |12 |14 |16 |18 |20 |22 |24 | Concept Des’n System Design Prod’n Readiness & System Verif’n SKA mid +low Construction & Commissioning SKA-hi Construction Sites short-listed EC-FP7: PrepSKA System design Funding Governance Site Seln Initial SKA specs External Engineering Review of design Reference Design selected Pathfinder Suite Construction Early Science SKA mid+low SKA-mid+lowComplete Site Select SKA Pathfinders Complete SKA timeline Concept design for SKA-hi System design SKA-hi Costed SKA low+mid designs complete Pathfinder science