2 nd SKADS Workshop: Introduction “What is it about?”

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

2. The Square Kilometre Array The world’s most exciting astronomy project for the next 20 years… • whose “DNA” is European !

3. 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. Square Kilometre Array But current radio telescopes, based on pre-1980s technology, are not adequate… Science now demands: 1. Large increase in sensitivity  1km2 (~50 x) • Observe neutral hydrogen throughout the universe 2.Large increase in field-of-view  >30deg2 (>200x) • Survey entire sky 3.While maintaining a broad frequency range -Maximise science potential Discovery Potential = Area X f.o.v. ~ 10000 x better

5. 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 SKA • The challenge is to build it at an affordable cost • In close synergy with industry

6. SKADS Aperture Array HPC 0.3 - 1GHz Antenna + Phased Array/ (Cluster) Feed Antenna + Single Pixel Feed ~ few GHz

7. “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. Science Pathfinder Activity ATA ASKAP MWA LOFAR meerKAT KAT USA: TDP

9. 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. 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. 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. 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. 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. 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 (5000m2)AAcomponent in early phase SKA

15. Now let’ s get down to the details…

16. 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 km2 (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. EC-FP7:PrepSKA System design Funding Governance Site Seln SKA timeline SKA-mid+low Complete Site Select Reference Design selected SKA Pathfinders Complete Initial SKA specs External Engineering Review of design Sites short-listed Pathfinder science Early Science SKA mid+low 06|08 | 10 | 12 |14 | 16 | 18 | 20 | 22 | 24 | Prod’n Readiness & System Verif’n SKA mid +low Construction & Commissioning Concept Des’n System Design Pathfinder Suite Construction Concept design for SKA-hi System design SKA-hi SKA-hi Construction Review Hi-freq SKA Design Production Readiness Review SKA-mid+low Costed SKA low+mid designs complete