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LOFAR Status

LOFAR Status. Internal review of the project (April-July 2007): Main conclusions: R&D developments in good shape (CS1 results) Development costs in line with original estimates Original 77-station LOFAR relied on significant matching from original international partners (e.g. ATNF, MIT, NRL)

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LOFAR Status

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  1. LOFAR Status • Internal review of the project (April-July 2007): • Main conclusions: • R&D developments in good shape (CS1 results) • Development costs in line with original estimates • Original 77-station LOFAR relied on significant matching from original international partners (e.g. ATNF, MIT, NRL) • 77 station unrealistic in short-term… • De-scope process initiated - August 2007 • Need for a re-scoped LOFAR presented to NL and international (DE & UK) commiunities • Prof. Ralph Wijers (chairman of NL-ARC) together with the support of the LOFAR project directorate, asked to report to the ASTRON board on: • the extent of the necessary de-scope • the optimal configuration based on (i) the most pessimistic and (ii) a more optimistic scenario • 3 meetings, including an open workshop (17 September 2007)

  2. Wijers’ draft report • Wijers’ draft report presented to the ASTRON board (21 September 2007): • Original LOFAR: • 96 LBA & 96 HBA • HBA ~ 16 m^2 • 32 core stations, 45 outer stations; 77 stations in total • Re-scoped LOFAR: • Core: 96 (48) LBA & 2 x 24 HBA • Outer: 96 (48) LBA + 48 HBA • 25m^2 HBA N.B. Stations smaller but Field of View expanded by x4 • No. of stations reduced: • Minimal (most pessimistic) configuration 36 (18+18) stations • Most optimistic configuration 50 (25+25) station • Build long-baseline stations towards German border

  3. Wijers draft report (cont) Wijers’ draft report presented to the ASTRON board (21 September 2007): • Original LOFAR: • 96 LBA & 96 HBA • HBA ~ 16 m^2 • 32 core stations, 45 outer stations; 77 stations in total • Re-scoped LOFAR: • Core: 96 (48) LBA & 2 x 24 HBA • Outer: 96 (48) LBA + 48 HBA • HBA now 25m^2 N,B, Stations smaller but Field of View expanded by x ~ 4 • No. of NL stations reduced: • Minimal (most pessimistic) configuration 36 (18+18) stations • Most optimistic configuration 50 (25+25) station • Build long-baseline stations towards German border. • International stations remain unchanged in size.

  4. Constraints on rescope • Money: 25 MEUR phase 1 • Rollout Schedule: before end 2009 done • Software = capabilities • Calibrateability • Expandability: (?)0-8 MEUR phase 2, ..... • Eu-LOFAR • Operations: cost control • Other sciences (geo/agro/meteo/....)

  5. LOFAR-ph1 Global • 50%-50% core/outer split in NL, aim for 25+25 • Keep European stations original 96+96 • Make NL stations smaller: • core: 96/48 LBA + 2x24 HBA • outer: 96/48 LBA + 48 HBA • 25 m2 (4x4) HBA tiles • Bias outer stations towards Germany (lopsided configuration)

  6. LOFAR-ph1 rationale - I 50%-50% core/outer split, aim 25+25 • uv-coverage has priority over raw collecting area, both core (EoR, RSM) and outer (resolution, SRV) need to be good  more smaller stations • Below 25+25, good uv-coverage quickly gets harder

  7. LOFAR-ph1 rationale - II Keep European stations 96+96 • Fewer outer baselines: sensitivity very important for calibration • Split-station needs higher data rate and use of larger FOV initially doubtful

  8. LOFAR-ph1 rationale - III NL outer station: 96/48 LBA + 48 HBA • HBA and RCUs are expensive, so reduction most helps more stations • LBA are cheap, hard to add, so put all 96 and use LBL/LBH to connect all, but only 48 can be used. • Select inner/outer 48 • Select ‘minitile sum’ of 2 for better sensitivity • NOTE: 48 has larger FOV!

  9. LOFAR-ph1 rationale - IV NL core station: 96/48 LBA + 2x24 split HBA • LBA same as outer • HBA split in two fields at ends of 100m x 200m field • Better uv-coverage in core • 24-HBA substation has even larger FOV • Price: 2 substation signals out, higher data rate

  10. LOFAR-ph1 rationale - V Maintain long baselines and build lopsided towards Germany • Important for resolution and depth (confusion limit) and connection to E-LOFAR • Lopsided to East gives more weight to long baselines than symmetric distribution around core • Price: more time to fill uv-plane

  11. LOFAR-ph1 Rollout • 20 stations, 13 core + 6 outer + 1 distant outer, by end 2008 • Rest by end 2009, in logistically best order • HBA subCDR and 20-station review should be planned to minimally delay rollout. • Software rollout plan is urgent

  12. LOFAR organisation • ASTRON is the largest partner, assumes the vast majority of risk, provides the expertise and man-power for the development, roll-out and commissioning of LOFAR. • LOFAR Managing Director reports on a daily basis to ASTRON General Director. • Radio Observatory ASTRON will be responsible for LOFAR operations. • Radio Observatory ASTRON will be the international communities contact point for E-LOFAR.

  13. ASTRON / Radio Observatory takes up long-term coordination of LOFAR astronomical exploitation Run as broad common-user observatory, while astronomical user groups focus on their particular science projects. Three-tier allocation of “observing time”: Current LOFAR KSPs given proper recognition: Highly valuable contributions, major undertakings New parties welcomed and encouraged, especially if: Contributing to development of (extended) LOFAR infrastructure Contributing to sustained LOFAR astronomical operations Substantial fraction open to worldwide community. This is vital: To foster the user community For the overall and long-term scientific success Services may be provided for non-astronomical applications, brokered through LOFAR foundation LOFAR Astronomical Exploitation

  14. Astronomical operation of LOFAR and the WSRT in a fully integrated Radio Observatory division Observatory Operations Room in Dwingeloo will be taken into use next month Observatory is interface between R&D and Astronomy (“customer”, “supplier” roles) Observatory contacts for all LOFAR system components New Science Support Group getting established Services may be provided for non-astronomical applications, brokered through LOFAR foundation Evolving Observatory Structure

  15. Minimum critical mass, structure, and composition to allow optimizing: Quality of operations Overall cost Budget now on firm footing Augmentation above minimum critical mass possible in a natural way International share of the operations/costs must be discussed Lessons must be learned for CS1 about best practice operational model Technically: maintenance, operational procedures, documentation Partnerships: RUG/RC, KSP-centres, E-LOFAR, multi-disciplinary aspects, outsourcing Evolving Observatory Structure

  16. The latest commissioning results

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