The Square Kilometre Array

Transcription

1 Evan Keane, Anna Bonaldi, Tyler Bourke, Robert Braun ECT, Trento, Italy Oct. 9, 2017 The Square Kilometre Array Jeff Wagg SKAO UK

2 2020 and beyond: A multi-wavelength view of the Universe E-ELT optical/ir λ TMT LSST James Webb Space Telescope Programme approved λ LMT due for launch in 2019 ALMA: mm/submm Chajnantor 5000 m Cycle 5 FAST EUCLID: ~ 1B, launch 2020 SKA phase 1 and 2 Inaugurated on 13 th March 2013 λ Footer text

3 SKA1 LOW SKA phase 1 SKA1 MID Both telescopes will have pulsar search and timing capabilities

4 The Science Working Groups Astrobiology ( The Cradle of Life ) - Working Group Chairs: Andrew Siemion (US) and Di Li (China) Extragalactic Continuum - Working Group Chairs: Minh Huynh (AU) and Rosella Cassano (IT) Cosmic Magnetism - Working Group Chairs: Ann Mao (NZ) and Russ Taylor (SA) Cosmology - Working Group Chairs: Mario Santos (SA and PT) and Xuelei Chen (China) Epoch of Reionisation & the Cosmic Dawn - Working Group Chair: Jonathan Pritchard (UK) Extragalactic Spectral Line (non-hi) - Working Group Chairs: Francoise Combes (FR) and Rob Beswick (UK) HI Galaxies - Working Group Chairs: Erwin de Blok (SA) and Martin Meyer (NL) Our Galaxy - Working Group Chairs: Grazia Umana (IT) and Mark Thompson (UK)

5 The Science Working Groups Astrobiology ( The Cradle of Life ) - Working Group Chairs: Andrew Siemion (US) and Di Li (China) Extragalactic Continuum - Working Group Chairs: Minh Huynh (AU) and Rosella Cassano (IT) Cosmic Magnetism - Working Group Chairs: Ann Mao (NZ) and Russ Taylor (SA) Cosmology - Working Group Chairs: Mario Santos (SA and PT) and Xuelei Chen (China) Epoch of Reionisation & the Cosmic Dawn - Working Group Chair: Jonathan Pritchard (UK) Extragalactic Spectral Line (non-hi) - Working Group Chairs: Francoise Combes (FR) and Rob Beswick (UK) HI Galaxies - Working Group Chairs: Erwin de Blok (SA) and Martin Meyer (NL) Our Galaxy - Working Group Chairs: Grazia Umana (IT) and Mark Thompson (UK)

6 The Science Working Groups Pulsars ( Strong field tests of gravity ) - Working Group Chairs: Ingrid Stairs (CA) and Andrea Possenti (IT) Solar, Heliospheric and Ionospheric Physics - Working Group Chairs: Divya Oberoi (IN) and Eduard Kontar (UK) Transients - Working Group Chair: Michael Rupen (CA) and J.-P. Macquart (AU) 135 chapters 2000 pages 1200 authors 9 kg

7 group membership Pulsar science working group current chairs: A. Possenti (IT), I. Stairs (CA) Tier 1: Buchner, Champion, Deller, Gupta, Han, Hobbs, Janssen, Karastergiou, Kramer, McLaughlin, Stappers, van Straten, Theureau Tier 2: many people see: Footer text

8 Pulsar surveys and timing cosmic lighthouses masses: ~1.4 M within 20km B ~ Gauss periods: 1.4ms to 8.5s SKA1-LOW: <350 MHz Surveys for pulsars out of the Galactic plane discovery of exotic pulsars and binaries: PSR-BH - ~16,000 normal psrs (7000 LOW) - ~2,300 ms psrs (900 LOW) - ~100 relativistic binaries - first pulsars in Galactic Centre - first extragalactic pulsars Current estimates are that 50% of the Galactic population will be accessible with SKA1 (Cordes et al. 2004; Smits et al. 2009; Kramer & Stappers 2015; Keane et al. 2015; Pulsar SWG)

9 Pulsar surveys and timing: testing general relativity correlation between msp timing residuals prediction: Hellings & Downs 1983 Figure: Hobbs Figure: Champion millisecond pulsars can be very precise astrophysical clocks, eg: PSR B , period = / ms SKA1 is guaranteed to detect the nhz gravitational wave background

10 Gravitational Wave studies using Pulsars D.Champion Janssen ea 2015 Discoveries with SKA1 (SMBH mergers, Primordial GWs) GW astronomy with SKA2 (discrete sources)

11 SKA global community Australia (DoI&S) Canada (NRC-HIA) China (MOST) India (NCRA/DAE) Italy (INAF) Netherlands (NWO) New Zealand (MED) South Africa (DST) Sweden (Chalmers) UK (STFC) Others? Spain, Portugal, France, Malta all strongly interested. Japan, Brazil, Switzerland? (Germany out, back in later?) 1M Euro buy in, plus % contributions based on IAU membership

12 Negotiations to establish SKA Inter-Governmental Organisation. Text of Convention and protocols now agreed Plan to initial documents in October 2017 Ministerial signing ceremony in December 2017 Transition planning underway 12

13 SKA global community Italy: LFAA, TM CsP, DsH SKA telescope sites South Africa Australia

14 SKA site selection South Africa SKA1 telescope sites Australia

15 SKA1 sites

16 SKA Phase 1 3 sites (AUS, RSA, UK-HQ) 2 telescopes (LOW, MID) one Observatory (SKAO) Construction Cost-cap: 675M Construction: SKA1-Low: ~131,000 low-freq dipoles, MHz 65 km baselines 110 MHz) Murchison, Western Australia SKA1-Mid: ~200 x 15m dishes, (24) GHz 150 km baselines 1.7 GHz; GHz) Karoo, South Africa

17 SKA Phase 1 Karoo, South Africa

18 SKA1 Bands and Spectral Resolution Current Band definitions and Bandwidths: LOW: 50 to 350 MHz Full instantaneous MID Band 1: 0.35 to 1.05 GHz Full instantaneous MID Band 2: 0.95 to 1.76 GHz Full instantaneous MID Band 5a: 4.6 to 8.5 GHz 2 x 2.5 GHz (dual polarisation) MID Band 5b: 8.3 to 15.3 GHz 2 x 2.5 GHz (dual polarisation) 55.5k channels maximum across band - LOW Zoom modes: Four zoom-windows available, bandwidths 4 MHz, 8 MHz,, 256 MHz 16,384 channels maximum in any zoom window. Continuum with 1 MHz channels also provided. Tyler Bourke

19 Appendix 1 Paper for Approval Design Baseline / Deployment Baseline Design Baseline Deployment Baseline Design vs. Deployment Baseline June 2017 view Re-instatement + means add to system SKA1-Mid No. dishes dishes at 150 km Max. Baseline 150 km 120 km + infra to 150 km Band 1 Feeds Band 1 Feeds for 3 dishes Band 2 Feeds Band 2 Feeds for 3 dishes Band 5 Feeds Band 5 feeds Pulsar Search 500 nodes 375 nodes +125 nodes (PSS) SKA1-Low No. stations stations (18 stns at 49 & 65 km) Max. Baseline 65 km 40 km +infra to 65km Pulsar Search 167 nodes 125 nodes +42 nodes Common Compute Power 260 PFLOPs 50 PFLOPs +210 PFLOPs Outcome of July 2017 SKA Board Meeting Design One of Baseline the main issues for reinforced which CDRs during this will work be was undertaken the current funding is unchanged and Deployment membership of Baseline the Consortia. is It scoped is clear that for the cost-capped funding for future extensions Construction to budget consortium agreements is under thre at; in addition, some members are finding it difficult to Further extend analysis due to other of pressures. Low B Max underway Re-instatement of HPC and PSS already part of Operational budget Re-instatement commitment for all items as soon as funding permits The paper follows the instruction to design a system that can be built with in the Cost Cap, although the work indicates where further reductions could be made. However, if funds above the Cost Cap were available, either through additional funding by Members or by new Members joining, the paper includes outline plans on how we would re-implement the reductions we have chosen and thereby reinstate scientific capabilities.

20 SKA1 Pulsar search capabilities Real-time search capability on both Low and Mid 1500 (500) tied-array power beams on Mid (Low) Up to 16 sub-arrays Acceleration search: a < 350 m/s 2 && >= 500 DM trials Acc. = 0 && DM < 300 pc/cc Single pulse: DM < 3000 pc/cc Typical T obs ~10 mins/pointing Observe simultaneously with imaging (+ PSR timing) Tyler Bourke

21 SKA1 timing capabilities 16 timing voltage beams (8 on Band 5) Full-polarization, coherent de-dispersion Clock precision: 5 ns (1σ) & 10 ns (1σ) for Mid & Low SKA1-Mid Bands 1, 2 and 5 part of construction budget. Bands designed but not in construction budget Joint cryostat (cooling) with empty slots for Bands 3 & 4. Timing would want to prioritise adding Band 3 (~S-band) Tyler Bourke

22 Other pulsar capabilities Searches with the timing backend possible: dynamic spectrum mode -Basically do not fold, de-dispersion optional Long pointings (e.g. Sgr A*, globular clusters etc.) - these searches are not in real time A straight voltage flow through mode Transient buffers (~30 s Mid, ~15 mins Low) motivated by FRBs but also PSR applications How to time all the discoveries? Impossible!t Tyler Bourke

23 Sensitivity

24 Survey speed

25 Angular Resolution (arcsec) Andrea Isella Ground based telescopes JVLA SMA CARMA/PBI Angular resolution 10 Spitzer CCAT GBT 1 JWST SKA1-MID 0.1 ALMA mas 0.1 mas 1 um 10 um 100 um 1 mm 1 cm 10 cm 1 m 300 THz 30 THz 3 THz 300 GHz 30 GHz 3 GHz 300 MHz

26 Image Quality Comparison Single SKA1-Mid snap-shot compared to combination of snapshots in each of VLA A+B+C+D 26

27 Image Quality Comparison Single SKA1-Low snap-shot compared to LOFAR snap-shot 27

28 Key Science Projects: Next Steps Access Policy from IGO agreement (Q4 2017) Flesh out KSP policy (SKA Ops & Sci Teams) in consultation with community Specifics will require approval by IGO Council (~2019) Further develop SKA Regional Centre concept Centralised resourcing for national / regional KSP pipelines and added value data products Annual KSP workshop (as/if proves useful) 2016 feed-back has been positive Call for KSP Expressions of Interest Opportunity for coordination of proposal teams via Workshop Call for KSP Proposals Bearing in mind that fully commissioned SKA1 is Bearing in mind suitable lead time for survey team organisation & resourcing

29 Critical Design Review Schedule Milestone Date (TBC!!!) AIV CDR close December 2018 CSP CDR close July 2018 DSH CDR close (Bands 1 & 2) March 2019 DSH CDR close (Band 5) April 2019 INAU CDR close July 2018 INSA CDR close July 2018 LFAA CDR close July 2018 SaDT CDR close April 2018 SDP CDR close December 2018 TM CDR close June 2018 System CDR close Q Construction Proposal submission Q Based on frozen requirements (L1 Revision 11) 29

30 Timeline Construction proposal Construction SKA1 Commissioning/Science verification Project momentum excellent: Preliminary Design Reviews completed Critical Design Reviews scheduled IGO convention initialing & signing imminent SKA construction is on the horizon 30

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