Catherine Cesarsky
Zurich June 11 2018
CTA: 2024
ATHENA:
2028
JWST: 2020
ALMA: operational
SKA: 2025
21st Century
Observatories
E-ELT: 2024
LIGO: operational
VIRGO: operational
Cosmic Dawn(First Stars and Galaxies)
Galaxy Evolution(Normal Galaxies z~2-3)
Cosmology(Dark Matter, Large Scale Structure)
Cosmic Magnetism(Origin, Evolution)
Cradle of Life(Planets, Molecules, SETI)
Testing General Relativity(Strong Regime, Gravitational Waves)
Exploration of the Unknown
Broadest science range of any facility on or off the Earth.
Cosmic Dawn
SKA will observe Hydrogen to make a movie of the Dawn of the Universe
3”
380000 years
Cosmic Dawn: What might SKA observe?
Simulation: ”Swiss cheese effect”. Growing bubbles of ionized material sitting in sea of hydrogen, over ~1 billion years
SKA: Gravity through pulsars
Massive stars > 8Mo
Explode as supernova
Dense core collapsesinto neutron star
Rapidly rotating
Beam of radiation along magnetic axis
Cosmic lighthouses
Extreme matter
Superb natural clocks
Double pulsar
SKA will detect all pulsars in Milky Way
- ~30,000 normal pulsars
- ~2,000 millisecond pulsars
- ~100 relativistic binaries
- pulsar – Black Hole binaries
- first pulsars in Galactic Centre
- first extragalactic pulsars
• Probe General Relativity to its breaking point.
• Direct detection of gravitational waves passing
through the Galaxy
SKA Organisation: 10 countries, more to join
(Simon Berry)
Australia (DoI&S)Canada (NRC-HIA)China (MOST)India (DAE)Italy (INAF)Netherlands (NWO)New Zealand (MED)South Africa (DST)Sweden (Chalmers)UK (BEIS/STFC)
In discussion with :• Germany• France• Portugal• Spain• Switzerland• Japan• Korea
What will SKA be
like?
How were the sites selected?
Consider the expanding Universe…..
Mobile Phone
Aircraft
Digital TV
FM
Cardiff Seminar, 16 May 2018
• Why build the SKA at such remote locations?• at the SKA operating frequencies (0.05 – 15 GHz) radio frequency interference is one of
the biggest concern with respect to data quality
1
1
Karoo SKA site
• Cape Town
SKA site:
• Remote
• Radio Quiet
• Altitude: ~1000m
• Johannesburg
350 MHz to 15.3 GHz
SKA1 –Mid: Layout
13
• 133 SKA 15m dishes
• 64 MeerKAT 13.5m dishes
• Maximum baseline 150 km
• 3 logarithmic spiral arms
SKA1-LOW
60km
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ImageLandsat/Copernicus
ImageLandsat/Copernicus
ImageLandsat/Copernicus
SKA1-Mid
MeerKAT
Karoo Region
South Africa
SKA1 –Mid: Layout
14
• 133 SKA 15m dishes
• 64 MeerKAT 13.5m dishes
• Maximum baseline 150 km
• 3 logarithmic spiral arms
• ~ 50% within ~2 km
randomly distributed
SKA1-LOW
2km
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SKA1-Mid
MeerKAT
Karoo Region
South Africa
Murchison Radio Astronomy Observatory
; size of the Netherlands
50-350 MHz
SKA1 – Low: Layout
16
• 512 aperture array stations
• Maximum baseline 65 km
• 3 modified spiral arms
SKA1-LOW
SKA1 – LOW: Layout
17
• 512 aperture array stations
• Maximum baseline 65 km
• 3 modified spiral arms
• ~ 50% within ~1 km randomly
distributed
• Others in clusters of 6 stations
arranged randomly over an area
100 to 150 m in diameter
• 256 antennas per station
• 38m station diameter1 km
SKA1-Low: Array of Arrays
18
512
SKA1-Low
“Array”
…
SKA1-Low
“Station”
SKA1-Low
Antenna/Receptor
256
Correlation and
Tied-array Beams
Antenna Beam Station Beam
Building SKA: 1.6MW solar/battery power station
SKA HQ: Jodrell Bank, UK
€20M project.
Almost ready
Expected Performances
SKA1 Frequency Bands
22
Band Frequency Range Bandwidth
LOW 50 - 350 MHz 300 MHz
Mid Band 1 0.35 - 1.05 GHz 700 MHz
Mid Band 2 0.95 - 1.75 GHz 800 MHz
Mid Band 3 1.65 - 3.05 GHz 1 GHz
Mid Band 4 2.80 - 5.18 GHz 2.5 GHz
Mid Band 5a 4.6 - 8.5 GHz 2.5 GHz
Mid Band 5b 8.3 - 15.3 GHz 2.5 GHz
65,536 maximum channels across any bandwidth
zoom windows possible
Band Frequency Range Bandwidth
Mid Band A 1.6 - 5.2 GHz 2.5 GHz
Mid Band B 4.6 - 24 GHz 2 x 2.5 GHz
Mid Band 5c 15 - 24 GHz 2 x 2.5 GHz
Possible upgrade paths in the future:
• Improved performance predictions now available at all frequencies
• Opportunity for seamless interface of SKA to ALMA capabilities
SKA1 Anticipated Sensitivity
• Improved performance predictions now available at all frequencies
• Opportunity for seamless interface of SKA to ALMA capabilities
SKA1 Anticipated Survey Speed
SKA1 Image Quality Comparison
• Between 10 and 100 times the image quality of current facilities
• Single SKA1-Low “dirty” snap-shot compared to LOFAR “dirty” snap-shot
SKA1 Image Quality Comparison
• Between 10 and 100 times the image quality of current facilities
• Single “dirty” SKA1-Mid snap-shot compared to combination of four
“dirty” snap-shots, one in each of VLA A+B+C+D
Current status
Precursor: MeerKAT in the Karoo: 64 dishes.
In commissioning phase
SKA dishes
China/Germany
/South
Africa/Italy
Building SKA : dishes
SKA-P2 in transit to South Africa
Precursor: Australian SKA Pathfinder;
operational
MWA Phase 2: operational
Cardiff Seminar, 16 May 2018
• EDGES in the MRO : Experiment to Detect the Global Epoch of Reionization Signature
• (Not!) SKA Precursors3
2
Bowmann et al. 2018,
Nature, 555, 67
Absorption dip on 3K background, 180 million years after BB, due to H heated by
early stars
Building SKA: SKA Aperture Array Verification System1;S KA1-Low prototypeNL/Aus/Italy/UK/India/NZ
• SKALA4 design for SKA1-Low antenna
– Improved: sensitivity, smoothness, polarisation purity, beam shape
SKA1-Low Antenna Development
SKALA1-2: Open boom, 9 dipoles SKALA3: Open boom, 9 dipoles SKALA4: Closed boom, 11 – 18 dipoles
SKALA4: Closed boom, optimised
Building SKA: prototypesNL/Aus/NZ Canada
UK/Aus
RSA/UK/India/NZ/Aus
Building SKA: prototypes
Sweden
…testing in Canada
Italy
South Africa UK
• ‘Standard’ CDR– Having completed all engineering trades analysis (PDR), CDR
demonstrates a fully compliant design that is ready to manufacture (for a specified cost with a bounded uncertainty).
• SKA-TEL-SKO-0000652-01 Critical Design Review Definition– Develop the design solutions in such detail as to permit the
analytical evaluation of the ability of the design approach to meet the specified requirements.
– Confirm compatibility with internal and external interfaces.
– Define the processes related to manufacturing, verification (test) and installation in such detail as to permit the evaluation with a high degree of confidence of the associated risks (on a technical, cost and schedule basis).
– Analyse the operation and maintenance aspects with identification of procedures, tools and cost (manpower, spare parts, etc.).
– Prepare the as-designed documentation set.
CDR Mission
SaDT CDR - May 2018
Cardiff Seminar, 16 May 2018
• Result of Cost Control Project last year -
approved by Board, July 2017
• Design baseline for which CDRs will be
carried out is unchanged• deployment baseline is scoped to match the construction budget
• Design/Deployment Baselines3
8
+ 64* + 64* * 64 MeerKAT dishes
Cost €M
Design Baseline 798
Deployment Baseline 675
Operations (/yr) 89
Ops Deployment (/yr) 77
SKA Data
Data flow4
0
SKA1-LOW
SKA1-M ID
7.2 Tb/ s
8.8 Tb/ s
~50 PFlops
~5 Tb/ s
~250 PFlops
~300 PB/ yr
~2 Pb/ s
Global internet traffic ~360 Tb/s(Cisco: 2016)
Data Flow
• Ordinarily, the science data processor is not considered a part of the telescope; however– data reduction should never interrupt data acquisition
– data rates and volumes emerging from central signal processor are so high that we will not be in a position to store the raw data from the Central Signal Processor
– it will be cheaper to re-observe than store the raw data indefinitely
• The science data processor becomes a schedulable resource of the telescope for observation planning
Signals
Dishes
Antennae
Central Signal
Processor
Science Data
Processor
SKA Regional
Centre
The Telescope
Data Flow
• SKA Regional Centres (SRCs) will host the SKA science archive
• Provide access and distribute data products to users
• Provide access to compute and storage resources
• Provide analysis capabilities & user support
• Multiple regional SRCs, locally resourced and staffed
Cardiff Seminar, 16 May 2018
• Data flow challenges4
2
Observatory Data Products flow from the Science Data Processors in
Perth and Cape Town to SRCs around the globe
Cardiff Seminar, 16 May 2018
• Data flow challenges4
3
Observatory Data Products flow from the Science Data Processors in
Perth and Cape Town to SRCs around the globe
(NREN: National Research and Education Networks)
Cardiff Seminar, 16 May 2018
• a collaborative network for collaborative science
• transparent and location agnostic interface for users
• all SKA users access their project data via SRCs
• a place for development of software tools: analysis, modelling, visualisation
• A collaborative model for SKA Regional Centres4
5
Cardiff Seminar, 16 May 2018
• Summer 2017 saw the establishment of a
Collaboration Agreement between CERN and
SKA• work on topics of mutual interest
• workshops - meetings
• roadmap
• CERN-SKA Collaboration4
6
• Overall progress is excellent:
– Technical progress moving well, dealing with challenges
– Precursors/pathfinders being delivered; delivering science
– Critical design review ongoing
– Treaty establishing SKA Observatory to be signed soon
– HQ construction almost complete.
• SKA only possible through the drive, enthusiasm and support of the science and engineering community and governments of partner nations.
Summary