zurich june 11 2018...digital tv fm cardiff seminar, 16 may 2018 •why build the ska at such remote...

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

N

➤➤

N©2018AfriGIS(Pty)Ltd.

©2018AfriGIS(Pty)Ltd.


©2018Google

©2018Google

©2018Google

ImageLandsat/Copernicus



SKA1-Mid

MeerKAT

Karoo Region

South Africa

SKA1 –Mid: Layout

14

• 133 SKA 15m dishes

• 64 MeerKAT 13.5m dishes


• 3 logarithmic spiral arms

• ~ 50% within ~2 km

randomly distributed

SKA1-LOW

2km

N

➤➤

N©2018AfriGIS(Pty)Ltd.



Image©2018DigitalGlobe



©2018Google

©2018Google

©2018Google

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


• 3 modified spiral arms

SKA1-LOW

SKA1 – LOW: Layout

17

• 512 aperture array stations


• 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


• 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


• 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


• Data flow challenges4

2

Observatory Data Products flow from the Science Data Processors in

Perth and Cape Town to SRCs around the globe


• 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)


• 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


• 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

Thank you

www.skatelescope.org

http://www.skatelescope.org/

zurich june 11 2018...digital tv fm cardiff seminar, 16 may 2018 •why build the ska at such remote...

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