AUGUST 2017

Francois Kapp (on behalf the entire SKA South Africa team)

MeerKAT Status

www.ska.ac.za

www.ska.ac.za

MeerKAT

MeerKAT construction - Dishes 64 x 13.5m highly efficient offset Gregorian dishes spread over 8 km (~75% within ~1km diameter)

MeerKAT construction – Feeds and Digitisers

MeerKAT construction – Time and Frequency Reference

MeerKAT construction – Correlator Beamformer

MeerKAT construction – Array Releases

• Array releases: planned engineering milestones to enable early integration, test, verification and observations to support this

• AR1 – June 2016 • AR1.5 – March 2017 • AR2 – late 2017 • AR3 – Q2 2018

• Followed by commissioning and

then science use

MeerKAT construction

Receivers: L-band receivers (0.9–1.67 GHz) UHF (0.58–1.0 GHz) S-band (1.75–3.5 GHz) X-band (8 – 14.5 GHz) planning stage

Extremely good L-band performance - Tsys

Note: the resonant peak at 1420MHz is a measurement artifact that could not be calibrated out with sufficient accuracy

Extremely good L-band performance – Ae/Tsys

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KAT-7 (engineering testbed) image in 2012

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4-dish MeerKAT in May 2016 (commissioning)

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16-dish MeerKAT in June 2016 (Array Release 1)

1% of First Light image

www.ska.ac.za

www.ska.ac.za

www.ska.ac.za

www.ska.ac.za

www.ska.ac.za

Technical challenges

MeerKAT Data Rates

MeerKAT SDP Hardware Landscape

1.6 PFLOPs (GPU)

23 PBytes (Disk - CEPH)

40 PBytes (Tape)

www.ska.ac.za

● 32 dishes available (square surrounding core is 1.2 km on the side)

● SKA SA commissioning team making a variety of observations to test telescope

● Closer commissioning interaction with LSP teams starting in May 2017

Array configuration in April 2017

www.ska.ac.za

Commissioning in April 2017, up to 32 antennas

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● 4K channels

● 16 antennas dual-polarisation

● 12 hour track observed on 2017-04-04

● Imaged with 2 x phase + 1 x amplitude self-calibration on 16 s timescale

● With Briggs -0.5 weighting image has 9 μJy/beam (vs 10 μJy/beam in June 2016 image)

● Thermal is ~8.5 μJy/beam

● 1800 sources in central degree of field (vs 1400 in first light image)

“DEEP2 “

Early 8 km-baseline observations

Array layout

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(Tom Mauch)

FRII type galaxy – offset vs centred

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● 32K channels (140 imaged)

● 16 core antennas, dual polarisation

● 9 hour track, 2017-04-05

● Mosaic: 7 pointings

● ~50 minutes per pointing

● Min baseline (projected): 16 m

● Max baseline: 711 m

● Beam 90x70 arcsec

● Measured rms 2.8 mJy (emission-free chan) vs 2.3 theoretical

(Spiral galaxy at 5 Mpc discovered in Cape Town in 1752 by Louis de La Caille)

HI emission in M83

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M83 (Sean Passmoor)

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● 8 channel binning

● No self-cal or primary beam corrections

● Imaged using wsclean:

● Multifrequency synthesis (7 channels)

● Multiscale (largest scale ~70 arcmin)

● Briggs robust 0

● Beamsize 58x64 arcsec

G330.89-0.36 star forming region (continuum, 32k mode)

● ATCA SGPS: 5 configs, 30 m – 3 km baselines

● Smoothed resolution 100 arcsec, sensitivity up to ~30 arcmin

ATCA (Sharmila Goedhart)

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● Hint of extended source in SUMSS

● 7-point MeerKAT mosaic in 4K mode

● Radio source (blue) angular size = 0.8 deg; elliptical galaxy (red/IR) at z = 0.02; linear size = 1.2 Mpc: GRG

(Nadeem Oozeer)

A newly identified Giant Radio Galaxy

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An extra (cool) detection in the new DEEP2 pointing (Spiral galaxy in continuum [and optical] at 70 Mpc)

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● AR2 within weeks

● AR3 within months (Q2 2018)

● Many hours of Commissioning

● Formal operations

● Eventually: Integration with SKA1…

MeerKAT: What is next?

Thanks

SKA South Africa, a Business Unit of the National Research Foundation, is supervising South Africa’s involvement in the SKA on behalf of the Department of Science & Technology.