Herding KAT's Francois Kapp Sub-system manager: DBE [email protected] +27(0)21-531 7282 Introduction

• From zero(?) to World Class(?) • ROACHn • katADC • XDM • Fringe Finder • Holography • KAT-7 • MeerKAT • SKA and CASPER? From “Zero” to “World Class”

• Little interferometry experience in South Africa prior to SKA bid • HartRAO – now working again! • Decision to build an array • System Engineering approach • Military style iterative development • Hard stop in 2012 • Leads to parallel paths Technology: ROACH2 Technology: katADC XDM

Glitch observed in Vela pulsar (PSR J0835-4510) • eXperimental Development Model ATel #2768; S.J. Buchner (Hartebeesthoek Radio Astronomy Observatory) • Builton 1 Aug at 2010; the 19:46 relative UT luxury of HartRAO Distributed as an Instant Email Notice (Request for Observations) • 15m diameter with a cluster feed (7 possible, 2 populated) Password Certification: Sarah Buchner ([email protected]) • Single iBOB with iADC Subjects: Radio, Gamma Ray, Request for Observations, Pulsars • Handed over to HartRAO for scientific use

• ResolvedContinuous monitoring a number observations of smaller of the Vela issues Pulsar (PSR – mainly J0835-4510) with the manufacturing of have been made using the 15m Karoo Array Telescope (KAT) prototype at the composite dishes Hartebeesthoek Radio Astronomy Observatory (HartRAO). We report that an increase in the rotation frequency of PSR J0835-4510 of magnitude [Delta(nu)]/nu = +1.94 E-6 has been observed, using the KAT prototype, with the "glitch" occurring on Jul. 31.802 UT. Fourteen hours of observations, commencing 7.4 hours after the event, indicate an accompanying fractional increase in the spin-down rate of +0.075 +/- 0.001. Observing continues using the 15m KAT prototype and the 26m HartRAO antennae in order to parametrize the post-glitch recovery. Fringe Finder

• Took the leap to the Karoo • 4 element, single ROACH wideband (256MHz) correlator • Used for commissioning KAT-7 telescopes • Found Fringes December 2009 • Raster Image of Centaurus A in March 2010 • Interferometry Image Holography

• 524 Msps • Coarse delay - delay compensation for cable length • Mix down to -1.5MHz • Anti-aliasing filter • Decimate by 8 → BW = 32.75MHz • 8192 point FFT (Xilinx) → channel resolution 3.997803kHz. • 512 channels (~ 2MHz) → full stokes • Accumulate ~0.5 seconds • Pass to SW for further processing KAT-7

• 7 x 12m centre-fed single pixel dishes • 1200 MHz – 1950 MHz, down-converted (72 MHz – 328 MHz) <35K T • SYS • 20m – 200m baselines • Analogue fibre to correlator • Sampled using katADC at 800 Msps • 256 MHz, 16 element correlator • Spectral Line Mode • Beam former • Receivers not yet cooled MeerKAT

• RFP: Large Projects • URS In development • Concept Design Review • System Specification by end 2010 • Telescope phase 1 – 64 – 80 antenna, 0.9 – 1.75 GHz, baselines up to 8 km • Phase 2 – Add spur to extend maximum baseline to ~50km – Add low frequency feed (0.59 – 1.1 GHz) • Phase 3 – Add high frequency feed (8 – 14.5 GHz) Proposed DBE Architecture Full 1024 MHz, n=64 512 MHz + NB, n=64 Cost vs BW (n = 64)

Cost9 vs Processed Bandwidth

8 ) 7 D

6 S

U 5 -

4 M

( Cost ($M) 3 t s 2 o

1 C

0 0 500 1000 1500 2000 2500 3000 3500

Processed Bandwidth (MHz) Cost vs N (BW = 1024 MHz)

9Correlator Cost vs N 80 Cost ($M) 8 70 Approx Power

) 7 60 (kW) D 6 S 50 No of Racks

U 5

- 40 4 M

( 30

3 t

s 20 2 o

10

C 1

0 0 0 20 40 60 80 100 120 140

N Proposed DBE Architecture

• Selected numbers: – For 80 Antennae/1024 MHz processed BW: • Number of ROACH2's: 592 • Number of 10GbE switch ports: 1021 • Number of MeerKATADC's: 160 – For 64 antennae/1024 MHz processed bandwidth: • Number of ROACH2's: 192 • Number of 10GbE switch ports: 649 • Number of MeerKATADC's: 128 – ROACH2 assumed production cost: $8570 – MeerKATADC assumed production cost: $7650 MeerKAT – After CoDR

Fall-back Recommended 2014 2016 Plan B 2015 SKA & CASPER

• SKA Signal Processing Concept Design Review coming up • SKA phase 1 – 250 Dishes, 450 MHz – 3 GHz – 50 SAA Stations, 70 – 450 MHz – Completed by 2019 • Possible SW and hybrid options • Similar study requested for a CASPER SKA phase 1